gyratory crushers

gyratory crushers

The belowimage shows a sectional view of a typical gyratory crusher. This type of machine is, by virtue of chronological priority, known as the standard gyratory crusher. Although it incorporates many refinements in design, it is fundamentally the same crusher that first bore the name of gyratory; its crushing chamber is very much the same shape; the motion is identically the same, and the method of transmitting power from belt to crushing head is similar. It is an interesting fact that the same similarity in essential features of design exists in the case of the standard, or Blake type, jaw crusher, which is something in the way of a tribute to the inspiration and mechanical ability of the men who originated these machines.

Essentially, the gyratory crusher consists of a heavy cast-iron, or steel, frame which includes in its lower part an actuating mechanism (eccentric and driving gears), and in its upper part a cone-shaped crushing chamber, lined with wear-resisting plates (concaves). Spanning the crushing chamber across its top is a steady-rest (spider), containing a machined journal which fixes the position of the upper end of the main shaft. The active crushing member consists of the main shaft and its crushing head, or head center and mantle. This assembly is suspended in the spider journal by means of a heavy nut which, in all but the very large machines, is arranged for a certain amount of vertical adjustment of the shaft and head. At its lower end the main shaft passes through the babbitted eccentric journal, which offsets the lower end of the shaft with respect to the centerline of the crusher. Thus, when the eccentric is rotated by its gear train, the lower end of the main shaft is caused to gyrate (oscillate in a small circular path), and the crushing head, likewise, gyrates within the crushing chamber, progressively approaching, and receding from, each element of the cone-shaped inner surface.

The action of the gyratory crusher, and of the other member of the reciprocating pressure family, the jaw crusher, is fundamentally a simple one, but as will be seen a great deal of thought and some very progressive engineering has been expended upon the design of crushing chambers to increase capacities and to permit the use of closer discharge settings for secondary and fine-reduction crushing (various crusher types).

Referring to the table, always available from the manufacturer, it will be noted that standard gyratory crushers are manufactured in commercial sizes ranging from 8 to 60 receiving openings. Capacities are listed, for minimum and maximum open-side discharge settings, in short tons per hour, and the horsepower requirements for soft and hard materials are listed for each size. The capacities, and the minimum settings, are based upon the use of standard (straight-face) concaves.

Primary gyratory crushers are designated by two numbers. These are the size of the feed opening (in inches) and the diameter of the mantle at its base (in inches). A 60~x~89 crusher would have an opening dimension of 60 inches (152 cm) and a diameter across the base of the mantle of 89 inches (226 cm).

To stand up under the extremely rugged work of reducing hard and tough rock and ore, and in doing so to maintain reasonably true alignment of its running component, the crushermust necessarily be of massive and rigid proportions, rigidity being of equal importance to ultimate strength. Regardless of the tensile strength of the metal used in the main frame, top shell, and spider, these parts must be made with walls and ribs thick enough to provide this rigidity. Therefore it is practicable to use close-grained cast iron, and special high-test mixtures of cast iron, for these parts, if the machine is intended for crushing soft or medium materials. When very hard and tough materials are to be crushed, the machine is usually strengthened by substituting cast steel in one or more of its parts.

Wearing parts in the gyratory crusher may be either chilled cast iron or manganese steel, depending on the character of the material to be crushed and the particular class of service for which the machine is intended. Standard crushers, in the small and medium sizes, are customarily fitted with chilled-iron head and concaves for crushing soft and medium limestone and materials of similar hardness and abrasiveness, because its relatively low first cost and excellent wearing qualities make it the most economical material to use when the service is not too severe. Manganese steel, which combines extreme toughness with unsurpassed wear-resistance, is the universal choice for crushing hard, tough rock regardless of the class of service or type of crusher. Even though the rock be quite soft and non-abrasive, it is general practice to use manganese steel concaves in the larger sizes of primary crushers because of the shocks attendant upon handling large and heavy pieces of rock.

The primary rockbreaker most commonly used in large plants is the gyratory crusher, of which a typical section is shown in Fig. 5.It consists essentially of a gyrating crushing head (521) working inside a crushing bowl (522) which is fixed to the frame (501).

Thecrushing head is carried on a short solid main shaft (515) suspended from the spider (502) by a nut (513) ; the nut fits into the seating of a sleeve (514) which fixes its position in relation to the spider and, therefore, to the frame (501). The lower part of the main shaft fits into a sleeve (530) set in an eccentric (527), to which is keyed the bevel driving gear (528) ; the bevel pinion (533) is similarly fastened to the countershaft (535) and engages with the bevel gear. The whole of this driving assembly is protected from grit and dust by means of a dust seal (524), (525), and (526).

The countershaft carries the driving pulley, and as it revolves it causes the eccentric to rotate ; as it rotates the main shaft gyrates and with it the crushing head ; the top of the shaft at the point of suspension has practically no movement. Although the motion of the head is gyratory, the main shaft is free to rotate in the eccentric and it actually revolves slowly in relation to the bowl, thus equalizing the wear on the mantle (519) which lines the head and on the concave liners (522 and 523) which comprise the bowl. Both mantle and bowl liners are usually made of manganese steel. The suspension nut (513) is adjustable and enables the crushing head and main shaft to be raised in relation to the bowl to compensate for wear. The size of the product is determined by the distance between the bottom edges of the crushing head and the bowl, in the position when they are farthest apart.

The crushing action is much the same in principle as that of a jaw crusher, the lumps of ore being pinched and broken between the crushing head and the bowl instead of between two jaws. The main point ofdifference between the two types is that the gyratory crusher does effective work during the whole of the travel of the head, whereas the other only crushes during the forward stroke. The gyratory crusher is thereforethe more efficient machine, provided that the bowl can be kept full, a condition which is, as a rule, easy to maintain because it is quite safe to bury the head in a pile of ore.

Tables 7 and 8 give particulars of different sizes of gyratory crushers. As in the previous paragraph, the capacity figures are based on material weighing 100 lb. per cubic foot and should be increased in direct proportion for heavier ores.

Primary and secondary gyratory crushers, including the cone crusher, can be directly connected to slow speed motors if desired, but the standard method of drive is still by belt and pulley. Jaw crushers must be belt-driven.

An efficient substitute for the flat belt in all cases is the Texrope drive, which consists of a number of V-shaped endless rubber belts running on special grooved pulleys. The grip of these belts is so great that the distance between the pulley centres can be reduced to about 30% of that required for a flat belt. This results not only in a saving of space but also in greater safety, since the drive is easier to protect and there is no danger of an accident such as might occur if a long belt were to pull through its fasteners. Moreover, the short drive makes it possible for any stretch to be taken up by moving the motor back on its rails without the necessity of cutting and rejoining the belts. The flexibility and ease of maintenance of the Tex-rope drive makes it very suitable for crushing machines.

LOW OPERATING COSTS Vertical adjustment compensates for wear on crushing surfaces (also maintains product uniformity). Oiling system provides proper lubrication throughout, including spider. Effective dust seal prevents dust infiltration to moving parts. Long life bearings, easy to replace.

Strength, of course, makes an all-important contribution to the rugged heavy duty service and day-in, day-out dependability demanded of a crusher. However, strength does not necessarily mean excessive weight. The metals and alloys used in construction and the distribution of weight are actually the determining factors in the strength of a gyratory crusher.

MAINSHAFT ASSEMBLY mainshaft forged steel; annealed quenched and tempered. Tapered to gauge for head center fit. Head center of cast steel. Head mantle of manganese steel. Mainshaft sleeve shrunk on mainshaft to provide renewable wearing surface on spider bearing.

Gyratory crusher advanced design includes the placing of circumferential ribs around the top and bottom shells. These integrally cast reinforcing rings prevent distortion provide the rigidity necessary to maintain true alignment of running parts.

Hollow box construction of the cast steel spider affords maximum strength with the least amount of feed interference. Arms are cast integrally with the heavy outer rim. Crushing stresses are transmitted to the rim, which is taper-fitted to the top shell. Because spider and top shell are interlocked, they reinforce each other to provide maximum stability and rigidity.

The bottom shell is the foundation of the crusher. It must be strong enough not only to support the weight of the crusher, but to withstand extreme crushing stresses (most stresses terminate here) strong enough to protect vital mechanism the eccentric, gears and countershaft assembly housed in the bottom shell. In the Gyratory crusher, bottom discharge design makes possible a compact, squat structure of simplified design and comparatively high strength. Supplementing the strength of the bottom shell are the previously described circumferential ribs. Crushing stresses are transmitted directly to these reinforcing members through three radial arms.

Because the mainshaft does the actual crushing, it must literally possess crushing strength. In the Gyratory crusher, the eccentric is located directly below the crushing head. This design permits the use of a short, rigid mainshaft a mainshaft that will withstand the strain of severe service.

Flexibility is the keynote of the Gyratory crusher efficiency and economy. While your particular installation is designed to best meet your specific and immediate requirements, built-in flexibility permits adaptation to changing operating conditions anytime in the future.

A Gyratory crusher not only affords a maximum capacity-to-size ratio, but provides the variable factors which facilitate increasing or decreasing capacity as the need arises. Flexibility in a Gyratory crusher also permits compensation for wear and assures product uniformity.

In the Gyratory crusher, the use of spiral bevel gears instead of spur gears makes possible the broad range of speeds conducive to meeting varying capacity demands. Because the Gyratory crusher is equipped with an external oiling system, speed may be reduced as much as desired or required. Adequate lubrication is supplied at even the lowest speeds, because the flow of oil is not relative to the crushers operating speed as is the case with an internal system.

With a primary gyratory crusher running at a given countershaft speed, capacity is increased as eccentricity is increased. At a given eccentricity, greater capacity results from higher countershaft speeds. Conversely, reducing either the speed or eccentricity reduces capacity.

Another high capacity characteristic of the Gyratory crusher is a large diameter crushing head. Because the area of discharge opening is directly proportionate to head diameter, high capacities result.

VARIABLE INITIAL SETTINGS The contour of the crushing chamber at the bottom is designed to afford various initial settings without changing the angle of the nip. This is accomplished by installing lower tier concaves of the shape and thickness for the desired setting and capacity.

HOW SIZES ARE DESIGNATED The numerical size designation of Gyratory crushers represents the feed opening and the maximum diameter of the crushing head. For example, a 60-109 Gyratory crusher has a 60-inch receiving opening and an 109-inch maximum diameter crushing head.

ELIMINATES DIAPHRAGM In a gyratory crusher with aside discharge, sticky materials may pack on the diaphragm and eventually cause considerable damage. Thestraight down discharge of the Gyratory crusher is a design simplification that eliminates the diaphragm and itsmaintenance problems.

CONTRIBUTES TO BALANCED CIRCUIT The adaptabilityof a primary crusher to a large extent dictates the plantflowsheet the initial and overall operating costs of subsequent equipment. With a Gyratory primary crusher,these costs are kept at a minimum because the entirecrushing circuit remains in balance. The concrete foundation may be modified for use as a surge bin. This storagecapacity permits controlling the flow of material throughthe plant. Secondary and tertiary crushers, vibrating screens, etc. may be installed in size ranges and types tomeet the requirements of a constant tonnage. For thosefew installations where a side discharge is essential, a discharge spout can be furnished. Another factor in maintaining a balanced circuit is the vertical adjustment(pages 12 and 13) which permits retaining the initial discharge setting by compensating for wear on mantle andconcaves. Related equipment need not be readjusted because of variations of feed size from the primary crusher.

