4 installation steps, 10 requirements and medium selection of ball mill | fote machinery

4 installation steps, 10 requirements and medium selection of ball mill | fote machinery

Ball mill installation is a must step before it is put into production, which will affect the subsequent use of the ball mill, and even affect the production volume, crushing rate, service life, etc., so the importance of ball mill installation is self-evident.

In addition, the choice of grinding medium is also crucial. In the grinding process, different grinding medium can be used for different materials, models and equipment, which can reduce production costs and improve production efficiency.

There are four chassis should be installed: the front tile base, the rear tile base, the motor chassis and the reducer chassis. During the installation of the chassis, the horizontality and horizontal elevation of the chassis must be checked by a level or level gauge and a steel rule.

At the same time, the width of these wedges should be between 50 and 60 mm; the length should be at least ensured to exceed the centerline of the anchor bolts inside the chassis, and the outside should be exposed to a length of 10 to 50 mm; the slope of the wedge should be between 1:10 and 1:20.

If the actual combined size between the motor cylinder and the hollow shaft is inconsistent with the technical documents of the equipment or the relevant design, the construction may be carried out according to the actual size after obtaining the consent of the relevant unit personnel.

The transverse centerlines of the two main bearing chassis must coincide and allow for a combined error of no more than 0.5 mm. The non-horizontal degree of the main bearing chassis is allowed to differ by 0.1 mm/m, and the error of the non-parallelism is 0.5 mm/m, but the ball mill must be ensured to discharge materials.

Before the installation of the spherical surface of the main bearing, it is necessary to carefully check whether there are blisters, pores, cracks and other defects on the babbitt surface and the spherical surface, and there is no possibility of shrinking the shell in the interval between the hollow shaft and the contact surface of the bushing. phenomenon.

Firstly, before assembling the cylinder and the end cap, check the cylinder to ensure that the ellipse of the cylinder is not larger than 4 of the diameter of the cylinder. And meanwhile, the ovality and surface smoothness of the hollow journal should also be checked.

After the end cap and the cylinder bolt hole are aligned with the positioning pin, put a 1/4 number of bolts and tighten by hand, one-third of which are half tightened, and the concentricity is adjusted within 0.25mm, and then tightened.

Next, the cylinder and end cap assembly are transferred into the main bearing, but the housing must be adjusted to meet the requirements before the cylinder and end cap assembly are installed in the main bearing.

After assembling, the assembled cylinder should be measured and the total length and the length of the center of the two journals are compared with the center distance of the bearing housing to make sure they match with each other, otherwise, the bearing housing or the position of the main base need to be adjusted.

The inner surface of the ball mill cylinder is generally equipped with liners of various shapes that are the main wearing parts of the ball mill, and whose cost is about 2%-3% of the price of the whole product.

Thus, the performance and service life of the lining plate are issues that users are very concerned about, for its performance will directly affect the performance of the ball mill. The following are the 10 requirements for the liner installation.

The greater the density of the grinding medium is, the shorter the grinding time is. In order to increase the grinding effect, the hardness of the grinding medium must be greater than the hardness of the material to be ground.

According to long-term experience, the Mohs hardness of the medium is preferably greater than the hardness of the material to be ground by more than three grades. In addition, the smaller the size of the grinding medium is, the more the contact points it will be.

The loading amount has a direct influence on the grinding efficiency, and the particle size of the grinding medium determines the loading amount of the grinding medium. It must be ensured that when the grinding medium moves in the disperser, the porosity of the medium is not less than 40%.

For different fineness requirements, it is necessary to adjust the ability of the grinding medium to break and grind. The filling rate is high and the grinding ability is strong. On the contrary, the crushing ability is weak. When super fine grinding, the high filling rate is generally adopted.

Grinding medium generally is spherical because other irregularly shaped medium can wear themselves and cause unnecessary contamination. The size of the medium directly affects the grinding efficiency and product fineness.

The larger the diameter is, the larger the product size and the yield are. Conversely, the smaller the particle size is, the smaller the particle size and the the yield are. In actual production, it is generally determined by the feed size and the required product fineness.

Generally speaking, in the continuous grinding process, the size of the grinding medium is distributed regularly. The medium size ratio is directly related to whether the grinding ability can be exerted and how to reduce the wear of the medium.

In the process, it will not always maintain at a fixed medium ratio. So, the method of replenishing large balls is used to restore the grinding of the system. It is difficult for the mill to maintain at a fixed medium ratio for a long time.

In the production process, it is necessary to explore the appropriate ratio according to the type of material and the characteristics of the process, and remove the too small medium in time to reduce the cost.

The wear resistance and chemical stability of the grinding medium are important conditions for measuring the quality of the grinding medium. The non-wearing media needs to be supplemented by the need of abrasion, which not only increases the cost, but more importantly affects the production.

As common grinding equipment, ball mills are widely used in power, chemical, mining, cement and other processing sectors. At present, there are many kinds of ball mills popular in the market, with various functions and different prices.

Therefore, enterprises often face a dazzling situation when purchasing. Generally, when selecting a ball mill, the company must combine the material properties, abrasive requirements, production environment, energy consumption and other factors through scientifically comparing to select the ball mill that is most suitable for its use requirements.

As a leading mining machinery manufacturer and exporter in China, we are always here to provide you with high quality products and better services. Welcome to contact us through one of the following ways or visit our company and factories.

Based on the high quality and complete after-sales service, our products have been exported to more than 120 countries and regions. Fote Machinery has been the choice of more than 200,000 customers.

ball mill maintenance & installation procedure

ball mill maintenance & installation procedure

Am sure your BallMill is considered the finest possible grinding mill available. As such you will find it is designed and constructed according to heavy duty specifications. It is designed along sound engineering principles with quality workmanship and materials used in the construction of the component parts. YourBallMill reflects years of advancement in grinding principles, materials, and manufacturing techniques. It has been designed with both the operators and the erectors viewpoints in mind. Long uninterrupted performance can be expected from it if the instructions covering installation and maintenance of the mill are carried out. You may be familiar with installing mills of other designs and manufacture much lighter in construction. YourBallis heavy and rugged. It should, therefore, be treated accordingly with due respect for its heavier construction.

The purpose of this manual is to assist you in the proper installation and to acquaint you a bit further with the assembly and care of this equipment. We suggest that these instructions be read carefully and reviewed by everyone whenever involved in the actual installation and operation of the mill. In reading these general instructions, you may at times feel that they cover items which are elementary and perhaps not worthy of mention; however in studying hundreds of installations, it has been found that very often minor points are overlooked due to pressure being exerted by outside influences to get the job done in a hurry. The erection phase of this mill is actually no place to attempt cost savings by taking short cuts, or by-passing some of the work. A good installation will pay dividends for many years to come by reduced maintenance cost.With the modern practice of specialized skills and trades, there is often a line drawn between responsibilities of one crew of erectors and another. Actually the responsibility of installation does not cease with the completion of one phase nor does it begin with the starting of another. Perhaps a simple rule to adopt would be DO NOT TAKE ANYTHING FOR GRANTED. This policy of rechecking previously done work will help guarantee each step of the erection and it will carefully coordinate and tie it into subsequent erection work. To clarify or illustrate this point, take the example of concrete workers completing their job and turning it over to the machinist or millwright. The latter group should carefully check the foundation for soundness and correctness prior to starting their work.

Sound planning and good judgement will, to a great extent, be instrumental in avoiding many of the troublesome occurrences especially at the beginning of operations. While it is virtually impossible to anticipate every eventuality, nevertheless it is the intention of this manual to outline a general procedure to follow in erecting the mill, and at the same time, point out some of the pitfalls which should be avoided.

Before starting the erection of the mill, adequate handling facilities should be provided or made available, bearing in mind the weights and proportions of the various parts and sub-assemblies. This information can be ascertained from the drawings and shipping papers.

The gearing, bearings, and other machined surfaces have been coated with a protective compound, and should be cleaned thoroughly with a solvent, such as Chlorothene, (made by Dow Chemical). Judgement should be exercised as to the correct time and place for cleaning the various parts. Do not permit solvents, oil or grease to come in contact with the roughened top surfaces of the concrete foundation where grouting is to be applied; otherwise proper bonding will not result.

After cleaning the various parts, the gear and pinion teeth, trunnion journals and bearings, shafting and such, should be protected against rusting or pitting as well as against damage from falling objects or weld splatter. All burrs should be carefully removed by filing or honing.

Unless otherwise arranged for, the mill has been completely assembled in our shop. Before dismantling, the closely fitted parts were match marked, and it will greatly facilitate field assembly to adhere to these match marks.

The surfaces of all connecting joints or fits, such as shell and head flanges, trunnion flanges, trunnion liner and feeder connecting joints, should be coated with a NON-SETTING elastic compound, such as Quigley O-Seal, or Permatex to insure against leakage and to assist in drawing them up tight. DO NOT USE WHITE LEAD OR GREASE.

Parts which are affected by the hand of the mill are easily identified by referring to the parts list. In general they include the feeder, feed trunnion liner, discharge trunnion liner if it is equipped with a spiral, spiral type helical splitter, and in some cases the pan liners when they are of the spiral type. When both right and left hand mills are being assembled, it is imperative that these parts which involve hand be assembled in the correct mill.

Adequate foundations for any heavy equipment, and in particular grinding mills, are extremely important to assure proper operation. The foundation should preferably be in one piece, that is, with a reinforced slab footing (so called mat) extending under both trunnion bearing foundations as well as the pinion bearing foundation. If possible or practical, it should be extended to include also the motor and drive. With this design, in the event of some movement, the mill and foundation will tend to move as a unit. ANY SLIGHT SETTLING OF FOUNDATIONS WILL CAUSE BEARING AND GEAR MISALIGNMENT, resulting in excessive wear and higher maintenance costs. It has been found that concrete foundations on a weight basis should be at least 1 times the total weight of the grinding mill with its grinding media.

Allowable bearing pressure between concrete footings and the soil upon which the foundation rests should first be considered. The center of pressure must always pass through the center of the footing. Foundations subject to shock should be designed with less unit pressure than foundations for stationary loads. High moisture content in soils reduces the amount of allowable specific pressure that the ground can support. The following figures may be used for preliminary foundation calculations.

Portland cement mixed with sand and aggregate in the proper proportions has come to be standard practice in making concrete. For general reference cement is usually shipped in sacks containing one cubic foot of material. A barrel usually holds 4 cubic feet. Cement will deteriorate with age and will quickly absorb moisture so it should be stored in a dry place. For best results the sand and gravel used should be carefully cleaned free of humus, clay, vegetal matter, etc.

Concrete may be made up in different mixtures having different proportions of sand and aggregate. These are expressed in parts for example a 1:2:4 mixture indicates one bag of cement, 2 cubic feet of sand, and 4 cubic feet of gravel. We recommend a mixture of 1:2:3 for ball mill and rod mill foundations. The proper water to sand ratio should be carefully regulated since excess water increases the shrinkage in the concrete and lends to weaken it even more than a corresponding increase in the aggregate. Between 5 to 8 gallons of water to a sack of cement is usually recommended, the lower amount to be used where higher strength is required or where the concrete will be subject to severe weathering conditions.

Detailed dimensions for the concrete foundation are covered by the foundation plan drawing submitted separately. The drawing also carries special instructions as to the allowance for grouting, steel reinforcements, pier batter, foundation bolts and pipes. During concrete work, care should be taken to prevent concrete entering the pipes, surrounding the foundations bolts, which would limit the positioning of the bolts when erecting the various assemblies. Forms should be adequately constructed and reinforced to prevent swell, particularly where clearance is critical such as at the drive end where the gear should clear the trunnion bearing and pinion bearing piers.

For convenience in maintenance, the mill foundations should be equipped with jacking piers. These will allow the lifting of one end of the mill by use of jacks in the event maintenance must be carried out under these conditions.

Adequate foundations for any heavy equipment, and in particular Marcy grinding mills, are extremely important to assure proper operation of that equipment. Any slight settling of foundations will cause bearing and gear misalignment, resulting in excessive wear and higher maintenance costs. It has been found that concrete foundations on a weight basis should be approximately 1 times the total weight of the grinding mill with its grinding media.

Allowable bearing pressure between concrete footings and the soil upon which the foundation rests should first be considered. The center of pressure must always pass through the center of the footing. Foundations subject to shock should be designed with less unit pressures than foundations for stationary loads. High moisture content in soils reduces the amount of allowable pressure that that material can support. The following figures may be used for quick foundation calculations:

Portland cement mixed with sand and aggregate in the proper proportions has come to be standard practice in making concrete. For general reference cement is usually shipped in sacks containing one cubic foot of material. A barrel usually consists of 4 cubic feet. Cement will deteriorate with age and will quickly absorb moisture so it should be stored in a cool, dry place. The sand and gravel used should be carefully cleaned for best results to be sure of minimizing the amount of sedimentation in that material.

Concrete may be made up in different mixtures having different proportions of sand and aggregate. These are expressed in parts for example a 1:2:4 mixture indicates one bag of cement, 2 cubic feet of sand, and 4 cubic feet of gravel. We recommend a mixture of 1:2:3 for ball mill and rod mill foundations. The proper water to sand ratio should be carefully regulated since excess water will tend to weaken the concrete even more than corresponding variations in other material ratios. Between 5 to 8 gallons of water to a sack of cement is usually recommended, the lower amount to be used where higher strength is required or where the concrete will be subject to severe weathering conditions.

We recommend the use of a non-shrinking grout, and preferably of the pre-mixed type, such as Embeco, made by the Master Builders Company of Cleveland, Ohio. Thoroughly clean the top surfaces of the concrete piers, and comply with the instructions of the grouting supplier.

1. Establish vertical and horizontal centerline of mill and pinion shaftagainst the effects of this, we recommend that the trunnion bearing sole plate be crowned so as to be higher at the center line of the mill. This is done by using a higher shim at the center than at the endsand tightening the foundation bolts of both ends.

After all shimming is completed, the sole plate and bases should be grouted in position. Grouting should be well tamped and should completely fill the underside of the sole plate and bases. DO NOT REMOVE THE SHIMS AFTER OR DURING GROUTING. When the grout has hardened sufficiently it is advisable to paint the top surfaces of the concrete so as to protect it against disintegration due to the absorption of oil or grease.

If it is felt that sufficient accuracy in level between trunnion bearing piers cannot be maintained, we recommend that the grouting of the sole plate under the trunnion bearing opposite the gear end be delayed until after the mill is in place. In this way, the adjustment by shimming at this end can be made later to correct for any errors in elevation. Depending on local climatic conditions, two to seven days should he allowed for the grouting to dry and set, before painting or applying further loads to the piers.

Pinion bearings are provided of either the sleeve type or anti-friction type. Twin bearing construction may use either individual sole plates or a cast common sole plate. The unit with a common sole plate is completely assembled in our shop and is ready for installation. Normal inspection and cleaning procedure should be followed. Refer to the parts list for general assembly. These units are to be permanently grouted in position and, therefore, care should be taken to assure correct alignment.

The trunnion bearing assemblies can now be mounted on their sole plates. If the bearings are of the swivel type, a heavy industrial water-proof grease should be applied to the spherical surfaces of both the swivels and the bases. Move the trunnion bearings to their approximate position by adjustment of the set screws provided for this purpose.

In the case of ball mills, all internal wearing parts will pass through the manhole, whereas in the case of open end rod mills they will pass through the discharge trunnion opening. When lining the shell, start with the odd shaped pieces around the manhole opening if manholes are furnished. Rubber shell liner backing should be used with all cast type rod mills shell liners. If the shell liners are of the step type, they should be assembled with the thin portion, or toe, as the leading edge with respect to rotation of the mill.

Lorain liners for the shell are provided with special round head bolts, with a waterproof washer and nut. All other cast type liners for the head and shell are provided with oval head bolts with a cut washer and nuts. Except when water proof washers are used, it is advisable to wrap four or five turns of candle wicking around the shank of the bolt under the cut washer. Dip the candle wicking in white lead. All liner bolt threads should be dipped in graphite and oil before assembly. All liner bolt cuts should be firmly tightened by use of a pipe extension on a wrench, or better yet, by use of a torque wrench. The bolt heads should be driven firmly into the bolt holes with a hammer.

In order to minimise the effect of pulp race, we recommend that the spaces between the ends of the shell liners and the head liners or grates be filled with suitable packing. This packing may be in the form of rubber belting, hose, rope or wood.

If adequate overhead crane facilities are available, the heads can be assembled to the shell with the flange connecting bolts drawn tightly. Furthermore, the liners can be in place, as stated above, and the gear can be mounted, as covered by separate instructions. Then the mill can be taken to its location and set in place in the trunnion bearings.

If on the other hand the handling facilities are limited it is recommended that the bare shell and heads be assembled together in a slightly higher position than normal. After the flange bolts are tightened, the mill proper should be lowered into position. Other intermediate methods may be used, depending on local conditions.

In any event, just prior to the lowering of the mill into the bearings the trunnion journal and bushing and bases should be thoroughly cleaned and greased. Care should be taken not to foul the teeth in the gear or pinion. Trunnion bearing caps should be immediately installed, although not necessarily tightened, to prevent dirt settling on the trunnions. The gear should be at least tentatively covered for protection.

IMPORTANT. Unless the millwright or operator is familiar with this type of seal, there is a tendency to assume that the oil seal is too long because of its appearance when held firmly around the trunnion. It is not the function of the brass oil seal band to provide tension for effective sealing. This is accomplished by the garter spring which is provided with the oil seal.

Assemble the oil seal with the spring in place, and with the split at the top. Encircle the oil seal with the band, keeping the blocks on the side of the bearing at or near the horizontal center line so that when in place they will fit between the two dowel pins on the bearing, which are used to prevent rotation of the seal.

Moderately tighten up the cap screws at the blocks, pulling them together to thus hold the seal with its spring in place. If the blocks cannot be pulled snuggly together, then the oil seal may be cut accordingly. Oil the trunnion surface and slide the entire seal assembly back into place against the shoulder of the bearing and finish tightening. Install the retainer ring and splash ring as shown.

In most cases the trunnion liners are already mounted in the trunnions of the mills. If not, they should be assembled with attention being given to match marks or in some cases to dowel pins which are used to locate the trunnion liners in their proper relation to other parts.

If a scoop feeder, combination drum scoop feeder or drum feeder is supplied with the mill, it should be mounted on the extended flange of the feed trunnion liner, matching the dowel pin with its respective hole. The dowel pin arrangement is provided only where there is a spiral in the feed trunnion liner. This matching is important as it fixes the relationship between the discharge from the scoop and the internal spiral of the trunnion liner. Tighten the bolts attaching the feeder to the trunnion liner evenly, all around the circle, seating the feeder tightly and squarely on its bevelled seat. Check the bolts holding the lips and other bolts that may require tightening. The beveled seat design is used primarily where a feeder is provided for the trunnion to trunnion liner connection, and the trunnion liner to feeder connection. When a feeder is not used these connecting joints are usually provided by a simple cylindrical or male and female joint.

If a spout feeder is to be used, it is generally supplied by the user, and should be mounted independently of the mill. The spout should project inside the feed trunnion liner, but must not touch the liner or spiral.

Ordinarily the feed box for a scoop tender is designed and supplied by the user. The feed box should be so constructed that it has at least 6 clearance on both sides and at the bottom of the scoop. This clearance is measured from the outside of the feed scoop.

The feed box may be constructed of 2 wood, but more often is made of 3/16 or plate steel reinforced with angles. In the larger size mills, the lower portion is sometimes made of concrete. Necessary openings should be provided for the original feed and the sand returns from the classifiers when in closed circuit.

A plate steel gear guard is furnished with the mill for safety in operation and to protect the gear and pinion from dirt or grit. As soon as the gear and pinion have been cleaned and coated with the proper lubricant, the gear guard should be assembled and set on its foundation.

Most Rod Mills are provided with a discharge housing mechanism mounted independently of the mill. This unit consists of the housing proper, plug door, plug shaft, arm, and various hinge pins and pivot and lock pins. The door mechanism is extra heavy throughout and is subject to adjustment as regard location. Place the housing proper on the foundation, level with steel shims and tighten the foundation bolts. The various parts may now be assembled to the housing proper and the door plug can be swung into place, securing it with the necessary lock pins.

After the mill has been completely assembled and aligned, the door mechanism centered and adjusted, and all clearances checked, the housing base can be grouted. The unit should be so located both vertically and horizontally so as to provide a uniform annular opening between the discharge plug door and the head liners.

In some cases because of space limitation, economy reasons, etc., the mill is not equipped with separate discharge housing. In such a case, the open end low discharge principal is accomplished by means of the same size opening through the discharge trunnion but with the plug door attached to lugs on the head liner segments or lugs on the discharge trunnion liner proper. In still other cases, it is sometimes effected by means of an arm holding the plug and mounted on a cross member which is attached to the bell of the discharge trunnion liner. In such cases as those, a light weight sheet steel discharge housing is supplied by the user to accommodate the local plant layout in conjunction with the discharge launder.

TRUNNION BEARING LUBRICATION. For the larger mills with trunnion bearings provided with oil seals, we recommend flood oil lubrication. This can be accomplished by a centralized system for two or more mills, or by an individual system for each mill. We recommend the individual system for each mill, except where six or more mills are involved, or when economy reasons may dictate otherwise.

In any event oil flow to each trunnion bearing should be between 3 to 5 gallons per minute. The oil should be adequately filtered and heaters may be used to maintain a temperature which will provide proper filtration and maintain the necessary viscosity for adequate flow. The lines leading from the filter to the bearing should be of copper tubing or pickled piping. The drain line leading from the bearings to the storage or sump tank should be of adequate size for proper flow, and they should be set at a minimum slope of per foot, perferably per foot. Avoid unnecessary elbows and fittings wherever possible. Avoid bends which create traps and which might accumulate impurities. All lines should be thoroughly cleaned and flushed with a solvent, and then blown free with air, before oil is added.