In the Gyratory crusher, the original discharge setting may be maintained for the life of a single set of alloy crushing surfaces with only one resetting of concaves. Raising the mainshaft compensates for wear onconcaves and mantle. This simplified vertical adjustment cuts resetting time facilitates holding product size.

The threaded mainshaft is held in and supported from the spider hub. (See illustration at lower left.) A vertical adjustment range of from 6 inches to approximately 11 inches is possible, depending upon the size of the machine. The original discharge setting can be maintained until the combined wear of mantle and concaves is about one-third of the vertical adjustment.

A cast steel, split adjusting nut with a collar issupported on a two-piece thrust bearing in the spider hub. The nut is threaded for the mainshaft. The outside of the nut is tapered, with the large diameter at the top. The weight of the head and shaft draws the nut down in its tapered seat in the collar to form a self-clamping nut. Desired setting is achieved by positioning split nut in the proper location on the threaded portion of the mainshaft.

The Gyratory crusher is also available with a Hydroset mechanism a hydraulic method of vertical adjustment. With the Hydroset mechanism, compensation for wear and product size control is a one- man, one-minute operation. The Hydroset mechanism consists of a motor-driven gear pump operated by push button.

The accompanying drawings show the simplicity of Hydroset design. The mainshaft assembly is supported on a hydraulic jack. When oil is pumped into the jack, the mainshaft is raised compensating for mantle and concave wear or providing a closer setting. When oil is removed from jack, the mainshaft is lowered and a coarser setting results.

Since the mainshaft assembly is supported on a hydraulic jack, its position with respect to the concaves, and therefore the crusher setting, is controlledby the amount of oil in the hydraulic cylinder.

Oil pressure is maintained in the hydraulic cylinder below the mainshaft by a highly effective chevron packing. The oil supply of the Hydroset mechanism functions independently of the crushers lubrication system.

If a Gyratory crusher equipped with Hydroset mechanism stops under load, the mainshaft may be lowered to facilitate clearing of the crushing chamber by merely pumping oil out of the cylinder. Only under extreme conditions is it necessary to dig out. When the cause of the stoppage is remedied, the oil is pumped back into the cylinder quickly, returning the mainshaft assembly to its initial position.

STEP BEARING consists of bronze mainshaft step, bronze piston wearing plate, and an alloy steel washer between the two. Washer is drilled for oil cooling lubrication. Bearing surfaces are grooved to permit oil distribution.

Utilizing pool lubrication, a gun-type fitting in the spider arm makes it easy to oil the spider bearing. A garter-type oil seal in the bottom of the bearing retains oil. Being flexible, the seal compensates for movement of crusher mainshaft.

The countershaft assembly is an anti-friction, pool-lubricated unit. Both ends of the bearing housing are sealed by garter-type spring oil seals which: (1) keep dust from anti-friction bearings; (2) separate pinion- shaft bearing lubricant from oil lubricating the eccentric and gears.

Getting the most out of a crusher in performance and capacity depends largely upon positive lubrication. And positive lubrication means more than just adequate oil lubrication. It also entails conditioning oil for maximum lubricating efficiency.

The Gyratory crusher is equipped with an externally located, fully automatic lubricating system. Positive and constant lubrication is maintained at all speeds even at the slowest speed. If desired, oil may be circulated through bearings of Gyratory crusher during shutdown periods.

A gear pump circulates oil from storage tank, through crusher and back. Each time oil is pumped to the crusher, it passes through the filter and cooler. The cleaned, cool oil lubricates the step bearing (in Hydroset mechanism only), the eccentric wearing plate and the inner eccentric bearing. At the top of the bearing, most of the oil flows through ports in the eccentric to the outer eccentric bearing. Theoil then flows down the outer eccentric bearing and lubricates the gear and pinion before it is returned to storage. The overflow oil which may have become contaminated is returned immediately to the oil conditioning tank. It does not contact any other wearing parts within the crusher.

The oil conditioning system may be modified to meet your particular applications. In cold climates immersion heaters are installed in the storage tank to preheat oil. This arrangement permits circulating warm oil through the crusher during shutdown periods. A thermostatic control turns heater on and off. Only in a crusher specifically designed for external oiling is it possible to circulate warm oil when the crusher is stopped.

An added measure of safety is providedby the oil conditioning system. Foreignmaterial is removed by pumping warm oilthrough a mechanical filter. After oil isfiltered, it flows through a condenser-type cooler before it is returned to the crusher.

An oil flow switch provides automatic protection against possible damage caused by oil system failure. This switch stops the crusher immediately if oil flow is insufficient for proper lubrication. Interlocks between pump motor and crusher prevent starting crusher before oil circulation begins.

In addition to its other advantages, the externally located oil conditioning system is easy to service. The unit consists of (A) an oil storage tank, (B) a motor-driven gear pump, (C) a pressure- type filter, and (D) a condenser-type cooler.

In the gyratory crusher, expensive castings are protected by replaceable parts. Rim and arm liners protect the spider from wear. Bottom shell liners and shields provide protection below the crushing chamber. An alloy steel shaft sleeve protects the mainshaft in the spider bearing. The eccentric sleeve and bushing are easily replaced when worn.

Because all parts are readily accessible and removable, down time is kept to a minimum. For example, the countershaft assembly is removed as a unit and can be taken to your machine shop for convenient servicing. Eccentric bearings are bronze bushings. Because bronze is used, the need for babbitt mandrels and melting facilities is eliminated.

Sealing out dirt and dust and their equipment-destroying abrasive action results in obvious maintenance economies. The type of dust seal used in the gyratory crusher is the most reliable and effective device ever developed for preventing excessive wear caused by dirt and dust.

In the gyratory crusher, a synthetic, self-lubricating, light-weight ring is used as a dust seal. The ring is enclosed between a dust collar bolted to the bottom shell and a recess in the bottom of the head center. Regardless of the eccentric throw and vertical positioning, the ring maintains its contact with the outer periphery of the dust collar. Because of its light weight and self-lubricating characteristics, wear on this ring is negligible.

Provisions have been made on the gyratory crusher for the introduction of low pressure air to the dust seal chamber. This internal pressure, which can be obtained through the use of a small low pressure blower, creates an outward flow of air through the dust seal. This prevents an inward flow of abrasive dirt and dust. The combination of a highly effective sealing ring and the utilization of internal air pressure protects the eccentric and gears from destructive infiltration even under the most severe conditions. When required, this additional protection is supplied at a nominal additional cost.

All of the operating advantages all of the engineering and construction features described in this bulletin are found in both the primary and secondary gyratory crushers. Of course, certain modifications have been made to efficiently accomplish the tough, rugged job of secondary crushing. For instance, the secondary gyratory crusher has been engineered to accommodate the greater horsepower requirement of secondary crushing. Increased strength and durability have been built into all components.

In the past, primary crushers had to be set extremely close in order to provide an acceptable feed for secondary crushers. As a result, primary crushers were penalized by reduced capacity and excessive maintenance. The secondary gyratory crusher was engineered to solve this problem.

Anticipating product size variations, Allis-Chalmers has designed the secondary crusher with a large feed opening one large enough to accept oversized materials. This design feature is particularly advantageous when the secondary gyratory crusher follows a primary crusher that has no vertical adjustment for wear.

A large diameter crushing head along with tailored-to-your-operation design results in big capacity. An acute angle in the crushing chamber and a long parallel zone facilitate precision setting assure a cubical, well graded product distributes even the normal wear throughout the crushing chamber.

1. Spider cap 2. Spider 3. Hour glass bushing 4. Spider bearing oil seal 5. Spider bearing oil seal retainer 6. Spider bearing oil seal retainer screws 7. Spider joint bolts 8. Spider joint bolt nuts 9. Spider joint bolt lock nuts 10. Spider arm shield 11. Spider arm shield bolts 12. Spider arm shield bolt nuts 13. Center spider rim liners (not shown) 14. End spider rim liners 15. Rim liner bolts 16. Rim liner bolt nuts 17. Spider bearing spherical support ring 18. Spider bearing spherical support ring seat 19. Spider lubricating hose bushing 20. Spider lubricating hose 21. Spider lubricating hose bracket 22. Spider lubricating hose grease fitting 23. Spider lubricating hose bracket bolts 24. Spider joint studs (not shown) 26. Mainshaft thrust ring 27. Mainshaft thrust ring bolts 31. Top shell 32. Concave support ring 33. Upper concaves 34. Upper middle concaves 36. Lower middle concaves 37. Lower concaves 43. Bottom shell 44. Bottom shell joint bolts 45. Bottom shell joint bolt nuts 46. Bottom shell joint bolt lock nuts 47. Bottom shell bushing 48. Bottom shell bushing key 49. Bottom shell bushing clamp plate 50. Bottom shell bushing clamp plate bolts 51. Bottom shell front arm liners 52. Bottom shell rear arm liners 53. Bottom shell side liners 54. Bottom shell hub liners 55. Dust collar 56. Dust collar cap screws 57. Dust collar gasket 63. Bottom plate 64. Bottom plate studs 65. Bottom plate stud nuts 66. Bottom plate stud lock nuts 67. Bottom plate dowel pin 68. Bottom plate drain plug 69. Bottom plate gasket 95. Eccentric 96. Eccentric sleeve 97. Eccentric sleeve key 98. Bevel gear 99. Bevel gear key 100. Bevel gear key cap screws 101. Eccentric wearing plate 107. Mainshaft 108. Head center 109. Mantle lower section 110. Mantle upper section 111. Head nut 112. Dowel pin (for keying head nut to mantle) 113. Mainshaft sleeve 114. Adjusting nut 115. Adjusting nut collar 116. Enclosed ring type dust seal sealing ring 117. Enclosed ring type dust seal retaining ring 118. Enclosed ring type dust seal bolts 119. Adjusting nut tie bar 120. Adjusting nut tie bar bolts 121. Adjusting nut key 124. Pinion bearing housing 125. Pinion bearing housing gasket 126. Pinion bearing housing studs 127. Pinion bearing housing stud nuts 128. Pinion bearing housing stud lock nuts 129. Pinion bearing housing dowel pin 130. Pinion bearing housing oil drain plug 131. Pinion bearing housing oil level plug (not shown) 132. Pinion bearing housing oil filler plug 133. Pinionshaft 134. Drive sheave and bushing 135. Drive sheave key 136. Pinion shaft lock nut spacer 137. Pinion shaft lock nut spacer lockwasher 138. Pinion shaft lock nut spacer lockwasher gasket 139. Pinion bearing seal plate 140. Pinion bearing oil seal 141. Pinion bearing seal plate gaskets 142. Pinion bearing seal plate bolts 143. Pinionshaft outer bearing 144. Pinionshaft inner bearing 145. Pinionshaft bearing spacing collar 146. Pinionshaft bearing spacing collar gasket 147. Pinion 148. Pinion key 149. Pinion retainer plate 150. Pinion retainer plate bolts

In the dimension charts above, the first number in each size classification designates the size of the receiving opening in inches. The second number is the largest diameter of the mantle in inches. Primary crushers having the same mantle diameter use the same size bottom shell, gears, eccentrics and countershaft assemblies.