It is advisable to interlock the oil pump motor with the mill motor in such a way that the mill cannot be started until after the oil pump is operating. We recommend the use of a non-adjuslable valve at each bearing to prevent tampering.

When using the drip oil system it is advisable to place wool yarn or waste inside a canvas porous bag to prevent small pieces of the wool being drawn down into the trunnion journal. If brick grease is used, care should be taken in its selection with regard to the range of its effective temperature. In other words, it should be pointed out that brick grease is generally designed for a specific temperature range. Where the bearing temperature does not come up to the minimum temperature rating of the brick grease, the oil will not flow from it, and on the other hand if the temperature of the bearing exceeds the maximum temperature rating of the brick grease, the brick is subject to glazing; therefore, blinding off of the oil. This brick should be trimmed so that it rests freely on the trunnion journal, and does not hang up, or bind on the sides of the grease box.

When replacing the brick grease, remove the old grease completely. Due to the extended running time of brick grease, there is usually an accumulation of impurities and foreign matter on the top surface, which is detrimental to the bearing.

Where anti-friction bearings are supplied, they are adequately sealed for either grease or oil lubrication. If a flood system is used for the trunnion bearings and it is adequately filtered, it can then be used for pinion bearings with the same precautions taken as mentioned above, with a flow of to 1 gallons per minute to each bearing.

These lubricants can be applied by hand, but we highly recommend some type of spray system, whether it be automatic, semi-automatic or manually operated. It has been found that it is best to lubricate gears frequently with small quantities.

Start the lubrication system and run it for about ten minutes, adjusting the oil flow at each bearing. Check all of the bolts and nuts on the mill for tightness and remove all ladders, tools and other obstructions prior to starting the mill.

Before starting the mill, even though it is empty, we recommend that it be jogged one or two revolutions for a check as to clearance of the gear and its guard, splash rings, etc. The trunnion journal should also be checked for uniform oil film and for any evidence of foreign material which might manifest itself through the appearance of scratches on the journal. If there are any scratches, it is very possible that some foreign material such as weld splatter may have been drawn down into the bushing, and can be found imbedded there. These particles should be removed before proceeding further.

If everything is found to be satisfactory, then the mill should be run for ten to fifteen minutes, and stopped. The trunnion bearings should be checked for any undue temperature and the gear grease pattern can be observed for uniformity which would indicate correct alignment.

It should be noted that with an empty mill the reactions and operating characteristics of the bearings and gearing at this point are somewhat different than when operating with a ball or rod charge. Gear noises will be prominent and some vibration will occur due to no load and normal back-lash. Furthermore, it will be found that the mill will continue to rotate for some time after the power is shut off. Safety precautions should therefore he observed, and no work should be done on the mill until it has come to a complete stop.

We have now reached the point where a half ball or rod charge can be added, and the mill run for another six to eight hours, feeding approximately half the anticipated tonnage. The mill should now be stopped, end the gear grease pattern checked, and gear and pinion mesh corrected, if necessary, according to separate instructions.

The full charge of balls or rods can now be added, as well as the full amount of feed, and after a run of about four to six days, ALL BOLTS SHOULD AGAIN BE RETIGHTENED, and the gear and pinion checked again, and adjusted if necessary.

Where starting jacks are provided for the trunnion bearings of the larger sized mills, they should be filled with the same oil that is used for the lubrication of the trunnion bearings. Before starting the mill they should be pumped so as to insure having an oil film between the journal and the bushing.

When relining any part of the mill, clean away all sand from the parts to be relined before putting in the new liners. For the head liners and shell liners you may then proceed in the same manner used at the time of the initial assembly.

Before relining the grate type discharge head, it is advisable to refer to the assembly drawings and the parts list.Because of such limitations as the size of the manhole opening, and for various other reasons, it will be found that the center discharge liner and cone designs vary. The cone may be a separate piece or integral with either the trunnion liner, or the router discharge liner. Furthermore, it will be found in some mills that the center discharge liner is held by bolts through the discharge head, whereas in other cases it depends upon the clamping effect of grates to hold it in position. In any event, the primary thing to remember in assembling the discharge grate head parts is the fact that the grate should be first drawn up tightly towards the center discharge liner by adjusting the grate set screws located at the periphery of the discharge head. This adjustment should be carried out in progressive steps, alternating at about 180 if possible and in such a manner that, the center discharge liner does not become dislodged from its proper position at the center of the mill. These grate set screws should be adjusted with the side clamp bar bolts loosened. After the grates have been completely tightened with the set screws, check for correct and uniform position of each grate section. The side clamp bar bolts may now be lightened, again using an alternate process. This should result in the side clamp bars firmly bearing against the beveled sides of the grates. The side clamp bars should not hear against the lifter liners.

When new pan liners are installed, they should be grouted in position so as to prevent pulp race in the void space between the discharge head and the pan liner. Another good method of preventing this pulp race is the use of the sponge rubber which can be cemented in place.

After the mill is erected, in order to avoid overlooking both obvious and obscure installation details, we recommend the use of a check list. This is particularly recommended for multiple mill installations where it is difficult to control the different phases of installation for each and every mill. Such a check list can be modeled after the following:

No. 1 Connecting Bolts drawn tight. A. Head and Shell flange bolts. B. Gear Connecting, bolts. No. 2 Trunnion studs or bolts drawn up tight. No. 3 Trunnion liner and feeder connecting bolts or studs drawn up tight. No. 4 Feeder lip bolts tightened. No. 5 Liner bolts drawn up tight. No. 6 Gear. A. Concentric B. Backlash C. Runout D. Joint bolts drawn up tight. No. 7 Coupling and Drive alignment and lubrication. No. 8 Bearings and Gearing cleaned and lubricated. No. 9 Lubrication system in working order with automatic devices including alarms and interlocking systems.

We further recommend that during the first thirty to sixty days of operation, particular attention be given to bolt tightness, foundation settlement and condition of the grouting. We suggest any unusual occurrence be recorded so that should trouble develop later there may be a clue which would simplify diagnosing and rectifying the situation.

As a safety precaution, and in many cases in order to comply with local safety regulations, guards should be used to protect the operators and mechanics from contact with moving parts. However, these guards should not be of such a design that will prevent or hinder the close inspection of the vital parts. Frequent inspection should be made at regular intervals with particular attention being given to the condition of the wearing parts in the mill. In this way, you will be better able to anticipate your needs for liners and other parts in time to comply with the current delivery schedules.

When ordering repair or replacement parts for your mill, be sure to identify the parts with the number and description as shown on the repair parts list, and specify the hand and serial number of the mill.

By following the instructions outlined in this manual, mechanical malfunctions will be eliminated. However, inadvertent errors may occur even under, the most careful supervision. With this in mind, it is possible that some difficulties may arise. Whenever any abnormal mechanical reactions are found, invariably they can be attributed to causes which though sometimes obvious are often hidden. We sight herewith the most common problems, with their solutions.

Cause A GROUT DISINTEGRATION. Very often when the grouting is not up to specification the vibration from the mill tends to disintegrate the grouting. In most instances the disintegration starts between the sole plate and the top surface of the grouting near or at the vertical centerline of the mill. As this continues, the weight of the mill causes the sole plate and trunnion bearing base to bend with a resultant pinching action at the side of the bearing near the horizontal center line of the mill. This pinching will cut off and wipe the oil film from the journal and will manifest itself in the same manner as if the lubrication supply had been cut off. If the grout disintegration is limited to about . 050 and does not appear to be progressing further, the situation can be corrected by applying a corresponding amount of shimming between the trunnion bearing base and the sole plate near the centerline of the mill in such a fashion that the trunnion bearing base has been returned to its normal dimensional position. If, on the other hand, the grouting is in excess of . 050 and appears to be progressing further, it is advisable to shut down operations until the sole plate has been re grouted.

Cause B HIGH SPOT ON THE BUSHING. While all BallMill bushings are scraped in the shop to fit either a jig mandrel or the head proper to which it is to be fitted, nevertheless there is a certain amount of seasoning and dimensional change which goes on in the type of metals used. Therefore if high spots are found, the mill should be raised, the bushings removed and rescraped. Bluing may be used to assist in detecting high spots.

Cause C INSUFFICIENT OIL FLOW. Increase the oil supply if it is a flood oil system. If brick grease is used, it is possible that the particular grade of brick may not be applicable to the actual bearing temperature. Refer to the remarks in this manual under the paragraph entitled Lubrication.

Cause E EXCESSIVE RUBBING ON THE SIDE OF THE BUSHING. This comes about due to the improper setting of the bearings in the longitudinal plane. In some cases, particularly on dry grinding or hot clinker grinding mills, the expansion of the mills proper may account for this condition. In any event, it can be remedied by re-adjusting the bearing base on the sole plate longitudinally at the end opposite the drive.

There are many more lubricant suppliers, such as E. F. Houghton and Co. , or Lubriplate Division of Fiske Bros. Refining Co. In making your final selection of lubricants, you should consider the actual plant conditions as well as the standardization of lubricants. New and improved lubricants are being marketed, and we, therefore, suggest that you consult your local suppliers.

ball mills

ball mills

In all ore dressing and milling Operations, including flotation, cyanidation, gravity concentration, and amalgamation, the Working Principle is to crush and grind, often with rob mill & ball mills, the ore in order to liberate the minerals. In the chemical and process industries, grinding is an important step in preparing raw materials for subsequent treatment.In present day practice, ore is reduced to a size many times finer than can be obtained with crushers. Over a period of many years various fine grinding machines have been developed and used, but the ball mill has become standard due to its simplicity and low operating cost.

A ball millefficiently operated performs a wide variety of services. In small milling plants, where simplicity is most essential, it is not economical to use more than single stage crushing, because the Steel-Head Ball or Rod Mill will take up to 2 feed and grind it to the desired fineness. In larger plants where several stages of coarse and fine crushing are used, it is customary to crush from 1/2 to as fine as 8 mesh.

Many grinding circuits necessitate regrinding of concentrates or middling products to extremely fine sizes to liberate the closely associated minerals from each other. In these cases, the feed to the ball mill may be from 10 to 100 mesh or even finer.

Where the finished product does not have to be uniform, a ball mill may be operated in open circuit, but where the finished product must be uniform it is essential that the grinding mill be used in closed circuit with a screen, if a coarse product is desired, and with a classifier if a fine product is required. In most cases it is desirable to operate the grinding mill in closed circuit with a screen or classifier as higher efficiency and capacity are obtained. Often a mill using steel rods as the grinding medium is recommended, where the product must have the minimum amount of fines (rods give a more nearly uniform product).

Often a problem requires some study to determine the economic fineness to which a product can or should be ground. In this case the 911Equipment Company offers its complete testing service so that accurate grinding mill size may be determined.

Until recently many operators have believed that one particular type of grinding mill had greater efficiency and resulting capacity than some other type. However, it is now commonly agreed and accepted that the work done by any ballmill depends directly upon the power input; the maximum power input into any ball or rod mill depends upon weight of grinding charge, mill speed, and liner design.