Secondary crushers use the same size bottom shells as certain size primary crushers, but different size top shells, mainshaft and spider assemblies. The 30-70 secondary gyratory crusher uses the bottom shell of the 42-65 primary crusher; the 24-60 secondary uses the 30-55 primary bottom shell.

Capacities given here are based on field data under average quarry conditions when crushing dry friable material equivalent to limestone. Because conditions of stone and methods of operation vary, capacities given are approximate only.

Where no capacity data is given the crusher is under development.Figures under Maximum Horsepower are correct only for throw and pinion Rpm given above. When speed is reduced, Maximum Horsepower must also be reduced proportionately.

This graph is based on customary practice and is principally a guide. Size of crusher may vary considerably with different materials, depending upon stratification, blockiness, quarry methods and size of quarry trucks. Pieces that cannot be handled by crusher without bridging should be broken in the quarry.

The screen analysis of the product from any crusher will vary widely, depending upon the character of the material, quarry conditions, and the amount of fines or product size in the initial feed at the time

the sample is taken. These factors should be taken into consideration when estimating the screen analysis of the crusher product. Product gradation curves based on many actual screen analyses have been prepared which can be used for estimating.

The crusher discharge opening on the open side will govern the product gradation from a crusher if corrected to take into consideration quarry or mine conditions, particularly as to the amount of fines in the crusher feed. The tabulation at the left is basedon an average of many screen analyses and gives the approximate percentage of product equal to the open side setting of the crusher. Its actual use when the feed conditions are definitely known should be corrected to take care of these conditions, particularly insofar as fines or product size in the feed are concerned. The curves on these pages have been prepared giving the approximate screen analysis of the crusher product and should be used in conjunction with Table I

Table I shows 90% of product should pass a 6-inch square opening flat testing sieve. Using the 90% vertical line on Table II, follow it up to the horizontal line of 6 inches. Follow the nearest curve to the intersection, and using this curve you will get the following approximate screen analysis.

Until recently, there has been no way of accurately determining the power required for agiven crushing operation. With little or no factualoperating data correlated into useful form, it wasdifficult even for the most experienced operators toarrive at a correct size crusher or a proper size crusher motor to do a given job.

The correlation of all this factual material, from extensive field operating data and laboratory data covering wide varieties of material, ranges of reduction sizes, and types of equipment, made it possible to establish a consistent common factor known asthe Work Index for accurately determining the power required for crushing.

In the Work Index method, frequently referred to as the Bond method, the Work Index is actually the total work input in kwhr per short ton required to reduce a given material from theoretically infinite particle size to 80% passing 100 microns or approximately 67% passing 200 mesh. Knowing the Work Index, you need only apply the given equation to determine power input required. The calculated power input enables you to select the proper crusher.

In order to simplify the selection of a crusher by the Work Index method, the following form has been developed. References below the form explain the various parts of the calculation, and, immediately below, a complete example is worked out.

REFERENCE I Average Impact. As noted, the Work Index is determined from the average impact value and the specific gravity of the material being crushed. The impact value and Work Index can be determined in the Processing Machinery Laboratory, or these values can be determined from a comparable operation in the field. Acomplete listing of Work Indexes of materials which have been tested in the laboratory.

REFERENCE II Feed Size. In the case of a primary crusher this may be somewhat difficult to obtain. Experience indicates, however, that in most cases 80% of the feed size will pass a square opening equal to from half to two-thirds of the crusher receiving opening.

A crushed stone producer desires a primary crusher to handle the product from a 3-yard shovel at an average rate of 350 tph. The rated capacity of the crusher must, of course, be greater than this because of inevitable quarrying and crushing delays. A crusher setting of 5 in. on the open side is desired because of following equipment and the requirements for stone.

MATERIAL: Limestone WORK INDEX 10.7 CRUSHER: 42-65 Primary gyratory Open Side Setting: 5; Eccentric Throw: 1 Recommended Operating Speed; 400 Rpm (Approximately 80% of Maximum Speed) Capacity at Recommended Speed: 438 Short Ton/Hour Maximum Horsepower Allowable at Selected Throw and Speed: 213 Horsepower. FEED SIZE: (F) 80% Passes 28 (66% of Feed Opening) F 711,000 Microns F = 842 PRODUCT SIZE: (P) 80% Passes 4, P = 108,000 Microns P = 328 F P = 514 HORSEPOWER/SHORT TON = 10.7 x 13.4 x 514/842 x 328 = .267 .267 Horsepower/Short Ton x438 Short Tons/Hour Capacity = 117Horsepower Required RECOMMENDED MOTOR SIZE: 150 Horsepower Motor.

Tabulated data presented has been compiled from tests made in the Allis-Chalmers Research Laboratory. This data is a cross section of impact and compressive strength tests made on hundreds of different rock samples for customers in the U.S. and abroad.

Ten or more representative pieces of broken stone, each of which passes a square opening three inches on a side and will not pass a two-inch square, are selected and broken individually between two 30-lb pendulum hammers. The hammers are raised by an equal amount and released simultaneously. This is repeated with successively greater angles of fall until the specimen breaks. Its impact strength is the average foot-pounds of energy represented by the breaking fall divided by the thickness in inches. The average impact strength is the average foot-pounds per inch required to break the ten or more pieces, and the maximum is the foot-pounds per inch required to break the hardest piece, the highest value obtained.

The compressive strengths of many materials have been measured in the Laboratory by cutting samples into one-inch cubes which are then broken under slow compression in a Southwark compression tester. This indicates the compressive strength in pounds per square inch.

The correlation between the compressive strengthand the impact crushing strength is inconsistent, and experiencehas shown that theimpact strength is abetter criterion of theactual resistance tocrushing. The impactdevice more nearly approaches actual crusher operation, both invelocity of impact andin the fact that broken stone is used intesting.

The average impactcrushing strength isan indication of theenergy required forcrushing, while themaximum compression values indicate the danger of crusher breakage and the type of construction necessary. Crusher capacities do not vary greatly with the impact strength. There is a capacity increase of less than 10% from the hardest to the softest stone, where packing is not a factor.

crushers - all crusher types for your reduction needs - metso outotec

crushers - all crusher types for your reduction needs - metso outotec

All rock crushers can be classified as falling into two main groups. Compressive crushers that press the material until it breaks, and impact crushers using the principle of quick impacts to crush the material. Jaw crushers, gyratory crushers, and cone operate according to the compression principle. Impact crushers, in turn, utilize the impact principle.

As the name suggest, jaw crushers reduce rock and other materials between a fixed and a moving jaw. The moving jaw is mounted on a pitman that has a reciprocating motion, and the fixed jaw stays put. When the material runs between the two jaws, the jaws compress larger boulders into smaller pieces.

There are two basic types of jaw crushers: single toggle and double toggle. In the single toggle jaw crusher, an eccentric shaft is on the top of the crusher. Shaft rotation causes, along with the toggle plate, a compressive action.

The chewing movement, which causes compression at both material intake and discharge, gives the single toggle jaw better capacity, compared to a double toggle jaw of similar size. Metsos jaw crushers are all single toggle.

Gyratory crushers have an oscillating shaft. The material is reduced in a crushing cavity, between an external fixed element (bowl liner) and an internal moving element (mantle) mounted on the oscillating shaft assembly.

The fragmentation of the material results from the continuous compression that takes place between the liners around the chamber. An additional crushing effect occurs between the compressed particles, resulting in less wear of the liners.

Cone crushers resemble gyratory crushers from technological standpoint, but unlike gyratory crushers, cone crushers are popular in secondary, tertiary, and quaternary crushing stages. Sometimes, however, the grain size of the processed material is small enough by nature and the traditional primary crushing stage is not needed. In these cases, also cone crushers can carry out the first stage of the crushing process.

Cone crushers have an oscillating shaft, and the material is crushed in a crushing cavity, between an external fixed element (bowl liner) and an internal moving element (mantle) mounted on the oscillating shaft assembly.

An eccentric shaft rotated by a gear and pinion produces the oscillating movement of the main shaft. The eccentricity causes the cone head to oscillate between open side setting and closed side setting discharge opening.

The fragmentation of the material results from the continuous compression that takes place between the liners around the chamber. An additional crushing effect occurs between the compressed particles, resulting in less wear of the liners. This is called interparticular crushing also.

Depending on cone crusher, setting can be adjusted in two ways. The first way is for setting adjustment to be done by rotating the bowl against the threads so that the vertical position of the outer wear part (concave) is changed. One advantage of this adjustment type is that liners wear more evenly.

To optimize operating costs and improve the product shape it is recommended that cone crushers are always be choke fed, meaning that the cavity should be as full of rock material as possible. This can be easily achieved by using a stockpile or a silo to regulate the inevitable fluctuation of feed material flow. Level monitoring devices detect the maximum and minimum levels of the material, starting and stopping the feed of material to the crusher, as needed.

Impact crushers are traditionally classified to two main types: horizontal shaft impact (HSI) crushers and vertical shaft impact (VSI) crushers. These different types of impact crushers share the crushing principle, impact, to reduce the material to smaller sizes, but features, capacities and optimal applications are far from each other.

Horizontal shaft impact (HSI) crushers are used in primary, secondary or tertiary crushing stage. HSI crushers reduce the feed material by highly intensive impacts originating in the quick rotational movement of hammers or bars fixed to the rotor. The particles produced are then further fragmentated inside the crusher as they collide against crusher chamber and each other, producing a finer, better-shaped product.

VSI crusher can be considered a stone pump that operates like a centrifugal pump. The material is fed through the center of the rotor, where it is accelerated to high speed before being discharged through openings in the rotor periphery. The material is crushed as it hits of the outer body at high speed and due to rocks colliding against each other.

Selecting optimal crushing equipment can be difficult. Luckily there are tools and software available that simplify weighting different options and help in making decisions. The backbone of all these analyzes are careful calculations that take into account the capabilities and constraints of different crushers and operational requirements.

Every crushing site and operation is different, and theoptimal results are normally obtained by combining theoretical conclusions with practical experience of different materials, operational conditions, maintenance needs, and economic aspects of various alternatives.

Below are some key issues listed according to crushing stages in brief. While defining the best technical solution for your requirements, its good to remember that many crushers are available not only as stationary but also asmobileorportableversions in case you prefer to move or transport your crusher at the production site or between sites regularly.

If you are interested in more detailed analyzes tailored just for your crushing operations, please contact Metso experts. We have practical experience of thousands of different crushing applications around the world, and we are happy to help in finding the equipment that best fits your needs.

The main purpose of a primary crusher is to reduce the material to a size that allows its transportation on a conveyor belt. In most crushing installations a jaw crusher takes care of primary crushing. Plants with very high capacities that are common in mining and less popular in aggregates production, normally use a primary gyratory crusher. When the processed material is easy to crush and not very abrasive, an impact crusher may be the best choice for primary crushing.

One of the most important characteristics of a primary crusher is its capacity for accepting feed material without bridging. A large primary crusher is, naturally, more expensive than a smaller one. Therefore, the investment cost calculations for primary crushers are compared together against the total costs of primary stages, including quarry face clearing, blasting, and drilling costs. In many cases, dump trucks transport the rock to a stationary primary crusher. This may be an expensive solution. Amortization, fuel, tires, and maintenance costs can be included when the vehicles are in high demand. In modern aggregates operations, the use of mobile primary crushers that can move alongside the rock face is, in many cases, the most economical solution.

In terms of the size of the feed opening, the client gets a better return on investment when the primary crusher is a jaw crusher. That means less drilling and blasting because the crusher accepts larger boulders. The disadvantage of this type of crusher, when high capacity is required, is the relatively small discharge width, limiting the capacity as compared with the discharge circuit of a gyratory crusher. Jaw crushers are mainly used in plants producing up to approximately 1600 t/h.

The primary gyratory crusher offers high capacity thanks to its generously dimensioned circular discharge opening (which provides a much larger area than that of the jaw crusher) and the continuous operation principle (while the reciprocating motion of the jaw crusher produces a batch crushing action). The gyratory crusher has no rival in large plants with capacities starting from 1200 t/h and above. To have a feed opening corresponding to that of a jaw crusher, the primary gyratory crusher must be much taller and heavier. Also, primary gyratories require quite a massive foundation.

The primary impact crusher offers high capacity and is designed to accept large feed sizes. The primary impact crushers are used to process from 200 t/h up to 1900 t/h and feed sizes of up to 1830 mm (71") in the largest model. Primary impact crushers are generally used in nonabrasive applications and where the production of fines is not a problem. Of all primary crushers, the impactor is the crusher that gives the best cubical product.

If the intermediate crushing is done with the purpose of producing railway ballast, the quality of the product is important. In other cases, there normally are no quality requirements, except that the product be suitable for fine crushing.

Due to their design, cone crushers are generally a more expensive investment than impactors are. However, when correctly used, a cone crusher offers lower operating costs than a conventional impact crusher. Therefore, clients crushing hard or abrasive materials are advised to install cone crushers for the final crushing and cubicising stage.

Cone crushers can in most cases also give a good cubic shape to fine grades. They can be adapted to different applications. This is an important factor, as client-specific needs often change during a crushers lifetime.

The conventional type has horizontal shaft configuration, known as HSI. The other type consists of a centrifugal crusher with vertical shaft, generally known as VSI. Impactor operation is based on the principle of rapid transfer of impact energy to the rock material. Impactors produce cubic products, and they can offer high reduction ratios as long as the feed material is not too fine. This means that in certain cases it is possible to use a single impact crusher to carry out a task normally done in several crushing stages using compressing crushers (i.e., jaw, gyratory, and/or cone crushers). Impactors are mostly used for nonabrasive materials.

Conventional horizontal-shaft impact crushers are available in various sizes and models, from high-capacity primary crushers for large limestone quarries to specially designed machines for the crushing of materials such as slag.

There are two main categories of VSI crushers machines with impact wear parts around the body and machines that use a layer of accumulated material. The first type is in many respects similar to the conventional impactor with horizontal shaft and rotor. The second type became quite popular in the past decade and is known as the Barmac crusher. The difference between a conventional impactor and a VSI of the Barmac type is that the latter offers lower operating costs, but its reduction ratio is lower also. In a Barmac VSI, the material undergoes an intense rock-on-rock crushing process. In the other crushers, most of the reduction is done by the impact of stone against metal.

Customers operating old, rebuilt, or expanded plants often have problems with the shape of the product. In these cases, the addition of a Barmac VSI in the final crushing stage offers a solution to product shape problems.

The same applies to many mobile crushing units. As the number of crushing stages is normally small with this type of plant, it is almost impossible to obtain a good product shape unless the rock is relatively soft and thus more suited for the production of cubic product. A centrifugal crusher in the final stage can help to solve the problem.

Get the maximum potential out of your size reduction process to achieve improved crushing performance and lower cost per ton. By using our unique simulation software, our Chamber Optimization experts can design an optimized crushing chamber that matches the exact conditions under which you operate.

gyratory crusher - an overview | sciencedirect topics

gyratory crusher - an overview | sciencedirect topics

Gyratory crushers were invented by Charles Brown in 1877 and developed by Gates around 1881 and were referred to as a Gates crusher [1]. The smaller form is described as a cone crusher. The larger crushers are normally known as primary crushers as they are designed to receive run-on-mine (ROM) rocks directly from the mines. The gyratory crushers crush to reduce the size by a maximum of about one-tenth its size. Usually, metallurgical operations require greater size reduction; hence, the products from the primary crushers are conveyed to secondary or cone crushers where further reduction in size takes place. Here, the maximum reduction ratio is about 8:1. In some cases, installation of a tertiary crusher is required where the maximum reduction is about 10:1. The secondary crushers are also designed on the principle of gyratory crushing, but the construction details vary.

Similar to jaw crushers, the mechanism of size reduction in gyratory crushers is primarily by the compressive action of two pieces of steel against the rock. As the distance between the two plates decreases continuous size reduction takes place. Gyratory crushers tolerate a variety of shapes of feed particles, including slabby rock, which are not readily accepted in jaw crushers because of the shape of the feed opening.

The gyratory crusher shown in Figure 2.6 employs a crushing head, in the form of a truncated cone, mounted on a shaft, the upper end of which is held in a flexible bearing, whilst the lower end is driven eccentrically so as to describe a circle. The crushing action takes place round the whole of the cone and, since the maximum movement is at the bottom, the characteristics of the machine are similar to those of the Stag crusher. As the crusher is continuous in action, the fluctuations in the stresses are smaller than in jaw crushers and the power consumption is lower. This unit has a large capacity per unit area of grinding surface, particularly if it is used to produce a small size reduction. It does not, however, take such a large size of feed as a jaw crusher, although it gives a rather finer and more uniform product. Because the capital cost is high, the crusher is suitable only where large quantities of material are to be handled.

However, the gyratory crusher is sensitive to jamming if it is fed with a sticky or moist product loaded with fines. This inconvenience is less sensitive with a single-effect jaw crusher because mutual sliding of grinding surfaces promotes the release of a product that adheres to surfaces.

The profile of active surfaces could be curved and studied as a function of the product in a way to allow for work performed at a constant volume and, as a result, a higher reduction ratio that could reach 20. Inversely, at a given reduction ratio, effective streamlining could increase the capacity by 30%.

Maintenance of the wear components in both gyratory and cone crushers is one of the major operating costs. Wear monitoring is possible using a Faro Arm (Figure 6.10), which is a portable coordinate measurement machine. Ultrasonic profiling is also used. A more advanced system using a laser scanner tool to profile the mantle and concave produces a 3D image of the crushing chamber (Erikson, 2014). Some of the benefits of the liner profiling systems include: improved prediction of mantle and concave liner replacement; identifying asymmetric and high wear areas; measurement of open and closed side settings; and quantifying wear life with competing liner alloys.

Crushers are widely used as a primary stage to produce the particulate product finer than about 50100mm. They are classified as jaw, gyratory, and cone crushers based on compression, cutter mill based on shear, and hammer crusher based on impact.

A jaw crusher consists essentially of two crushing plates, inclined to each other forming a horizontal opening by their lower borders. Material is crushed between a fixed and a movable plate by reciprocating pressure until the crushed product becomes small enough to pass through the gap between the crushing plates. Jaw crushers find a wide application for brittle materials. For example, they are used for comminution of porous copper cake. A Fritsch jaw crusher with maximal feed size 95mm, final fineness (depends on gap setting) 0.315mm, and maximal continuous throughput 250Kg/h is shown in Fig. 2.8.

A gyratory crusher includes a solid cone set on a revolving shaft and placed within a hollow body, which has conical or vertical sloping sides. Material is crushed when the crushing surfaces approach each other and the crushed products fall through the discharging opening.

Hammer crushers are used either as a one-step primary crusher or as a secondary crusher for products from a primary crusher. They are widely used for crushing hard metal scrap for different hard metal recycling processes. Pivoted hammers are pendulous, mounted on the horizontal axes symmetrically located along the perimeter of a rotor. Crushing takes place by the impact of material pieces with the high speed moving hammers and by contact with breaker plates. A cylindrical grating or screen is placed beneath the rotor. Materials are reduced to a size small enough to pass through the openings of the grating or screen. The size of the product can be regulated by changing the spacing of the grate bars or the opening of the screen.

The feature of the hammer crushers is the appearance of elevated pressure of air in the discharging unit of the crusher and underpressure in the zone around the shaft close to the inside surface of the body side walls. Thus, the hammer crushers also act as high-pressure, forced-draught fans. This may lead to environmental pollution and product losses in fine powder fractions. A design for a hammer crusher (Fig. 2.9) essentially allows a decrease of the elevated pressure of air in the crusher discharging unit [5]. The A-zone beneath the screen is communicated through the hollow ribs and openings in the body side walls with the B-zone around the shaft close to the inside surface of body side walls. As a result, the circulation of suspended matter in the gas between A and B zones is established and the high pressure of air in the discharging unit of crusher is reduced.

Crushers are widely used as a primary stage to produce the particulate product finer than about 50100 mm in size. They are classified as jaw, gyratory and cone crushers based on compression, cutter mill based on shear and hammer crusher based on impact.

A jaw crusher consists essentially of two crushing plates, inclined to each other forming a horizontal opening by their lower borders. Material is crushed between a fixed and a movable plate by reciprocating pressure until the crushed product becomes small enough to pass through the gap between the crushing plates. Jaw crushers find a wide application for brittle materials. For example, they are used for comminution of porous copper cake.

A gyratory crusher includes a solid cone set on a revolving shaft and placed within a hollow body, which has conical or vertical sloping sides. Material is crushed when the crushing surfaces approach each other and the crushed products fall through the discharging opening.

Hammer crushers are used either as a one-step primary crusher or as a secondary crusher for products from a primary crusher. They are widely used for crushing of hard metal scrap for different hard metal recycling processes.

Pivoted hammers are pendulous, mounted on the horizontal axes symmetrically located along the perimeter of a rotor and crushing takes place by the impact of material pieces with the high speed moving hammers and by contact with breaker plates. A cylindrical grating or screen is placed beneath the rotor. Materials are reduced to a size small enough pass through the openings of the grating or screen. The size of product can be regulated by changing the spacing of the grate bars or the opening of the screen.

The feature of the hammer crushers is the appearance of elevated pressure of air in the discharging unit of the crusher and underpressure in the zone around of the shaft close to the inside surface of the body side walls. Thus, the hammer crushers also act as high-pressure forced-draught fans. This may lead to environmental pollution and product losses in fine powder fractions.

A design for a hammer crusher (Figure 2.6) allows essentially a decrease of the elevated pressure of air in the crusher discharging unit [5]. The A-zone beneath the screen is communicated through the hollow ribs and openings in the body side walls with the B-zone around the shaft close to the inside surface of body side walls. As a result, circulation of suspended matter in the gas between A- and B-zones is established and high pressure of air in the discharging unit of crusher is reduced.