The apparent difference in capacities between grinding mills (listed as being the same size) is due to the fact that there is no uniform method of designating the size of a mill, for example: a 5 x 5 Ball Mill has a working diameter of 5 inside the liners and has 20 per cent more capacity than all other ball mills designated as 5 x 5 where the shell is 5 inside diameter and the working diameter is only 48 with the liners in place.

Ball-Rod Mills, based on 4 liners and capacity varying as 2.6 power of mill diameter, on the 5 size give 20 per cent increased capacity; on the 4 size, 25 per cent; and on the 3 size, 28 per cent. This fact should be carefully kept in mind when determining the capacity of a Steel- Head Ball-Rod Mill, as this unit can carry a greater ball or rod charge and has potentially higher capacity in a given size when the full ball or rod charge is carried.

A mill shorter in length may be used if the grinding problem indicates a definite power input. This allows the alternative of greater capacity at a later date or a considerable saving in first cost with a shorter mill, if reserve capacity is not desired. The capacities of Ball-Rod Mills are considerably higher than many other types because the diameters are measured inside the liners.

The correct grinding mill depends so much upon the particular ore being treated and the product desired, that a mill must have maximum flexibility in length, type of grinding medium, type of discharge, and speed.With the Ball-Rod Mill it is possible to build this unit in exact accordance with your requirements, as illustrated.

To best serve your needs, the Trunnion can be furnished with small (standard), medium, or large diameter opening for each type of discharge. The sketch shows diagrammatic arrangements of the four different types of discharge for each size of trunnion opening, and peripheral discharge is described later.

Ball-Rod Mills of the grate discharge type are made by adding the improved type of grates to a standard Ball-Rod Mill. These grates are bolted to the discharge head in much the same manner as the standard headliners.

The grates are of alloy steel and are cast integral with the lifter bars which are essential to the efficient operation of this type of ball or rod mill. These lifter bars have a similar action to a pump:i. e., in lifting the product so as to discharge quickly through the mill trunnion.

These Discharge Grates also incorporate as an integral part, a liner between the lifters and steel head of the ball mill to prevent wear of the mill head. By combining these parts into a single casting, repairs and maintenance are greatly simplified. The center of the grate discharge end of this mill is open to permit adding of balls or for adding water to the mill through the discharge end.

Instead of being constructed of bars cast into a frame, Grates are cast entire and have cored holes which widen toward the outside of the mill similar to the taper in grizzly bars. The grate type discharge is illustrated.

The peripheral discharge type of Ball-Rod Mill is a modification of the grate type, and is recommended where a free gravity discharge is desired. It is particularly applicable when production of too many fine particles is detrimental and a quick pass through the mill is desired, and for dry grinding.

The drawings show the arrangement of the peripheral discharge. The discharge consists of openings in the shell into which bushings with holes of the desired size are inserted. On the outside of the mill, flanges are used to attach a stationary discharge hopper to prevent pulp splash or too much dust.

The mill may be operated either as a peripheral discharge or a combination or peripheral and trunnion discharge unit, depending on the desired operating conditions. If at any time the peripheral discharge is undesirable, plugs inserted into the bushings will convert the mill to a trunnion discharge type mill.

Unless otherwise specified, a hard iron liner is furnished. This liner is made of the best grade white iron and is most serviceable for the smaller size mills where large balls are not used. Hard iron liners have a much lower first cost.

Electric steel, although more expensive than hard iron, has advantage of minimum breakage and allows final wear to thinner section. Steel liners are recommended when the mills are for export or where the source of liner replacement is at a considerable distance.

Molychrome steel has longer wearing qualities and greater strength than hard iron. Breakage is not so apt to occur during shipment, and any size ball can be charged into a mill equipped with molychrome liners.

Manganese liners for Ball-Rod Mills are the world famous AMSCO Brand, and are the best obtainable. The first cost is the highest, but in most cases the cost per ton of ore ground is the lowest. These liners contain 12 to 14% manganese.

The feed and discharge trunnions are provided with cast iron or white iron throat liners. As these parts are not subjected to impact and must only withstand abrasion, alloys are not commonly used but can be supplied.

Gears for Ball-Rod Mills drives are furnished as standard on the discharge end of the mill where they are out of the way of the classifier return, scoop feeder, or original feed. Due to convertible type construction the mills can be furnished with gears on the feed end. Gear drives are available in two alternative combinations, which are:

All pinions are properly bored, key-seated, and pressed onto the steel countershaft, which is oversize and properly keyseated for the pinion and drive pulleys or sheaves. The countershaft operates on high grade, heavy duty, nickel babbitt bearings.

Any type of drive can be furnished for Ball-Rod Mills in accordance with your requirements. Belt drives are available with pulleys either plain or equipped with friction clutch. Various V- Rope combinations can also be supplied.

The most economical drive to use up to 50 H. P., is a high starting torque motor connected to the pinion shaft by means of a flat or V-Rope drive. For larger size motors the wound rotor (slip ring) is recommended due to its low current requirement in starting up the ball mill.

Should you be operating your own power plant or have D. C. current, please specify so that there will be no confusion as to motor characteristics. If switches are to be supplied, exact voltage to be used should be given.

Even though many ores require fine grinding for maximum recovery, most ores liberate a large percentage of the minerals during the first pass through the grinding unit. Thus, if the free minerals can be immediately removed from the ball mill classifier circuit, there is little chance for overgrinding.

This is actually what has happened wherever Mineral Jigs or Unit Flotation Cells have been installed in the ball mill classifier circuit. With the installation of one or both of these machines between the ball mill and classifier, as high as 70 per cent of the free gold and sulphide minerals can be immediately removed, thus reducing grinding costs and improving over-all recovery. The advantage of this method lies in the fact that heavy and usually valuable minerals, which otherwise would be ground finer because of their faster settling in the classifier and consequent return to the grinding mill, are removed from the circuit as soon as freed. This applies particularly to gold and lead ores.

Ball-Rod Mills have heavy rolled steel plate shells which are arc welded inside and outside to the steel heads or to rolled steel flanges, depending upon the type of mill. The double welding not only gives increased structural strength, but eliminates any possibility of leakage.

Where a single or double flanged shell is used, the faces are accurately machined and drilled to template to insure perfect fit and alignment with the holes in the head. These flanges are machined with male and female joints which take the shearing stresses off the bolts.

The Ball-Rod Mill Heads are oversize in section, heavily ribbed and are cast from electric furnace steel which has a strength of approximately four times that of cast iron. The head and trunnion bearings are designed to support a mill with length double its diameter. This extra strength, besides eliminating the possibility of head breakage or other structural failure (either while in transit or while in service), imparts to Ball-Rod Mills a flexibility heretofore lacking in grinding mills. Also, for instance, if you have a 5 x 5 mill, you can add another 5 shell length and thus get double the original capacity; or any length required up to a maximum of 12 total length.

On Type A mills the steel heads are double welded to the rolled steel shell. On type B and other flanged type mills the heads are machined with male and female joints to match the shell flanges, thus taking the shearing stresses from the heavy machine bolts which connect the shell flanges to the heads.

The manhole cover is protected from wear by heavy liners. An extended lip is provided for loosening the door with a crow-bar, and lifting handles are also provided. The manhole door is furnished with suitable gaskets to prevent leakage.

The mill trunnions are carried on heavy babbitt bearings which provide ample surface to insure low bearing pressure. If at any time the normal length is doubled to obtain increased capacity, these large trunnion bearings will easily support the additional load. Trunnion bearings are of the rigid type, as the perfect alignment of the trunnion surface on Ball-Rod Mills eliminates any need for the more expensive self-aligning type of bearing.

The cap on the upper half of the trunnion bearing is provided with a shroud which extends over the drip flange of the trunnion and effectively prevents the entrance of dirt or grit. The bearing has a large space for wool waste and lubricant and this is easily accessible through a large opening which is covered to prevent dirt from getting into the bearing.Ball and socket bearings can be furnished.

Scoop Feeders for Ball-Rod Mills are made in various radius sizes. Standard scoops are made of cast iron and for the 3 size a 13 or 19 feeder is supplied, for the 4 size a 30 or 36, for the 5 a 36 or 42, and for the 6 a 42 or 48 feeder. Welded steel scoop feeders can, however, be supplied in any radius.

The correct size of feeder depends upon the size of the classifier, and the smallest feeder should be used which will permit gravity flow for closed circuit grinding between classifier and the ball or rod mill. All feeders are built with a removable wearing lip which can be easily replaced and are designed to give minimum scoop wear.

A combination drum and scoop feeder can be supplied if necessary. This feeder is made of heavy steel plate and strongly welded. These drum-scoop feeders are available in the same sizes as the cast iron feeders but can be built in any radius. Scoop liners can be furnished.

The trunnions on Ball-Rod Mills are flanged and carefully machined so that scoops are held in place by large machine bolts and not cap screws or stud bolts. The feed trunnion flange is machined with a shoulder for insuring a proper fit for the feed scoop, and the weight of the scoop is carried on this shoulder so that all strain is removed from the bolts which hold the scoop.

High carbon steel rods are recommended, hot rolled, hot sawed or sheared, to a length of 2 less than actual length of mill taken inside the liners. The initial rod charge is generally a mixture ranging from 1.5 to 3 in diameter. During operation, rod make-up is generally the maximum size. The weights per lineal foot of rods of various diameters are approximately: 1.5 to 6 lbs.; 2-10.7 lbs.; 2.5-16.7 lbs.; and 3-24 lbs.

Forged from the best high carbon manganese steel, they are of the finest quality which can be produced and give long, satisfactory service. Data on ball charges for Ball-Rod Mills are listed in Table 5. Further information regarding grinding balls is included in Table 6.

Rod Mills has a very define and narrow discharge product size range. Feeding a Rod Mill finer rocks will greatly impact its tonnage while not significantly affect its discharge product sizes. The 3.5 diameter rod of a mill, can only grind so fine.

Crushers are well understood by most. Rod and Ball Mills not so much however as their size reduction actions are hidden in the tube (mill). As for Rod Mills, the image above best expresses what is going on inside. As rocks is feed into the mill, they are crushed (pinched) by the weight of its 3.5 x 16 rods at one end while the smaller particles migrate towards the discharge end and get slightly abraded (as in a Ball Mill) on the way there.

We haveSmall Ball Mills for sale coming in at very good prices. These ball mills are relatively small, bearing mounted on a steel frame. All ball mills are sold with motor, gears, steel liners and optional grinding media charge/load.

Ball Mills or Rod Mills in a complete range of sizes up to 10 diameter x20 long, offer features of operation and convertibility to meet your exactneeds. They may be used for pulverizing and either wet or dry grindingsystems. Mills are available in both light-duty and heavy-duty constructionto meet your specific requirements.

All Mills feature electric cast steel heads and heavy rolled steelplate shells. Self-aligning main trunnion bearings on large mills are sealedand internally flood-lubricated. Replaceable mill trunnions. Pinion shaftbearings are self-aligning, roller bearing type, enclosed in dust-tightcarrier. Adjustable, single-unit soleplate under trunnion and drive pinionsfor perfect, permanent gear alignment.