Jaw crushers are mainly used as primary crushers to produce material that can be transported by belt conveyors to the next crushing stages. The crushing process takes place between a fixed jaw and a moving jaw. The moving jaw dies are mounted on a pitman that has a reciprocating motion. The jaw dies must be replaced regularly due to wear. Figure 8.1 shows two basic types of jaw crushers: single toggle and double toggle. In the single toggle jaw crusher, an eccentric shaft is installed on the top of the crusher. Shaft rotation causes, along with the toggle plate, a compressive action of the moving jaw. A double toggle crusher has, basically, two shafts and two toggle plates. The first shaft is a pivoting shaft on the top of the crusher, while the other is an eccentric shaft that drives both toggle plates. The moving jaw has a pure reciprocating motion toward the fixed jaw. The crushing force is doubled compared to single toggle crushers and it can crush very hard ores. The jaw crusher is reliable and robust and therefore quite popular in primary crushing plants. The capacity of jaw crushers is limited, so they are typically used for small or medium projects up to approximately 1600t/h. Vibrating screens are often placed ahead of the jaw crushers to remove undersize material, or scalp the feed, and thereby increase the capacity of the primary crushing operation.

Both cone and gyratory crushers, as shown in Figure 8.2, have an oscillating shaft. The material is crushed in a crushing cavity, between an external fixed element (bowl liner) and an internal moving element (mantle) mounted on the oscillating shaft assembly. An eccentric shaft rotated by a gear and pinion produces the oscillating movement of the main shaft. The eccentricity causes the cone head to oscillate between the open side setting (o.s.s.) and closed side setting (c.s.s.). In addition to c.s.s., eccentricity is one of the major factors that determine the capacity of gyratory and cone crushers. The fragmentation of the material results from the continuous compression that takes place between the mantle and bowl liners. An additional crushing effect occurs between the compressed particles, resulting in less wear of the liners. This is also called interparticle crushing. The gyratory crushers are equipped with a hydraulic setting adjustment system, which adjusts c.s.s. and thus affects product size distribution. Depending on cone type, the c.s.s. setting can be adjusted in two ways. The first way is by rotating the bowl against the threads so that the vertical position of the outer wear part (concave) is changed. One advantage of this adjustment type is that the liners wear more evenly. Another principle of setting adjustment is by lifting/lowering the main shaft. An advantage of this is that adjustment can be done continuously under load. To optimize operating costs and improve the product shape, as a rule of thumb, it is recommended that cones always be choke-fed, meaning that the cavity should be as full of rock material as possible. This can be easily achieved by using a stockpile or a silo to regulate the inevitable fluctuation of feed material flow. Level monitoring devices that detect the maximum and minimum levels of the material are used to start and stop the feed of material to the crusher as needed.

Primary gyratory crushers are used in the primary crushing stage. Compared to the cone type crusher, a gyratory crusher has a crushing chamber designed to accept feed material of a relatively large size in relation to the mantle diameter. The primary gyratory crusher offers high capacity thanks to its generously dimensioned circular discharge opening (which provides a much larger area than that of the jaw crusher) and the continuous operation principle (while the reciprocating motion of the jaw crusher produces a batch crushing action). The gyratory crusher has capacities starting from 1200 to above 5000t/h. To have a feed opening corresponding to that of a jaw crusher, the primary gyratory crusher must be much taller and heavier. Therefore, primary gyratories require quite a massive foundation.

The cone crusher is a modified gyratory crusher. The essential difference is that the shorter spindle of the cone crusher is not suspended, as in the gyratory, but is supported in a curved, universal bearing below the gyratory head or cone (Figure 8.2). Power is transmitted from the source to the countershaft to a V-belt or direct drive. The countershaft has a bevel pinion pressed and keyed to it and drives the gear on the eccentric assembly. The eccentric assembly has a tapered, offset bore and provides the means whereby the head and main shaft follow an eccentric path during each cycle of rotation. Cone crushers are used for intermediate and fine crushing after primary crushing. The key factor for the performance of a cone type secondary crusher is the profile of the crushing chamber or cavity. Therefore, there is normally a range of standard cavities available for each crusher, to allow selection of the appropriate cavity for the feed material in question.

Depending on the size of the debris, it may either be ready to enter the recycling process or need to be broken down to obtain a product with workable particle sizes, in which case hydraulic breakers mounted on tracked or wheeled excavators are used. In either case, manual sorting of large pieces of steel, wood, plastics and paper may be required, to minimise the degree of contamination of the final product.

The three types of crushers most commonly used for crushing CDW materials are the jaw crusher, the impact crusher and the gyratory crusher (Figure 4.4). A jaw crusher consists of two plates, with one oscillating back and forth against the other at a fixed angle (Figure 4.4(a)) and it is the most widely used in primary crushing stages (Behera etal., 2014). The jaw crusher can withstand large and hard-to-break pieces of reinforced concrete, which would probably cause the other crushing machines to break down. Therefore, the material is initially reduced in jaw crushers before going through any other crushing operation. The particle size reduction depends on the maximum and minimum size of the gap at the plates (Hansen, 2004).

An impact crusher breaks the CDW materials by striking them with a high-speed rotating impact, which imparts a shearing force on the debris (Figure 4.4(b)). Upon reaching the rotor, the debris is caught by steel teeth or hard blades attached to the rotor. These hurl the materials against the breaker plate, smashing them into smaller particle sizes. Impact crushers provide better grain-size distribution of RA for road construction purposes, and they are less sensitive to material that cannot be crushed, such as steel reinforcement.

Generally, jaw and impact crushers exhibit a large reduction factor, defined as the ratio of the particle size of the input to that of the output material. A jaw crusher crushes only a small proportion of the original aggregate particles but an impact crusher crushes mortar and aggregate particles alike and thus generates a higher amount of fine material (OMahony, 1990).

Gyratory crushers work on the same principle as cone crushers (Figure 4.4(c)). These have a gyratory motion driven by an eccentric wheel. These machines will not accept materials with a large particle size and therefore only jaw or impact crushers should be considered as primary crushers. Gyratory and cone crushers are likely to become jammed by fragments that are too large or too heavy. It is recommended that wood and steel be removed as much as possible before dumping CDW into these crushers. Gyratory and cone crushers have advantages such as relatively low energy consumption, a reasonable amount of control over the particle size of the material and production of low amounts of fine particles (Hansen, 2004).

For better control of the aggregate particle size distribution, it is recommended that the CDW should be processed in at least two crushing stages. First, the demolition methodologies used on-site should be able to reduce individual pieces of debris to a size that the primary crusher in the recycling plant can take. This size depends on the opening feed of the primary crusher, which is normally bigger for large stationary plants than for mobile plants. Therefore, the recycling of CDW materials requires careful planning and communication between all parties involved.

A large proportion of the product from the primary crusher can result in small granules with a particle size distribution that may not satisfy the requirements laid down by the customer after having gone through the other crushing stages. Therefore, it should be possible to adjust the opening feed size of the primary crusher, implying that the secondary crusher should have a relatively large capacity. This will allow maximisation of coarse RA production (e.g., the feed size of the primary crusher should be set to reduce material to the largest size that will fit the secondary crusher).

The choice of using multiple crushing stages mainly depends on the desired quality of the final product and the ratio of the amounts of coarse and fine fractions (Yanagi etal., 1998; Nagataki and Iida, 2001; Nagataki etal., 2004; Dosho etal., 1998; Gokce etal., 2011). When recycling concrete, a greater number of crushing processes produces a more spherical material with lower adhered mortar content (Pedro etal., 2015), thus providing a superior quality of material to work with (Lotfi etal., 2017). However, the use of several crushing stages has some negative consequences as well; in addition to costing more, the final product may contain a greater proportion of finer fractions, which may not always be a suitable material.

The first step of physical beneficiation is crushing and grinding the iron ore to its liberation size, the maximum size where individual particles of gangue are separated from the iron minerals. A flow sheet of a typical iron ore crushing and grinding circuit is shown in Figure 1.2.2 (based on Ref. [4]). This type of flow sheet is usually followed when the crude ore contains below 30% iron. The number of steps involved in crushing and grinding depends on various factors such as the hardness of the ore and the level of impurities present [5].

Jaw and gyratory crushers are used for initial size reduction to convert big rocks into small stones. This is generally followed by a cone crusher. A combination of rod mill and ball mills are then used if the ore must be ground below 325 mesh (45m). Instead of grinding the ore dry, slurry is used as feed for rod or ball mills, to avoid dusting. Oversize and undersize materials are separated using a screen; oversize material goes back for further grinding.

Typically, silica is the main gangue mineral that needs to be separated. Iron ore with high-silica content (more than about 2%) is not considered an acceptable feed for most DR processes. This is due to limitations not in the DR process itself, but the usual customer, an EAF steelmaking shop. EAFs are not designed to handle the large amounts of slag that result from using low-grade iron ores, which makes the BF a better choice in this situation. Besides silica, phosphorus, sulfur, and manganese are other impurities that are not desirable in the product and are removed from the crude ore, if economically and technically feasible.

Beneficiation of copper ores is done almost exclusively by selective froth flotation. Flotation entails first attaching fine copper mineral particles to bubbles rising through an orewater pulp and, second, collecting the copper minerals at the top of the pulp as a briefly stable mineralwaterair froth. Noncopper minerals do not attach to the rising bubbles; they are discarded as tailings. The selectivity of the process is controlled by chemical reagents added to the pulp. The process is continuous and it is done on a large scale103 to 105 tonnes of ore feed per day.

Beneficiation is begun with crushing and wet-grinding the ore to typically 10100m. This ensures that the copper mineral grains are for the most part liberated from the worthless minerals. This comminution is carried out with gyratory crushers and rotary grinding mills. The grinding is usually done with hard ore pieces or hard steel balls, sometimes both. The product of crushing and grinding is a waterparticle pulp, comprising 35% solids.

Flotation is done immediately after grindingin fact, some flotation reagents are added to the grinding mills to ensure good mixing and a lengthy conditioning period. The flotation is done in large (10100m3) cells whose principal functions are to provide: clouds of air bubbles to which the copper minerals of the pulp attach; a means of overflowing the resulting bubblecopper mineral froth; and a means of underflowing the unfloated material into the next cell or to the waste tailings area.

Selective attachment of the copper minerals to the rising air bubbles is obtained by coating the particles with a monolayer of collector molecules. These molecules usually have a sulfur atom at one end and a hydrophobic hydrocarbon tail at the other (e.g., potassium amyl xanthate). Other important reagents are: (i) frothers (usually long-chain alcohols) which give a strong but temporary froth; and (ii) depressants (e.g., CaO, NaCN), which prevent noncopper minerals from floating.

cone crusher - an overview | sciencedirect topics

cone crusher - an overview | sciencedirect topics

Cone crushers were originally designed and developed by Symons around 1920 and therefore are often described as Symons cone crushers. As the mechanisms of crushing in these crushers are similar to gyratory crushers their designs are similar, but in this case the spindle is supported at the bottom of the gyrating cone instead of being suspended as in larger gyratory crushers. Figure5.3 is a schematic diagram of a cone crusher.

The breaking head gyrates inside an inverted truncated cone. These crushers are designed so that the head-to-depth ratio is larger than the standard gyratory crusher and the cone angles are much flatter and the slope of the mantle and the concaves are parallel to each other. The flatter cone angles help to retain the particles longer between the crushing surfaces and therefore produce much finer particles. To prevent damage to the crushing surfaces, the concave or shell of the crushers is held in place by strong springs or hydraulics which yield to permit uncrushable tramp material to pass through.

The secondary crushers are designated as Standard cone crushers having stepped liners and tertiary Short Head cone crushers, which have smoother crushing faces and steeper cone angles of the breaking head. The approximate distance of the annular space at the discharge end designates the size of the cone crushers. A brief summary of the design characteristics is given in Table5.4 for crusher operation in open-circuit and closed-circuit situations.

The Standard cone crushers are for normal use. The Short Head cone crushers are designed for tertiary or quaternary crushing where finer product is required. These crushers are invariably operated in closed circuit. The final product sizes are fine, medium or coarse depending on the closed set spacing, the configuration of the crushing chamber and classifier performance, which is always installed in parallel.

For finer product sizes, i.e., less than 6mm, special cone crushers known as Gyradisc crushers are available. The operation is similar to the standard cone crushers, except that the size reduction is caused more by attrition than by impact [5]. The reduction ratio is around 8:1 and as the product size is relatively small the feed size is limited to less than 50mm with a nip angle between 25 and 30. The Gyradisc crushers have head diameters from around 900 to 2100mm. These crushers are always operated under choke feed conditions. The feed size is less than 50mm and therefore the product size is usually less than 69mm.

Maintenance of the wear components in both gyratory and cone crushers is one of the major operating costs. Wear monitoring is possible using a Faro Arm (Figure 6.10), which is a portable coordinate measurement machine. Ultrasonic profiling is also used. A more advanced system using a laser scanner tool to profile the mantle and concave produces a 3D image of the crushing chamber (Erikson, 2014). Some of the benefits of the liner profiling systems include: improved prediction of mantle and concave liner replacement; identifying asymmetric and high wear areas; measurement of open and closed side settings; and quantifying wear life with competing liner alloys.

Various types of rock fracture occur at different loading rates. For example, rock destruction by a boring machine, a jaw or cone crusher, and a grinding roll machine are within the extent of low loading rates, often called quasistatic loading condition. On the contrary, rock fracture in percussive drilling and blasting happens under high loading rates, usually named dynamic loading condition. This chapter presents loading rate effects on rock strengths, rock fracture toughness, rock fragmentation, energy partitioning, and energy efficiency. Finally, some of engineering applications of loading rate effects are discussed.

In Chapter4, we have already seen the mechanism of crushing in a jaw crusher. Considering it further we can see that when a single particle, marked 1 in Figure11.5a, is nipped between the jaws of a jaw crusher the particle breaks producing fragments, marked 2 and 3 in Figure11.5b. Particles marked 2 are larger than the open set on the crusher and are retained for crushing on the next cycle. Particles of size 3, smaller than the open set of the crusher, can travel down faster and occupy or pass through the lower portion of the crusher while the jaw swings away. In the next cycle the probability of the larger particles (size 2) breaking is greater than the smaller sized particle 3. In the following cycle, therefore, particle size 2 is likely to disappear preferentially and the progeny joins the rest of thesmaller size particles indicated as 3 in Figure11.5c. In the figures, the position of the crushed particles that do not exist after comminution is shaded white (merely to indicate the positions they had occupied before comminution). Particles that have been crushed and travelled down are shown in grey. The figure clearly illustrates the mechanism of crushing and the classification that takes place within the breaking zone during the process, as also illustrated in Figure11.4. This type of breakage process occurs within a jaw crusher, gyratory crusher, roll crusher and rod mills. Equation (11.19) then is a description of the crusher model.

In practice however, instead of a single particle, the feed consists of a combination of particles present in several size fractions. The probability of breakage of some relatively larger sized particles in preference to smaller particles has already been mentioned. For completeness, the curve for the probability of breakage of different particle sizes is again shown in Figure11.6. It can be seen that for particle sizes ranging between 0 K1, the probability of breakage is zero as the particles are too small. Sizes between K1 and K2 are assumed to break according a parabolic curve. Particle sizes greater than K2 would always be broken. According to Whiten [16], this classification function Ci, representing the probability of a particle of size di entering the breakage stage of the crusher, may be expressed as

The classification function can be readily expressed as a lower triangular matrix [1,16] where the elements represent the proportion of particles in each size interval that would break. To construct a mathematical model to relate product and feed sizes where the crusher feed contains a proportion of particles which are smaller than the closed set and hence will pass through the crusher with little or no breakage, Whiten [16] advocated a crusher model as shown in Figure11.7.

The considerations in Figure11.7 are similar to the general model for size reduction illustrated in Figure11.4 except in this case the feed is initially directed to a classifier, which eliminates particle sizes less than K1. The coarse classifier product then enters the crushing zone. Thus, only the crushable larger size material enters the crusher zone. The crusher product iscombined with the main feed and the process repeated. The undersize from the classifier is the product.

While considering the above aspects of a model of crushers, it is important to remember that the size reduction process in commercial operations is continuous over long periods of time. In actual practice, therefore, the same operation is repeated over long periods, so the general expression for product size must take this factor into account. Hence, a parameter v is introduced to represent the number of cycles of operation. As all cycles are assumed identical the general model given in Equation (11.31) should, therefore, be modified as

Multiple vectors B C written in matrix form:BC=0.580000.200.60000.120.180.6100.040.090.20.571.000000.700000.4500000=0581+00+00+000.580+00.7+00+000580+00+00.45+000.580+00+00+000.21+0.60+00+000.20+0.60.7+00+000.20+0.60+00.45+000.20+0.60+00+000.121+0.180+0.610+000.120+0.180.7+0.610+000.120+0.180+0.610.45+000.120+0.180+0.610+000.041+0.090+0.20+0.5700.040+0.090.7+0.20+0.5700.040+0.090+0.20.45+0.5700.040+0.090+0.20+0.570=0.580000.20.42000.120.1260.274500.040.0630.090

Now determine (I B C) and (I C)(IBC)=10.5800000000.210.42000000.1200.12610.27450000.0400.06300.0910=0.420000.20.58000.120.1260.725500.040.0630.091and(IC)=000000.300000.5500001

Now find the values of x1, x2, x3 and x4 as(0.42x1)+(0x2)+(0x3)+(0x4)=10,thereforex1=23.8(0.2x1)+(0.58x2)+(0x3)+(0x4)=33,thereforex2=65.1(0.12x1)+(0.126x2)+(0.7255x3)+(0x4)=32,thereforex3=59.4(0.04x1)+(0.063x2)+(0.09x3)+(1x4)=20,thereforex4=30.4

In this process, mined quartz is crushed into pieces using crushing/smashing equipment. Generally, the quartz smashing plant comprises a jaw smasher, a cone crusher, an impact smasher, a vibrating feeder, a vibrating screen, and a belt conveyor. The vibrating feeder feeds materials to the jaw crusher for essential crushing. At that point, the yielding material from the jaw crusher is moved to a cone crusher for optional crushing, and afterward to effect for the third time crushing. As part of next process, the squashed quartz is moved to a vibrating screen for sieving to various sizes.

Crushers are widely used as a primary stage to produce the particulate product finer than about 50100mm. They are classified as jaw, gyratory, and cone crushers based on compression, cutter mill based on shear, and hammer crusher based on impact.

A jaw crusher consists essentially of two crushing plates, inclined to each other forming a horizontal opening by their lower borders. Material is crushed between a fixed and a movable plate by reciprocating pressure until the crushed product becomes small enough to pass through the gap between the crushing plates. Jaw crushers find a wide application for brittle materials. For example, they are used for comminution of porous copper cake. A Fritsch jaw crusher with maximal feed size 95mm, final fineness (depends on gap setting) 0.315mm, and maximal continuous throughput 250Kg/h is shown in Fig. 2.8.

A gyratory crusher includes a solid cone set on a revolving shaft and placed within a hollow body, which has conical or vertical sloping sides. Material is crushed when the crushing surfaces approach each other and the crushed products fall through the discharging opening.

Hammer crushers are used either as a one-step primary crusher or as a secondary crusher for products from a primary crusher. They are widely used for crushing hard metal scrap for different hard metal recycling processes. Pivoted hammers are pendulous, mounted on the horizontal axes symmetrically located along the perimeter of a rotor. Crushing takes place by the impact of material pieces with the high speed moving hammers and by contact with breaker plates. A cylindrical grating or screen is placed beneath the rotor. Materials are reduced to a size small enough to pass through the openings of the grating or screen. The size of the product can be regulated by changing the spacing of the grate bars or the opening of the screen.

The feature of the hammer crushers is the appearance of elevated pressure of air in the discharging unit of the crusher and underpressure in the zone around the shaft close to the inside surface of the body side walls. Thus, the hammer crushers also act as high-pressure, forced-draught fans. This may lead to environmental pollution and product losses in fine powder fractions. A design for a hammer crusher (Fig. 2.9) essentially allows a decrease of the elevated pressure of air in the crusher discharging unit [5]. The A-zone beneath the screen is communicated through the hollow ribs and openings in the body side walls with the B-zone around the shaft close to the inside surface of body side walls. As a result, the circulation of suspended matter in the gas between A and B zones is established and the high pressure of air in the discharging unit of crusher is reduced.

Crushers are widely used as a primary stage to produce the particulate product finer than about 50100 mm in size. They are classified as jaw, gyratory and cone crushers based on compression, cutter mill based on shear and hammer crusher based on impact.

A jaw crusher consists essentially of two crushing plates, inclined to each other forming a horizontal opening by their lower borders. Material is crushed between a fixed and a movable plate by reciprocating pressure until the crushed product becomes small enough to pass through the gap between the crushing plates. Jaw crushers find a wide application for brittle materials. For example, they are used for comminution of porous copper cake.

A gyratory crusher includes a solid cone set on a revolving shaft and placed within a hollow body, which has conical or vertical sloping sides. Material is crushed when the crushing surfaces approach each other and the crushed products fall through the discharging opening.

Hammer crushers are used either as a one-step primary crusher or as a secondary crusher for products from a primary crusher. They are widely used for crushing of hard metal scrap for different hard metal recycling processes.

Pivoted hammers are pendulous, mounted on the horizontal axes symmetrically located along the perimeter of a rotor and crushing takes place by the impact of material pieces with the high speed moving hammers and by contact with breaker plates. A cylindrical grating or screen is placed beneath the rotor. Materials are reduced to a size small enough pass through the openings of the grating or screen. The size of product can be regulated by changing the spacing of the grate bars or the opening of the screen.

The feature of the hammer crushers is the appearance of elevated pressure of air in the discharging unit of the crusher and underpressure in the zone around of the shaft close to the inside surface of the body side walls. Thus, the hammer crushers also act as high-pressure forced-draught fans. This may lead to environmental pollution and product losses in fine powder fractions.

A design for a hammer crusher (Figure 2.6) allows essentially a decrease of the elevated pressure of air in the crusher discharging unit [5]. The A-zone beneath the screen is communicated through the hollow ribs and openings in the body side walls with the B-zone around the shaft close to the inside surface of body side walls. As a result, circulation of suspended matter in the gas between A- and B-zones is established and high pressure of air in the discharging unit of crusher is reduced.