Ball Mills can be supplied with either ceramic or rubber linings for wet or dry grinding, for continuous or batch type operation, in sizes from 15 x 21 to 8 x 12. High density ceramic linings of uniform hardness male possible thinner linings and greater and more effective grinding volume. Mills are shipped with liners installed.

Complete laboratory testing service, mill and air classifier engineering and proven equipment make possible a single source for your complete dry-grinding mill installation. Units available with air swept design and centrifugal classifiers or with elevators and mechanical type air classifiers. All sizes and capacities of units. Laboratory-size air classifier also available.

A special purpose batch mill designed especially for grinding and mixing involving acids and corrosive materials. No corners mean easy cleaning and choice of rubber or ceramic linings make it corrosion resistant. Shape of mill and ball segregation gives preferential grinding action for grinding and mixing of pigments and catalysts. Made in 2, 3 and 4 diameter grinding drums.

Nowadays grinding mills are almost extensively used for comminution of materials ranging from 5 mm to 40 mm (3/161 5/8) down to varying product sizes. They have vast applications within different branches of industry such as for example the ore dressing, cement, lime, porcelain and chemical industries and can be designed for continuous as well as batch grinding.

Ball mills can be used for coarse grinding as described for the rod mill. They will, however, in that application produce more fines and tramp oversize and will in any case necessitate installation of effective classification.If finer grinding is wanted two or three stage grinding is advisable as for instant primary rod mill with 75100 mm (34) rods, secondary ball mill with 2540 mm(11) balls and possibly tertiary ball mill with 20 mm () balls or cylpebs.To obtain a close size distribution in the fine range the specific surface of the grinding media should be as high as possible. Thus as small balls as possible should be used in each stage.

The principal field of rod mill usage is the preparation of products in the 5 mm0.4 mm (4 mesh to 35 mesh) range. It may sometimes be recommended also for finer grinding. Within these limits a rod mill is usually superior to and more efficient than a ball mill. The basic principle for rod grinding is reduction by line contact between rods extending the full length of the mill, resulting in selective grinding carried out on the largest particle sizes. This results in a minimum production of extreme fines or slimes and more effective grinding work as compared with a ball mill. One stage rod mill grinding is therefore suitable for preparation of feed to gravimetric ore dressing methods, certain flotation processes with slime problems and magnetic cobbing. Rod mills are frequently used as primary mills to produce suitable feed to the second grinding stage. Rod mills have usually a length/diameter ratio of at least 1.4.

Tube mills are in principle to be considered as ball mills, the basic difference being that the length/diameter ratio is greater (35). They are commonly used for surface cleaning or scrubbing action and fine grinding in open circuit.

In some cases it is suitable to use screened fractions of the material as grinding media. Such mills are usually called pebble mills, but the working principle is the same as for ball mills. As the power input is approximately directly proportional to the volume weight of the grinding media, the power input for pebble mills is correspondingly smaller than for a ball mill.

A dry process requires usually dry grinding. If the feed is wet and sticky, it is often necessary to lower the moisture content below 1 %. Grinding in front of wet processes can be done wet or dry. In dry grinding the energy consumption is higher, but the wear of linings and charge is less than for wet grinding, especially when treating highly abrasive and corrosive material. When comparing the economy of wet and dry grinding, the different costs for the entire process must be considered.

An increase in the mill speed will give a directly proportional increase in mill power but there seems to be a square proportional increase in the wear. Rod mills generally operate within the range of 6075 % of critical speed in order to avoid excessive wear and tangled rods. Ball and pebble mills are usually operated at 7085 % of critical speed. For dry grinding the speed is usually somewhat lower.

The mill lining can be made of rubber or different types of steel (manganese or Ni-hard) with liner types according to the customers requirements. For special applications we can also supply porcelain, basalt and other linings.

The mill power is approximately directly proportional to the charge volume within the normal range. When calculating a mill 40 % charge volume is generally used. In pebble and ball mills quite often charge volumes close to 50 % are used. In a pebble mill the pebble consumption ranges from 315 % and the charge has to be controlled automatically to maintain uniform power consumption.

In all cases the net energy consumption per ton (kWh/ton) must be known either from previous experience or laboratory tests before mill size can be determined. The required mill net power P kW ( = ton/hX kWh/ton) is obtained from

Trunnions of S.G. iron or steel castings with machined flange and bearing seat incl. device for dismantling the bearings. For smaller mills the heads and trunnions are sometimes made in grey cast iron.

The mills can be used either for dry or wet, rod or ball grinding. By using a separate attachment the discharge end can be changed so that the mills can be used for peripheral instead of overflow discharge.

ball mill for sale | grinding machine - jxsc mining

ball mill for sale | grinding machine - jxsc mining

Ball mill is the key equipment for grinding materials. those grinding mills are widely used in the mining process, and it has a wide range of usage in grinding mineral or material into fine powder, such as gold, ironzinc ore, copper, etc.

JXSC Mining produce reliable effective ball mill for long life and minimum maintenance, incorporate many of the qualities which have made us being professional in the mineral processing industry since 1985. Various types of ball mill designs are available to suit different applications. These could include but not be restricted to coal mining grate discharge, dry type grinding, wet mineral grinding, high-temperature milling operations, stone & pebble milling.

A ball mill grinds ores to an end product size of thirty-five mesh or finer. The feeding material to a ball mill is treated by: Single or multistage crushing and screening Crushing, screening, and/or rod milling Primary crushing and autogenous/semi-autogenous grinding.

Normal feed sizes: eighty percent of six millimeters or finer for hard rocker eighty percent of twenty-five millimeters or finer for fragile rocks (Larger feed sizes can be tolerated depending on the requirements).

The ratio of machine length to the cylinder diameter of cylindrical type ball mills range from one to three through three to one. When the length to diameter ratio is two to one or even bigger, we should better choose the mill of a Tube Mill.

Grinding circuit design Grinding circuit design is available, we experienced engineers expect the chance to help you with ore material grinding mill plant of grinding circuit design, installation, operation, and optimization. The automatic operation has the advantage of saving energy consumption, grinding media, and reducing body liner wear while increasing grinding capacity. In addition, by using a software system to control the ore grinding process meet the requirements of different ore milling task.

The ball mill is a typical material grinder machine which widely used in the mineral processing plant, ball mill performs well in different material conditions either wet type grinding or dry type, and to grind the ores to a fine size.

Main ball mill components: cylinder, motor drive, grinding medium, shaft. The cylinder cavity is partial filling with the material to be ground and the metal grinding balls. When the large cylinder rotating and creating centrifugal force, the inner metal grinding mediums will be lifted to the predetermined height and then fall, the rock material will be ground under the gravity force and squeeze force of moving mediums. Feed material to be ground enters the cylinder through a hopper feeder on one end and after being crushed by the grinding medium is discharged at the other end.

Mining Equipment Manufacturers, Our Main Products: Gold Trommel, Gold Wash Plant, Dense Media Separation System, CIP, CIL, Ball Mill, Trommel Scrubber, Shaker Table, Jig Concentrator, Spiral Separator, Slurry Pump, Trommel Screen.

energy and cost comparisons of hpgr-based circuits | e & mj

energy and cost comparisons of hpgr-based circuits | e & mj

A comprehensive energy and cost study compared an existing SAG mill-based circuit at the Huckleberry mine with two proposed circuits involving comminution technologies that are associated with energy efficiency: high-pressure grinding rolls (HPGR) and high-speed stirred mills. The specific energy requirements, expressed as kilowatt-hours per metric ton (kWh/mt), for the proposed circuits were determined from pilot-scale HPGR and stirred mill testing conducted at the University of British Columbia (UBC).

Samples and operating data were collected from Huckleberrys copper-molybdenum concentrator to evaluate current mill performance for comparison. To support the base case, the current Huckleberry mill circuit was modeled using JK SimMet software. The main comparison focused on the complete energy requirements for each circuit, including materials handling equipment such as conveyors, screens, feeders and pumps. Capital and operating cost estimates for each of the comminution circuits are also given.

The results showed that the HPGR-ball mill circuit achieved a 21% reduction in energy consumption over the existing SAG-ball mill circuit at the same P80 grind size of 160 mircons (m). At a grind of 80% passing 75 m, the HPGR-stirred mill circuit showed a 34% reduction in energy compared to the base case. The energy reduction for the new flowsheets significantly improved the economics of the Huckleberry comminution process.

IntroductionUp until now, tumbling mills such as AG/SAG mills and ball mills have had a dominant bearing on the design andeconomics of comminution circuits. However, it is commonly agreed thatthe majority of employed comminution processes are energy intensive and energy inefficient, accounting for up to 80% of overall process plant energy consumption and having an efficiency of as lowas 1%. The U.S. Department of Energy reported that there is a potential to reduce energy consumption in the metals industry by up to 61% from current practice to best estimated practical minimum energy consumption; suggestions included the implementation of best practices and the adoption of energy efficient mining and mineral processing technologies such as advanced blasting techniques, HPGR and stirred mills.

The concept of combining an HPGR and a stirred mill in a single flowsheet has been proposed, which was envisioned to be an example of the future in energy conscious comminution processes. The pilot-scale HPGR and high-speed stirred mill testing facility at the UBC Norman B. Keevil Institute of Mining Engineering provided a very unique opportunity to assess the HPGR and/or stirred mill circuits and understand the potential benefits. To examine a combined HPGR and stirred mill circuit, both machines have to be operated outside their currently accepted operating conditions. Studies have demonstrated that an HPGR-stirred mill circuit is technically feasible and showed promising benefits over the traditional stage crushers-ball mill circuit and HPGR-ball mill circuits.

To determine whether the novel HPGR-stirred mill circuit arrangement could achieve energy savings in comparison to conventional SAG mill-based circuits, a pilot-scale study was conducted to compare the energy requirements of the existing circuit at the Huckleberry mine to two alternative circuits: an HPGR-ball mill circuit and a novel HPGR-stirred mill circuit. The study was conducted in collaboration with the Huckleberry mine with support from BC Hydro, Xstrata Technology and Koeppern.

Data representative of three hours of continuous mill operation, directly preceding mill shutdown and sample collection, was analyzed to confirm process stability and subsequently to determine the actual specific energy requirement of Huckleberry process equipment. A sample was collected and analyzed using established comminution laboratory testing methodologies, characterizing the properties of the ore and slurry for modeling and simulation of the circuit.

The sample consisted of a 1,000-kg SAG belt-cut sample, at nominally 100% passing 100 mm, and two buckets of cyclone overflow slurry. The feed material had a moisture content of 3% with a specific gravity (SG) of 2.76. The battery limits for the energy study were established as being the feed to the SAG circuit (coarse ore stockpile) and cyclone overflow of the ball-mill grinding circuit (feed to flotation circuit).

The collected SAG feed sample was prepared for pilot-scale HPGR and stirred mill testing to determine the key operating parameters for flowsheet design and power-based calculations. Ultimately, the simulation and test results allowed for the direct comparison of the energy and costs for three circuits.