For a particular operation where the ore size is known, it is necessary to estimate the diameter of rolls required for a specific degree of size reduction. To estimate the roll diameter, it is convenient to assume that the particle to be crushed is spherical and roll surfaces are smooth. Figure6.2 shows a spherical particle about to enter the crushing zone of a roll crusher and is about to be nipped. For rolls that have equal radius and length, tangents drawn at the point of contact of the particle and the two rolls meet to form the nip angle (2). From simple geometry it can be seen that for a particle of size d, nipped between two rolls of radius R:

Equation (6.2) indicates that to estimate the radius R of the roll, the nip angle is required. The nip angle on its part will depend on the coefficient of friction, , between the roll surface and the particle surface. To estimate the coefficient of friction, consider a compressive force, F, exerted by the rolls on the particle just prior to crushing, operating normal to the roll surface, at the point of contact, and the frictional force between the roll and particle acting along a tangent to the roll surface at the point of contact. The frictional force is a function of the compressive force F and is given by the expression, F. If we consider the vertical components of these forces, and neglect the force due to gravity, then it can be seen that at the point of contact (Figure6.2) for the particle to be just nipped by the rolls, the equilibrium conditions apply where

As the friction coefficient is roughly between 0.20 and 0.30, the nip angle has a value of about 1117. However, when the rolls are in motion the friction characteristics between the ore particle will depend on the speed of the rolls. According to Wills [6], the speed is related to the kinetic coefficient of friction of the revolving rolls, K, by the relation

Equation (6.4) shows that the K values decrease slightly with increasing speed. For speed changes between 150 and 200rpm and ranging from 0.2 to 0.3, the value of K changes between 0.037 and 0.056. Equation (6.2) can be used to select the size of roll crushers for specific requirements. For nip angles between 11 and 17, Figure6.3 indicates the roll sizes calculated for different maximum feed sizes for a set of 12.5mm.

The maximum particle size of a limestone sample received from a cone crusher was 2.5cm. It was required to further crush it down to 0.5cm in a roll crusher with smooth rolls. The friction coefficient between steel and particles was 0.25, if the rolls were set at 6.3mm and both revolved to crush, estimate the diameter of the rolls.

It is generally observed that rolls can accept particles sizes larger than the calculated diameters and larger nip angles when the rate of entry of feed in crushing zone is comparable with the speed of rotation of the rolls.

Jaw crushers are mainly used as primary crushers to produce material that can be transported by belt conveyors to the next crushing stages. The crushing process takes place between a fixed jaw and a moving jaw. The moving jaw dies are mounted on a pitman that has a reciprocating motion. The jaw dies must be replaced regularly due to wear. Figure 8.1 shows two basic types of jaw crushers: single toggle and double toggle. In the single toggle jaw crusher, an eccentric shaft is installed on the top of the crusher. Shaft rotation causes, along with the toggle plate, a compressive action of the moving jaw. A double toggle crusher has, basically, two shafts and two toggle plates. The first shaft is a pivoting shaft on the top of the crusher, while the other is an eccentric shaft that drives both toggle plates. The moving jaw has a pure reciprocating motion toward the fixed jaw. The crushing force is doubled compared to single toggle crushers and it can crush very hard ores. The jaw crusher is reliable and robust and therefore quite popular in primary crushing plants. The capacity of jaw crushers is limited, so they are typically used for small or medium projects up to approximately 1600t/h. Vibrating screens are often placed ahead of the jaw crushers to remove undersize material, or scalp the feed, and thereby increase the capacity of the primary crushing operation.

Both cone and gyratory crushers, as shown in Figure 8.2, have an oscillating shaft. The material is crushed in a crushing cavity, between an external fixed element (bowl liner) and an internal moving element (mantle) mounted on the oscillating shaft assembly. An eccentric shaft rotated by a gear and pinion produces the oscillating movement of the main shaft. The eccentricity causes the cone head to oscillate between the open side setting (o.s.s.) and closed side setting (c.s.s.). In addition to c.s.s., eccentricity is one of the major factors that determine the capacity of gyratory and cone crushers. The fragmentation of the material results from the continuous compression that takes place between the mantle and bowl liners. An additional crushing effect occurs between the compressed particles, resulting in less wear of the liners. This is also called interparticle crushing. The gyratory crushers are equipped with a hydraulic setting adjustment system, which adjusts c.s.s. and thus affects product size distribution. Depending on cone type, the c.s.s. setting can be adjusted in two ways. The first way is by rotating the bowl against the threads so that the vertical position of the outer wear part (concave) is changed. One advantage of this adjustment type is that the liners wear more evenly. Another principle of setting adjustment is by lifting/lowering the main shaft. An advantage of this is that adjustment can be done continuously under load. To optimize operating costs and improve the product shape, as a rule of thumb, it is recommended that cones always be choke-fed, meaning that the cavity should be as full of rock material as possible. This can be easily achieved by using a stockpile or a silo to regulate the inevitable fluctuation of feed material flow. Level monitoring devices that detect the maximum and minimum levels of the material are used to start and stop the feed of material to the crusher as needed.

Primary gyratory crushers are used in the primary crushing stage. Compared to the cone type crusher, a gyratory crusher has a crushing chamber designed to accept feed material of a relatively large size in relation to the mantle diameter. The primary gyratory crusher offers high capacity thanks to its generously dimensioned circular discharge opening (which provides a much larger area than that of the jaw crusher) and the continuous operation principle (while the reciprocating motion of the jaw crusher produces a batch crushing action). The gyratory crusher has capacities starting from 1200 to above 5000t/h. To have a feed opening corresponding to that of a jaw crusher, the primary gyratory crusher must be much taller and heavier. Therefore, primary gyratories require quite a massive foundation.

The cone crusher is a modified gyratory crusher. The essential difference is that the shorter spindle of the cone crusher is not suspended, as in the gyratory, but is supported in a curved, universal bearing below the gyratory head or cone (Figure 8.2). Power is transmitted from the source to the countershaft to a V-belt or direct drive. The countershaft has a bevel pinion pressed and keyed to it and drives the gear on the eccentric assembly. The eccentric assembly has a tapered, offset bore and provides the means whereby the head and main shaft follow an eccentric path during each cycle of rotation. Cone crushers are used for intermediate and fine crushing after primary crushing. The key factor for the performance of a cone type secondary crusher is the profile of the crushing chamber or cavity. Therefore, there is normally a range of standard cavities available for each crusher, to allow selection of the appropriate cavity for the feed material in question.

The main task of renovation construction waste handling is the separation of lightweight impurities and construction waste. The rolling crusher with opposite rollers is capable of crushing the brittle debris and compressing the lightweight materials by the low-speed and high-pressure extrusion of the two opposite rollers. As the gap between the opposite rollers, rotation speed, and pressure are all adjustable, materials of different scales in renovation construction waste can be handled.

The concrete C&D waste recycling process of impact crusher+cone crusher+hoop-roller grinder is also capable of handling brick waste. In general, the secondary crushing using the cone crusher in this process with an enclosed crusher is a process of multicrushing, and the water content of waste will become an important affecting factor. The wet waste will be adhered on the wall of the grinding chamber, and the crushing efficiency and waste discharging will be affected. When the climate is humid, only coarse impact crushing is performed and in this case the crushed materials are used for roadbase materials. Otherwise, three consecutive crushings are performed and the recycled coarse aggregate, fine aggregate, and powder materials are collected, respectively.

The brick and concrete C&D waste recycling process of impact crusher+rolling crusher+hoop-roller grinder is also capable of handling the concrete waste. In this case, the water content of waste will not be an important affecting factor. This process is suitable in the regions with wet climates.

The renovation C&D waste recycling process of rolling crusher (coarse/primary crushing)+rolling crusher (intermediate/secondary crushing)+rolling crusher (fine/tertiary crushing) is also capable of handling the two kinds of waste discussed earlier. The particle size of debris is crushed less than 20mm and the lightweight materials are compressed, and they are separated using the drum sieve. The energy consumption is low in this process; however, the shape of products is not good (usually flat and with cracks). There is no problem in roadbase material and raw materials of prefabricated product production. But molders (the rotation of rotors in crusher is used to polish the edge and corner) should be used for premixed concrete and mortar production.

flsmidth to provide gyratory crushers and apron feeders to copper and gold mine in chile

flsmidth to provide gyratory crushers and apron feeders to copper and gold mine in chile

The order, which comes after two years of close, preparatory work with the customer, comprises two 1400x2100 TSU Gyratory Crushers and three Apron Feeders of varying sizes. The mine, located at almost 2,400 meters above sea level and around 1,500 kilometres north of Santiago, is currently undergoing an important expansion and transformation process.

This order is fantastic news for FLSmidth as it demonstrates our strength and competitiveness in the crushing and comminution area. It is a great vote of confident from an important and large mine operator to choose FLSmidth gyratory crushers for their first such purchase in 20 years. Ultimately, this order comes as a result of our close work with the customer and our effort to understand their specific conditions. This meant we could provide the right productivity- and sustainability-enhancing solutions and service, comments Claudio Garcia Bernal, FLSmidth Regional President for South America.

The FLSmidth equipment was chosen by the customer as it is specifically designed for high performance and cost-effective operation due to low servicing and maintenance needs. Each crushers capacity is 2,500 mtph, while the feeders operate at 2,500 t/h (speed: 0,25 m/s).

FLSmidths TSU Gyratory Crusher is specifically designed for extreme applications, where extra motor power and heavier sections are needed and where reliability and minimised maintenance are key factors. The TSU also provides higher throughput capacities.

The TSU Gyratory Crusher is unique among gyratory crushers due to its revolutionary design Top Service (TS) design, which allows for easy access and removal of the eccentric assembly, bushings and hydraulic piston through the top of the crusher. This feature greatly simplifies service functions and provides safety benefits, not found on traditional bottom service machines. As a result, the TSU reduces overall costs and helps to make this a more sustainable and available crushing option.

FLSmidth provides sustainable productivity to the global mining and cement industries. We deliver market-leading engineering, equipment and service solutions that enable our customers to improve performance, drive down costs and reduce environmental impact. Our operations span the globe and we are close to 10,200 employees, present in more than 60 countries. In 2020, FLSmidth generated revenue of DKK 16.4 billion. MissionZero is our sustainability ambition towards zero emissions in mining and cement by 2030.

rock crushing rule of thumb

rock crushing rule of thumb

Gyratory crusher: feed diameter 0.75 to 1.5m; reduction ratio 5:1 to 10:1, usually 8:1; capacity 140 to 1000 kg/s; Mohs hardness <9. More suitable for slabby feeds than jaw crusher. [reduction by compression].

gyratory crusher (ts) for harsh environments

gyratory crusher (ts) for harsh environments

Crushing tonnes upon tonnes of solid rock takes its toll on your equipment. That is why, throughout the worlds mines and rock quarries, decision makers are choosing FLSmidth Gyratory Crushers. Our Gyratory Crusher (TS) is built upon a centurys worth of mining and engineering experience. When you want a crusher that can withstand the harshest requirements, the Gyratory Crusher (TS) has you covered.

The Gyratory Crusher TS is a high quality, modern design, durable gyratory crusher that was engineered from the ground up with an unwavering focus on performance, safety, maintenance and functionality, for the utmost reliability and efficiency in your projects.