The current process configuration at the Huckleberry operation is based on a SAG mill operating with a pebble crusher and ball mills, commonly referred to as an SABC type comminution circuit (See Figure 1). Modeling of the SABC circuit using JKSimMet was carried out using known equipment parameters, operational data and the results of material analyses as inputs. The JKSimMet model was used to confirm the validity of acquired data and to model the effects of modifying certain areas of the comminution flowsheet.

The HPGR-ball mill circuit comprises a reverse-closed secondary crushing circuit prior to a closed HPGR circuit, followed by a reversed-closed ball-mill circuit with cyclones (See Figure 2). The vibrating screen decks were set to an aperture size of 32 and 4 mm for the secondary crushing stage and HPGR screen circuit, respectively. The energy requirements for the secondary crushing stage and the ball-mill grinding stage were determined using the previously fitted JKSimMet model. A number of pilot-scale HPGR tests were carried out to determine the proper operating conditions. Energy values obtained from pilot HPGR testing, laboratory testing and JKSimMet modeling were combined to calculate the specific energy requirement for this circuit.

The novel HPGR-stirred mill circuit is comprised of a reverse-closed secondary crushing circuit prior to an open HPGR circuit, and followed by a second HPGR in closed circuit to generate finer feed for high-speed stirred milling (See Figure 3). The vibrating screen decks were set to aperture sizes of 32 and 0.71 mm for the closed secondary crushing stage and second stage HPGR screening circuit, respectively. The energy requirements of the secondary crusher were determined using the JKSimMet crusher model. A number of pilot-scale HPGR tests were carried out to determine the proper operating conditions for the first stage of HPGR crushing. Recycle tests were performed to simulate the HPGR performance in closed circuit with a screen and to determine the associated specific energy values. Energy readings obtained from pilot HPGR testing, stirred mill testing and JKSimMet modeling were combined to calculate the total specific energy requirement for the proposed novel circuit.

Comparison of All CircuitsThe battery limit for comparison of comminution energy using the proposed circuits was feed from the coarse ore stockpile with an F80 of 66 mm to two product sizes of P80 of 160 m (current target grind for the Huckleberry mine) and P80 of 75 m. For the target grind P80 of 160 m, the existing SABC circuit was compared to an HPGR-ball mill circuit. For this product size, the IsaMill could not be tested because the second stage HPGR product particle size (screen undersize feeding the IsaMill) was only slightly larger than the target P80, such that stirred mill grinding would be impractical. Therefore, to compare all three circuits, the target grind size was selected to be a P80 of 75 m. (See Table 1 and Figure 4)

For grinding to a P80 of 160 m, the HPGR-ball mill circuit required 21% less energy than the SABC circuit. The main savings result from the lower energy required by the HPGR as compared to the SAG mill. However, an additional secondary crusher and conveyer system were required to facilitate the HPGR circuit. The HPGR also produced a coarser product than the SAG mill. Thus, the energy needed for crushing, ball milling and material handling was higher for the HPGR option than the SABC circuit.

When extending the target grind size to a P80 of 75 m, the energy savings of the HPGR-ball mill circuit was only 7%. The novel two-stage HPGR-stirred mill circuit demonstrated a significant reduction in energy of 34%, as compared to the SABC circuit. It must be noted that the energy for any additional equipment, which would be required to disperse the HPGR product prior to screening at 0.71 mm, was not accounted for. However, assuming equipment similar to that of a vertical shaft impacter (VSI) were to be used prior to screening, an overall reduction in energy in excess of 30% would still be expected. In retrospect, the study shows that the application of an HPGR-stirred mill circuit can significantly lower the energy required for mechanical size reduction.

There was a discrepancy in the additional power required to reduce the final product size from 160 to 75 m for SABC circuit and HPGR-ball mill circuit. The HPGR-ball mill circuit when grinding to 75 um compared to 160 um used an extra 4.6 kWh/mt, but for the SABC circuit it only used an extra 1.8 kWh/mt. The reported SABC circuit power for the 160 m grind size was based on actual site data. JKSimMet was used to fit a model to site DCS data. Thus, there was considerable scope to reduce the ball-mill power consumption by using smaller ball-mill grinding media. However, for a final grind of 75 m, the reported power values for both HPGR-ball mill and SABC circuits were based on JKSimMet modeling alone. In these cases, the previously fitted model was optimized through process design changes (media size, transfer size, cyclone parameters etc.) to achieve the 75 m product size while minimizing energy consumption. So the difference in ball-mill power to reduce the final grind size from 160 to 75 m should have been much greater in the case of the SABC circuit than actually reported.

Capital and Operating CostsTo complete the comparison of the process options, capital and operating costs were determined from vendor quotes and installation costs. The costs are deemed to have an accuracy of 50% to a preliminary level of assessment (See Table 2 and 3). For comparison, the costs for SABC circuits grinding to 160 m and 75 m were determined to allow for direct comparison to HPGR-ball mill and HPGR-stirred mill circuits, respectively.

The indirect cost was estimated at 45% of direct capital costs and was considered to be within industry standards for the options considered. A similar approach was applied to estimate the total direct costs. It was found that both HPGR-ball mill and HPGR-stirred mill circuits have higher associated capital costs than the SABC option. Conversely, operating costs for the two proposed circuits are substantially lower, which relates directly to lower energy consumption levels.

The trade-off economics were calculated on the basis of net present value (NPV). A discount rate of 5% and a 15-year mine life were assumed. At a grind of 80% passing 160 m, the HPGR-ball mill circuit shows significant cost advantage over the SABC circuit with a NPV of $33 million and an IRR of 22% (See Table 4). At a product size of 80% passing 75 m, both options have costs advantages over the SABC option, although the HPGR-ball mill circuit had lower overall costs than the two-stage HPGR-stirred mill circuit. In general, a finer grind size would not be selected unless it resulted in significant recovery improvements. Since the copper-molybdenum recovery versus grind size information was not available, such a comparison was not possible for this study. However, in cases where a finer primary grind is needed to achieve high metal recoveries, the two-stage HPGR-stirred mill process demonstrates significant energy savings that would be reflected in the NPV.

DiscussionEvaluation of the proposed circuits showed that combining the two comminution technologies, HPGR and stirred mill, had considerable potential as an energy efficient and economic approach to grinding metallic ores. Overall, the proposed HPGR-based circuits were found to be more energy efficient than the current Huckleberry SABC circuit. Both the higher energy efficiency and elimination of steel grinding media associated with the HPGR-based circuit significantly reduced the determined operating costs.

The effect of ore variability was not evaluated in this study; however, HPGRs are certainly less sensitive to variation in ore hardness when compared to SAG mills. There is also a question of the differences in liberation characteristics from a SAG mill-ball mill operating in closed circuit with a classifying cyclone and the HPGR-stirred mill operating in open circuit. With differences in particle breakage mechanisms as well as mineral particle size distributions (since no cyclone classification is used in stirred mill operation), it would not be surprising to find differences in degree of liberation.

During pilot simulation of the HPGR-stirred mill circuit, both machines were operating outside their respective industry standard conditions. Challenges were primarily associated with the nominated transfer size between the HPGR and stirred mill. For example, nomination of a coarser transfer size necessitated the use of larger stirred-mill grinding media and resulted in a reduction in stirred-mill energy efficiency. Conversely, nomination of a finer cut-point was detrimental to the screening efficiency of HPGR product. Successful development of the HPGR-stirred mill circuit relies on further addressing the efficient separation of HPGR product at a suitable feed size for stirred mill operation. This will likely involve the introduction of an additional piece of material dispersing equipment that would be located prior to the HPGR screens.

Conclusions and RecommendationsThe presented study built on previous related work at the UBC NBK Institute of Mining and showed that an HPGRstirred mill grinding circuit, as an alternative to commonly implemented SABC comminution circuitshas significant potential as an energy efficient alternative. A reduction in energy consumption of 34% was determined to be attainable through implementation of the HPGR-stirred mill circuit when targeting a final P80 grind size of 75 micron. Project economics were also in favor of the proposed circuit and would further improve in regions where energy supply is more expensive than the relatively low energy unit costs used as a basis for this evaluation.

Other advantages identified with the proposed circuit include the resilience of HPGRs and stirred mills to changes in ore hardness. Carrying out further pilot tests using samples taken from different areas of the Huckleberry deposit would allow for this attribute to be quantified in terms of its influence on energy requirements and overall project economics.

Further work is required to improve the classification of HPGR product and to optimize stirred mill parameters for treating coarser feed sizes. The former is particularly challenging when taking into account the detrimental effect of moisture on HPGR performance, thereby necessitating a dry classification process to limit the amount of moisture returned to the HPGR grinding section with oversize particles.

The results of this study clearly show that there is considerable scope for improving the energy efficiency of industry standard comminution grinding circuits. The proposed HPGR-stirred milling has demonstrated significant potential as a means to grinding more efficiently, this attribute being increasingly important as the mining industry is faced with extracting metals from harder and more complex deposits.

C. Wang, O. Mejia and B. Klein are with the University of British Columbia in Vancouver. (Wang can be reached at: [email protected]). S. Nadolski is with Koeppern Machinery Australia in Malaga. J. Drozdiak is with Hatch in Vancouver. This article is adapted from a paper, Energy and Cost Comparisons of HPGR-based Circuits with the SABC Circuit Installed at the Huckleberry Mine, they presented at the 45th Annual Canadian Mineral Processors Operators Conference, which took place in Ottawa, Ontario, January 22-24. To view the entire unedited paper, visit the Resource Center at CEEC: www.ceecthefuture.org/resource-center/.

Canadas Finest Recognized with CEEC MedalThe paper from which this article was derived received the2013 Coalition for Eco-Efficient Comminution (CEEC) Medal. Congratulations to Fisher Wang, Stefan Nadolski, Olav Mejia, Jeff Drozdiak and Bern Klein on their excellent work, said CEEC Chair Elizabeth Lewis-Gray. The business of energy efficiency in grinding and crushing is a global issue and we are delighted that the winners of the prestigious 2013 CEEC Medal authored their outstanding paper as a result of an industry first; collaboration between BC Hydro, University of British Columbia and the mine operator Huckleberry mines. The 2013 Medal recipients are based in North America, specifically in Vancouver, and they join previous CEEC Medal recipients based in Peru, Chile and Australia.

The 2013 Medal was awarded in Vancouver, B.C., before a gathering of industry leaders. More than 60 guests applauded as The Right Honorable Dave Nikolejsin, deputy minister for energy and mines, presented the medals to the winners. Ausenco hosted the event at its Vancouver offices.

The CEEC Medal is a global award intended to recognize and celebrate the contribution of outstanding published papers, articles or case studies profiling beneficial strategies for eco-efficient comminution. In 2013, more than 10 papers were nominated. The Medal review committee is led by CEEC Director Dr. Zeljka Pokrajcic, principal process engineer with WorleyParsons. The committee evaluates all nominated papers on the basis of the papers potential to improve energy efficiency, the ability for the concepts to be readily adapted to operating plants or incorporated in the design of new circuits, that the results are robust and believable, and finally, whether or not the paper communicates its ideas clearly and effectively. The medal committee recommends the annual recipient to the CEEC Board of Directors for its approval.

CEEC is a not-for-profit company funded by sponsorship from the mineral industry itself, whose mission is to accelerate knowledge and technology transfer in the field of energy-efficient comminution (crushing and grinding). CEEC aims to raise awareness of beneficial alternative comminution strategies with the objective of improving earnings, achieving lower processing costs and gaining energy efficiencies in the mining sector.

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trunnion magnet technology delivers quick payback north american mining magazine

trunnion magnet technology delivers quick payback north american mining magazine

Using magnets to collect ferrous metal from process streams has a long history in the mining industry. This is especially true in the collection and disposal of grinding ball fragments in ball/SAG mill operations. Though often small in size, worn and broken metallic grinding balls can cause serious problems if they are not detected and removed from the milling operation.

Eriez Trunnion Magnets provide a unique system for separating and removing balls, chips or scats in a typical ball/SAG mill operation. This technology replaces the dead weight of ball magnets with fresh ore.

By effectively removing an estimated 80% or more of worn or broken media, a trunnion magnet reduces power consumption from the mill drive and prevents expensive damage to other equipment. Observations indicate a 250% increase in equipment life.

How Trunnion Magnets WorkIn a typical grinding mill application, the grinding media eventually fractures and wears into a fine metallic powder because of the heavy re-circulating load in the mill. Energy is unnecessarily wasted to mill the milling media.

As shown in Figure 3, the trunnion magnet is mounted at the ball mill discharge point to replace a trommel screen. It consists of a barrel or blind trommel that is mechanically attached to the trunnion or discharge of a ball mill. The barrel rotates around a fixed assembly of ferrite and rare earth magnets positioned on the outside of the barrel.

The stationary magnetic assembly attracts chips and scats to the inside diameter of the barrel. As the ball mill slurry discharges through the barrel, eight strategically placed lifters inside the barrel carry the ball fragments to the top, where they fall onto a sloping discharge chute.The Trunnion Magnet System includes four basic components: the blind trommel (barrel), magnet sector, support structure and the discharge hopper.

The barrel, or blind trommel, is a short extension that bolts directly to the discharge flange of the ball mill. Its function is to transport the mill discharge material through the magnetic field. It is fabricated from stainless steel and has an abrasion-resistant wear liner. The barrel is fitted with eight equally spaced bi-metallic cleats, which assist capturing and transporting chips into the discharge area.

The magnet sector consists of permanent magnets and has approximately a 200-degree arc. This magnetic arc is mounted on a steel support pedestal and positioned around the blind trommel. The permanent magnets are enclosed in stainless steel canisters and incorporate a steel backbar for support and projection of the magnetic field. Trunnion magnets can also be installed in bi-directional mills using a magnetic sector that covers 310 degrees.

The discharge hopper and support structure are positioned just inside the blind trommel to collect the grinding ball fragments. The hopper collects the grinding ball fragments as they rotate past the end of the magnetic sector at the top of the blind barrel.

Trunnion Magnet Performance AdvantagesTo improve performance, Eriez Trunnion Magnets are available in several design variations so they can be matched to specific ball/SAG mill operations. Mill capacity, ball size and other parameters are used to select and specify the design features for each installation.

When designing the trunnion magnet, Eriez considered the magnetic capture of grinding balls/fragments directly opposed by the drag force of the mill discharge slurry. Several techniques were used in the magnet design to compensate for the drag force:

Economic JustificationThe expenses to continue to use a trommel screen should be considered when comparing against costs to buy a trunnion magnet. Potential trunnion magnet users are using the following guidelines to assess the savings possible after installation:

Retrofitting With Trunnion MagnetsDepending upon user requirements, several variations and modifications of the Trunnion Magnet System are possible. For example, the magnetic circuit is designed to provide maximum strength for high slurry throughputs and up to 4-in. diameter grinding balls. The trunnion magnet can be configured for reversing or bi-directional mills. In addition, the ball retention ring is fitted in the barrel to prevent full-size balls from exiting the mill.

ConclusionThere are hundreds of installations of Eriez Trunnion Magnets worldwide. This system for separating and removing balls, chips or scats in a typical ball/SAG mill operation replaces the dead weight of ball magnets with fresh ore.

By effectively removing 80% or more of the worn or broken media, the trunnion magnet reduces power consumption from the mill drive and prevents expensive damage to other equipment, such as pumps and hydroycyclones. Cost estimates of a typical 18-ft. diameter mill indicate savings of up to $100,000 per year.

how much will it cost?

how much will it cost?

Costs are an inherent aspect of evaluating, advancing and generating profits from any mining property. They often make or break projects and are typically the final stop before go/no go development decisions are made. As such, costs, in some formor another, are one of the biggest topics of discussion in the mining industry. Despite that fact, I would also suggest that the process for obtaining costs is one of the least discussed topics in our industry.

An obvious generic answer to when costs should be obtained and considered might be on-going, but for prefeasibil-ity costing the true answer is when you have a measured and indicated resource. Exploration stage properties or properties with only an inferred resource do require cost considerations (scoping or preliminary economic analysis [PEA]) but they are still too speculative and provide only a hint of what could be. Similarly, if much of your engineering work is complete and of final feasibility detail (feasibility study [FS]), youve waited too long and possibly sunk unnecessary costs into the project. Figure 1 highlights the parameters for each study level.

While these comments may seem rudimentary, the reality is that many in our industry do not fully understand the concept of prefeasibility. It is the authors opinion that prefeasibility is the point at which you have enough scientific data in hand that you can safely say, Ive really got something here!

If you will notice, I have indicated that prefeasibility is contingent upon the amount of scientific data in hand, not engineering data. Generally speaking, when entering a prefeasibility level study, your project will have had very little engineering completed. This is important to remember because the input data is all you will have to work with when we talk about the hurdles that must be overcome to obtain costs.

The output side of a prefeasibility level project provides insight as to what costs are needed and how the costing data is utilized. For example, for a pre-feasibility level project, preliminary equip-ment lists and subsequent development costs are derived based on the results of trade-off studies for proposed mining and pro-cessing methods (Figure 2). Unfortunately, one of the larger tasks encountered during a pre-feasibility study is related to the process of obtaining costs for the needed equipment.

As noted earlier, it is typical at the prefeasibility level to have very little engineering data available. For example, while you mayknow that you have a surface copper project that requires loaders and trucks followed by crushing, milling and flotation, you may not have enough metallurgical work completed to know how fine the material must be ground or how the flotation circuit needs to be configured for the best recovery of all byproducts. This lack of data becomes an issue when you call equipment manufactures to obtain budget quotes for their products.

This issue of a general lack of data is compounded by the highly engineered and integrated systems we have in the mining industry today. This is particularly true for the processing side of the equa-tion, where the cost estimator may no longer be able to simply derive overall costs from off-the-shelf component prices. In fact, most manufacturers of complex processing equipment will not provide component costs at the prefeasibility level.

The time involved to obtain cost data can be substantial on the order of weeks and months given the strategies that must be employed to mitigate the first two hurdles noted earlier. The more complex the project, the more time is needed to prepare quote requests and gather quotes. Time is money.

The acquisition of cost data for prefeasibility level mine development studies is not simple. A thorough understanding of the three primary study levels is required to identify the types and accuracy of costing data appropriate for each level. Moreover, a well identified procurement strategy is recommended to overcome thehurdles associated with the acquisition of costs.

the attentions of ball mill grinder installation and commission - xinhai

the attentions of ball mill grinder installation and commission - xinhai

Ball mill grinder installation accomplishment according to the paper, to ensure all the components are at the right position. The complete installation process should be recorded and acceptance passed.

The bush should be installed on the sector block of lower bearing seat according to the rotation direction of ball mill. The bush should be revised according to the axial guide ring. The bearing seat seal should be installed correctly. The junction should be sealed by a sealant.

Ensuring that all the monitoring equipment are well-connected. The flow monitor, pressure switch and temperature sensor are set well. Oil pressure gauge, thermometer, accident button and interlocking device instructions are reliable.

Connecting with reducer and pinion coupling, and installing protecting mask. Start the lubricating oil system and cooling water system. Turn on the power of the ball mill, press the accident button to stop it, and check the main bearing, motor, and gears to determine whether the direction of rotation of the ball mill is correct. If there is no abnormality, start the ball mill to run for 8 hours.

When running empty, if the lubricating oil system is working normally and there is no oil leakage. The ball mill runs smoothly and there is no obvious noise. The vibration value of the main bearing, motor, and pinion does not exceed 0.1mm, and there is no obvious damage or hot phenomenon to all parts. The empty vehicle runs normally.

According to the ratio of ball mill, a certain amount of steel balls are added into the cylinder of ball mill grinder. Steel balls are added in batches. During operation, measure bearing temperature, current, and vibration intensity everywhere. After the installation of the ball mill is completed, start to run with load, add 70% of the specified load into the grinding material, and continue to run for more than 10 hours. During this process, the liner bolt joint should be fastened and check the bolt connection frequently to prevent the loosen.

During running with load, the ball mill grinder should satisfy the following requirements. The vibration of each part does not exceed 0.1mm; The current of the motor has no abnormal fluctuations; The running process is stable; The noise is small; The connecting bolts are tight, and the cylinder has good sealing.

The above is the whole installation and commission process of ball mill grinder. Xinhai Mining established the commission operation management service center to ensure the correct and favourable installation. Xinhai Mining insists on the service idea professional attitude wins the trusts of clients, helping clients to resolve problems and free from worries.

ball mill, ball grinding mill - all industrial manufacturers - videos

ball mill, ball grinding mill - all industrial manufacturers - videos

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... LN2 feeding systems, jar and ball sizes, adapter racks, materials low LN2-consumption clearly structured user interface, memory for 9 SOPs programmable cooling and grinding cycles (10 ...

The XRD-Mill McCrone was specially developed for the preparation of samples for subsequent X-ray diffraction (XRD). The mill is used for applications in geology, chemistry, mineralogy and materials science, ...

The Planetary Ball Mill PM 200, engineered by Retsch, is a milling device best suited for mixing and size reduction processes and is also capable of meeting the necessary requirements for colloidal grinding ...

... Micro Mill PULVERISETTE 0 is the ideal laboratory mill for fine comminution of medium-hard, brittle, moist or temperature-sensitive samples dry or in suspension as well as for homogenising of emulsions ...

... , fast, effective. WORKING PRINCIPLE Impact and friction The FRITSCH Mini-Mill PULVERISETTE 23 grinds the sample through impact and friction between grinding balls and the inside wall of the grinding ...

... grinding mills includes being safe throughout. When the mills are quoted we make sure to include any and all safety components needed. Long life and minimum maintenance To help you get the most of your ...

Annular gap and agitator bead mills are used for processing suspensions and highly viscous products in chemicals and cosmetics as well as in the food sector. Studies have shown that annular gap bead ...

... Pneumatic extraction from the surface of the agitated media bed Wet grinding: Separation of suspension from the agitated media by ball retaining device Flexibility Through careful selection of the size and quantity ...

... details; Agitating power: 0,37 kW Total Power Consumption : 1.44 kW Total Weight : 100 kg Metal Ball Size : 6.35 mm Metal Ball Amount : 7 kg Cold water consumption : 10 liters / hour ...

Cement Ball Mill Processing ability: - 200 t/h Max feeding size: - 25 mm Product Fineness: - 0.074-0.89mm Range of application: - limestone, calcium carbonate, clay, dolomite and other minerals ...

... grinds and classifies a product. Vilitek MBL-NK-80 mill is specially designed for grinding valuable materials, which, when grinding, the re-milled fractions are not a commodity product. In particular, this mill ...

Dimensions: Height: 1530 mm Width: 650 mm Length : 1025 mm Description: Ball mills are capable of rapidly producing chocolate, nut pastes (for gianduia), and spreadable creams. It has been ...

equinox gold begins mining at santa luz, construction on track to pour first gold in q1 2022

equinox gold begins mining at santa luz, construction on track to pour first gold in q1 2022

VANCOUVER, BC, June 29, 2021 /CNW/ - Equinox Gold Corp. (TSX: EQX) (NYSE American: EQX) ("Equinox Gold" or the "Company") is pleased to announce that mining activities are underway at its new Santa Luz Gold Mine in Brazil ("Santa Luz"). Construction remains on track to commence commissioning in Q4 2021 and pour gold in Q1 2022, with the expectation of producing 110,000 ounces of gold annually for the first five years of operations.

Mining is underway to prepare for gold production in Q1 2022. The mining contractor, U&M Minerao e Construo S/A ("U&M"), mobilized to site in May and mining commenced in mid-June. Mining activities are currently focused on removing waste from two locations and developing access roads, ramps, dumps and ore storage areas in preparation for a pre-stripping campaign prior to mining ore in late 2021. To make room for mine expansion, U&M is also relocating an existing ore stockpile with an average grade of 0.9 grams of gold per tonne, which will be used for commissioning activities in Q4 2021.

Construction is on schedule and on budget, with approximately $31 million of the $103 million construction budget spent and $70 million committed at the end of June 2021. As a brownfield past-producing mine, the majority of site services and infrastructure is already in place at Santa Luz. Restart activities are focused on refurbishing existing infrastructure, retrofitting the plant to incorporate resin-in-leach processing, installation of additional grinding infrastructure and increasing the storage capacities of the existing tailings and water storage facilities. A significant construction milestone was achieved on June 25 with installation of the first segment of the ball mill.

Pre-conditioning, leach and detoxification circuit is 46% complete: concrete bases are complete, steel structures are being pre-assembled and tank installation is underway, with four tanks out of ten fully erected and four more partially erected

Equinox Gold is a growth-focused Canadian mining company operating entirely in the Americas, with seven gold mines and a clear path to achieve one million ounces of annual gold production from a pipeline of development and expansion projects. Equinox Gold's common shares are listed on the TSX and the NYSE American under the trading symbol EQX. Further information about Equinox Gold's portfolio of assets and long-term growth strategy is available at www.equinoxgold.com or by email at [email protected]

This news release contains certain forward-looking information and forward-looking statements within the meaning of applicable securities legislation and may include future-oriented financial information. Forward-looking statements and forward-looking information in this news release relate to, among other things: the Company's ability to successfully complete construction and achieve production at Santa Luz in accordance with current expectations; and the Company's expectations regarding production capabilities and future financial or operating performance of Santa Luz. Forward-looking statements or information generally identified by the use of the words "will", "on track", "expectation", "targeted", "clear path", "underway", and similar expressions and phrases or statements that certain actions, events or results "could", "would" or "should", or the negative connotation of such terms, are intended to identify forward-looking statements and information. Although the Company believes that the expectations reflected in such forward-looking statements and information are reasonable, undue reliance should not be placed on forward-looking statements since the Company can give no assurance that such expectations will prove to be correct. The Company has based these forward-looking statements and information on the Company's current expectations and projections about future events and these assumptions include: construction at Santa Luz being completed and performed in accordance with current expectations, including the project timeline and budget; Equinox Gold's ability to achieve the production, cost and development expectations for its respective operations and projects, including Santa Luz's anticipated annual gold production; prices for gold remaining as estimated; currency exchange rates remaining as estimated; tonnage of ore to be mined and processed; ore grades and recoveries; availability of funds for the Company's projects and future cash requirements; capital, decommissioning and reclamation estimates; Mineral Reserve and Mineral Resource estimates and the assumptions on which they are based; prices for energy inputs, labour, materials, supplies and services; no labour-related disruptions and no unplanned delays or interruptions in scheduled construction, development and production, including by blockade; all necessary permits, licenses and regulatory approvals are received in a timely manner; and the Company's ability to comply with environmental, health and safety laws. While the Company considers these assumptions to be reasonable based on information currently available, they may prove to be incorrect. Accordingly, readers are cautioned not to put undue reliance on the forward-looking statements contained in this news release.

The Company cautions that forward-looking statements and information involve known and unknown risks, uncertainties and other factors that may cause actual results and developments to differ materially from those expressed or implied by such forward-looking statements and information contained in this news release and the Company has made assumptions and estimates based on or related to many of these factors. Such factors include, without limitation: fluctuations in gold prices; fluctuations in prices for energy inputs, labour, materials, supplies and services; fluctuations in currency markets; operational risks and hazards inherent with the business of mining (including environmental accidents and hazards, industrial accidents, equipment breakdown, unusual or unexpected geological or structural formations, cave-ins, flooding and severe weather); inadequate insurance, or inability to obtain insurance to cover these risks and hazards; employee relations; relationships with, and claims by, local communities and indigenous populations; the Company's ability to obtain all necessary permits, licenses and regulatory approvals in a timely manner or at all; changes in laws, regulations and government practices, including environmental, export and import laws and regulations; legal restrictions relating to mining including those imposed in connection with COVID-19; risks relating to expropriation; increased competition in the mining industry; and those factors identified in the Company's MD&A dated March 19, 2021 and its Annual Information Form dated March 24, 2021, both of which relate to the year-ended December 31, 2020, and in the Company's MD&A dated May 5, 2021 for the three months ended March 31, 2021, all of which are available on SEDAR at www.sedar.com and on EDGAR at www.sec.gov/edgar. Forward-looking statements and information are designed to help readers understand management's views as of that time with respect to future events and speak only as of the date they are made. Except as required by applicable law, the Company assumes no obligation to publicly announce the results of any change to any forward-looking statement or information contained or incorporated by reference to reflect actual results, future events or developments, changes in assumptions or changes in other factors affecting the forward-looking statements and information. If the Company updates any one or more forward-looking statements, no inference should be drawn that the Company will make additional updates with respect to those or other forward-looking statements. All forward-looking statements and information contained in this news release are expressly qualified in their entirety by this cautionary statement.

Dividend stocks are the Swiss army knives of the stock market. When dividend stocks go up, you make money. When they dont go up you still make money (from the dividend). Heck, even when a dividend stock goes down in price, its not all bad news, because the dividend yield (the absolute dividend amount, divided by the stock price) gets richer the more the stock falls in price. Knowing all this, wouldnt you like to own find great dividend stocks? Of course you would! Using the TipRanks databas

Signs of panic buying emerged Friday afternoon on the New York Stock Exchange amid a powerful stock-market rally in the final minutes of trade, a day after one of the worst selloffs for equities since mid June. Market internals suggest that investors are buying mightily headed into the weekend. The NYSE Arms Index, a volume-weighted breadth measure, fell to 0.413, with many on Wall Street see declines below 0.500 as suggesting panic buying. The Arms Index is calculated by dividing the ratio of t

While the stocks that pay dividends generally do so on a quarterly basis, there is a select group of companies that pay them out monthly. Here are two REITs that income investors might appreciate knowing about, that pay monthly dividends, and that have above-market yields. Realty Income (NYSE: O) is a Dividend Aristocrat that calls itself The Monthly Dividend Company.

Elizabeth Warren has sharp words for Wells Fargo. The bankis discontinuing personal lines of credit and will shut down existing ones in the coming weeks,CNBC reported,citing customer letters it has reviewed. In a frequently asked questions section of a letter sent by the back, Wells Fargo warned that the discontinuation of such bank accounts may impact customers credit scores.

In this article, we discuss the 20 Chinese companies listed on NYSE/NASDAQ/AMEX. If you want to skip our detailed analysis of these companies, go directly to the 5 Chinese Companies Listed on NYSE/NASDAQ/AMEX. The trade tension between the United States and China over the past few years has dominated headlines around the world, fueling speculation []

As of just before noon EDT, the Nasdaq Composite (NASDAQINDEX: ^IXIC) was up nearly 1% as it looked poised to set another record high. Earnings season is almost here, and that means investors will be looking for signs of how the economy is doing. Banks typically start out early with their reports, and most big banks don't trade on the Nasdaq.

Pitney Bowes is a 100-year-old shipping company, best known for its classic postage meters. Stamps.com got a big boost on Friday when private equity firm Thoma Bravo agreed to acquire it for $330 per share in cash, a premium of 67% to the company's Thursday close.

In this article, we discuss the 10 best Vanguard stocks to buy now based on Vanguard Groups holdings.. If you want to skip our detailed analysis of these stocks, go directly to the 5 Best Vanguard Stocks to Buy Now. Vanguard stocks, which we will analyze in this article based on Vanguard Groups holdings, are []

Interest rates have dropped to near zero, bond yields have fallen substantially from pre-COVID levels, and a number of traditional dividend paying stocks cut or postponed payments due to the pandemic. This compounding effect, combined with rising inflation, has created an environment that has seen real yields (nominal interest rate minus inflation) at their lowest level since the 1970s, as measured by the U.S. 10 Year Treasury bond. The current inflationary environment is, to put it mildly, less than ideal for yield-focused investors especially retirees.

LONDON (Reuters) -Kerry Kraker, 56, has worked in kitchens all his life. Since March he's spent around $100 a week - half his spare cash on silver coins. Thanks to a community of like-minded silver 'stackers' gathering on social-media platform Reddit Inc., Seattle-based Kraker says he also feels empowered.

As of 2021, Jeff Bezos is the richest person on Earth, with his personal fortune eclipsing the wealth amassed by Microsoft Corp. co-founder Bill Gates andlegendary investor Warren Buffett. The founder, former chief executive officer (CEO), and now executive chair of global ecommerce behemoth Amazon.com, Inc., was responsible for running aplatform that accountedforup to 9% of all U.S. retail sales and a whopping51.2% of digital retail spending in 2020. As digitalization reshapes human behavior and the cloud computing revolution does the same to enterprise, the leader in online retail, with its high-flying cloud computing platform Amazon Web Services (AWS), is only forecasted to propel higherspelling more good news for its founder.

What happened Shares of Lucira Health (NASDAQ: LHDX) -- a maker of consumer-friendly at-home COVID-19 tests -- climbed as much as 40% higher Friday afternoon. The move prompted a temporary halt in trading of shares.

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