The Gyratory Crusher TS is distinguished from other gyratory crushers by its revolutionary design which allows you to easily and safely perform major service and maintenance functions. It is designed so that you can easily access and remove the eccentric assembly, bushings and hydraulic piston through the top of the crusher, hence the name Top Service. The Top Service feature greatly simplifies service functions and provides safety benefits, not found on traditional bottom service machines. As a result it reduces your overall costs and helps to make this a more sustainable and available option for you.

Trust the solution that is built using the most advanced analysis techniques, for a crusher that is structurally sound from the inside out. And because your business is unique, the Gyratory Crusher (TS) is not only durable, but also flexible enough to meet your varying needs and requirements in a dynamic way.

The Gyratory Crusher TS design allows for a more cost effective and flexible layout of your crushing station. It features multiple counterbalancing options for mobile and semi-mobile applications, which reduce out-of-balance forces. The end result is you saving money through the use of fewer building materials.

FLSmidth provides sustainable productivity to the global mining and cement industries. We deliver market-leading engineering, equipment and service solutions that enable our customers to improve performance, drive down costs and reduce environmental impact. Our operations span the globe and we are close to 10,200 employees, present in more than 60 countries. In 2020, FLSmidth generated revenue of DKK 16.4 billion. MissionZero is our sustainability ambition towards zero emissions in mining and cement by 2030.

flsmidth to provide gyratory crushers and apron feeders to copper and gold mine in chile - international mining

flsmidth to provide gyratory crushers and apron feeders to copper and gold mine in chile - international mining

FLSmidth has been chosen to provide two gyratory crushers and three apron feeders to a copper and gold mine in the Antofagasta Region of northern Chile. The order, which comes after two years of close, preparatory work with the customer, comprises two 1400 x 2100 TSU Gyratory Crushers and three Apron Feeders of varying sizes. The mine, located at almost 2,400 m above sea level and around 1,500 km north of Santiago, is currently undergoing an important expansion and transformation process. The order was booked in Q1 2021.

This order is fantastic news for FLSmidth as it demonstrates our strength and competitiveness in the crushing and comminution area. It is a great vote of confident from an important and large mine operator to choose FLSmidth gyratory crushers for their first such purchase in 20 years. Ultimately, this order comes as a result of our close work with the customer and our effort to understand their specific conditions. This meant we could provide the right productivity- and sustainability-enhancing solutions and service, comments Claudio Garcia Bernal, FLSmidth Regional President for South America.

The FLSmidth equipment was chosen by the customer as it is specifically designed for high performance and cost-effective operation due to low servicing and maintenance needs. Each crushers capacity is 2,500 t/h, while the feeders operate at 2,500 t/h (speed: 0.25 m/s).

FLSmidth says its TSU Gyratory Crusher is specifically designed for extreme applications, where extra motor power and heavier sections are needed and where reliability and minimised maintenance are key factors. The TSU also provides higher throughput capacities. The TSU Gyratory Crusher is unique among gyratory crushers due to its revolutionary design Top Service (TS) design, which allows for easy access and removal of the eccentric assembly, bushings and hydraulic piston through the top of the crusher. This feature greatly simplifies service functions and provides safety benefits, not found on traditional bottom service machines. As a result, the TSU reduces overall costs and helps to make this a more sustainable and available crushing option.

new secondary crushers concentrate on higher productivity | e & mj

new secondary crushers concentrate on higher productivity | e & mj

The knowledge base associated with secondary/tertiary crushing of hard rock minerals has grown exponentially over the past century or so, starting with the realizationreported by an industry expert in the July 1916 issue of E&MJthat probably the most important development in ore crushing in recent years is the growth of the idea that no machine in existence is capable of crushing ore efficiently from large pieces to the fine meshes necessary in preparing most ores for treatment

Today, fine/pebble crushing is an integral part of most large hard rock mills, and crusher suppliers keep expanding the available options for outfitting secondary crusher plants to suit the needs of specific mine-site characteristics. The prevailing features of these new models emphasize improved capacity, control, energy consumption and ease of maintenance.

Both Metso and Sandvik have, in the past few months, introduced new models of cone or gyratory crushers that can accommodate customer demands for these capabilities. Other manufacturers, such as FLSmidth, Telsmith and ThyssenKrupp Frdertechnik also offer relatively new and highly capable cone crusher models as well with their Raptor, T Series and Kubria lines, respectively.

SANDVIK EXPANDS ITS MID-RANGESandvik Mining added to its CH800 series of mining cone crushers by launching two models in the mid-range segment. The new CH860 is designed for high-capacity secondary crushing, while the CH865 is intended for high-reduction tertiary and pebble applications; both feature higher crushing forces relative to mantle diameter and a 500-kW motor. According to the company, both new crushers combine a range of advanced automation features for a more secure and productive process.

We scaled down our larger Sandvik CH890 and Sandvik CH895 mining cone crushers to create two mid-range models, said Andreas Christoffersson, product line manager for cone crushers at Sandvik Mining. Depending on the application, [the] CH860 and Sandvik CH865 outperform competing equipment in the mid-range segment by as much as 30% and deliver a twofold increase in performance range.

Intelligent systems in the CH860 and CH865 are claimed to enable real-time performance optimization, while innovative design solutions reduce dynamic loads and minimize engineering and installation work. The crushers feature fewer moving parts than competing models, according to Christoffersson. Bolted, not welded, liners on the top and bottom shell enable safer, easier maintenance.

Both new crushers also feature the companys ASRi (Automatic Setting Regulation control system) and Hydroset to ensure automatic operation at peak performance around the clock. ASRi constantly monitors pressure, power draw and mainshaft position and automatically adjusts the setting during full load.

The Hydroset main shaft support system provides protection from overloads by permitting tramp iron and other uncrushable items to pass through the crusher before automatically returning to the original setting. The system automatically compensates for crushing chamber wear to provide consistent product size.

Hydroset enables us to incorporate our unique PLC-controlled electric dump valve for tramp iron protection, which significantly reduces pressure peaks and mechanical stress on the crusher, greatly improving reliability, Christoffersson explained.

Mines are often looking for increased productivity without necessarily expanding their plant, Christoffersson said. [The] CH860 and Sandvik CH865 are easy to install as replacements to achieve this. In the test site, we replaced a similar sized crusher, on the same foundation, to greatly increase final product and significantly extend crushing chamber liner life. The electric dump valve repeatedly proved its tramp iron protection value, reducing costly unplanned breakdowns.

METSOS LARGEST NORDBERG GYRATORYMetso expanded its range of high-capacity crushers with the introduction of the Nordberg GP7, its largest Nordberg GP secondary gyratory crusher to date. The 58-ton unit features a combination of feed opening, cavity design and capacity that, according to Metso, ensures high crushing performance with even the hardest feed and helps keep operational costs low. In addition, said Metso, the crusher is safe to operate and simple to maintain.

The Nordberg GP7 can be fed with a large primary crusher such as the Nordberg C200 jaw crusher or Nordberg Superior primary gyratory crusher, and followed by a Nordberg HP6 cone crusher for tertiary crushing. The GP7 has the same footprint as the Symons 7-ft and similar crushers, which makes replacement of an existing crusher easy to accomplish.

The crusher features a feed opening of 450 mm (18 in.), which remains constant throughout the lifetime of the linersoffering one of the most significant benefits of the new crusher. A constant feed opening ensures steady performance and stable end-product quality, which translate into predictable revenue and process throughput. Process control is based on advanced Metso IC automation that provides easy, safe and trouble-free operation.

The GP7 offers seven stroke options to ensure adaptability for any application. A steep cavity combined with an easily changeable stroke provides high performance at power ratings up to 550 kW. In fact, said Metso, the Nordberg GP7 has the highest power rating in its size class.

Meanwhile, two Metso MP2500s, billed as the worlds largest cone crusher, are currently being installed at First Quantum Minerals Ltd.s Sentinel copper mine in Zambia. According to Metso, depending on the ore characteristics and SAG efficiency, the MP2500s could provide a throughput range of 3,0004,500 metric tons per hour (mt/h). (See E&MJ, December 2014, p. 102).

FLSMIDTHS XL2000 WIDENS; FLOWSHEET OPTIONSRecognizing the industrys steady trend toward larger equipment size, capacity and tonnage, FLSmidth introduced its Raptor XL2000 cone crusher to meet these new challenges. Although its not new, having been introduced several years ago, the XL2000 remains the flagship model in the Raptor cone crusher line, topping the XL300, XL400, XL500, XL600, XL900, XL1100 and the newer XL1300.

The XL2000 cone crusher is intended for secondary or tertiary applications and does not replace the need for a primary gyratory or jaw crusher. However, the XL2000 can replace a SAG mill, according to the company, thereby reducing overall costs while still maintaining circuit capacity and producing a product crushed to specific requirements.

Due to the large size and weight of the main frame required for the XL2000, FLSmidth engineers involved in its design borrowed concepts from the companys primary gyratory two-piece frame with its taper-interlock connection. This two-piece frame allows flexibility in sourcing, transport and ease of handling on site.

The 2,000-hp XL2000 has high crushing force (4,220,000 lb/1,914,000 kg) with advanced head-motion dynamics. To safely apply this force, FLSmidth engineers focused on ensuring the structural integrity of all major components. Component mass was critical, and the company said the machines design reflects what is expected of a robust 2,000-hp cone crusher that must reliably and durably handle the tough material characteristics and applications for which it was designed.

FLSmidth believes the XL2000 creates new opportunities for miners to link cone crushers directly to the primary crushing station. Instead of settling for a 180- to 200-mm product from a 6,000-t/h primary gyratory crusher, the XL2000 could supplement that primary gyratory to produce up to 10,000 t/h and a 125-mm product that is ready for more efficient crushing in the next stage, according to the company.

Copper Mountain Mining installed an XL2000 Raptor at its flagship mine in southern British Columbia last year, as part of a $40 million program to increase its secondary crushing capacity and improve mill efficiency. The new Copper Mountain machine is regarded as the largest cone crusher installed in western Canada and has the ability to crush 6-in. rock from the primary crusher down to minus 2 in., which will allow the mill to operate consistently at or above design capacity rates of 35,000 t/d.

TELSMITHS MID-SIZED NEWCOMERTelsmith rolled out its T400 cone crusher in 2014, filling another slot in the T Series line that includes the high-capacity, mine-duty T900 and the smaller T300. The T400 feature set includes a 1,321-mm diameter head, a 1,397-mm receiving hopper, replaceable mainframe liners, epoxy-secured manganese steel crushing members and more.

The T400 is equipped with Telsmiths innovative hybrid bearings that have a washer and ramp design, which replaces the conventional use of a socket, socket liner and head ballall of which typically involve time-consuming removal when servicing the machine. Telsmith noted that, unlike roller bearing machines, these large hybrid bearings have both static and dynamic lift, providing substantially better lift overall to efficiently handle the crushing forces.

The T Series line offers nominal output capacities ranging from 110 to 2,100 mt/h with power ratings from 220 kW (300 hp) in the smallest size to 660 kW (900 hp) at the high end of the line. Design features include large clearing circuits, a patent-pending, anti-spin feature that prevents head spin to help extend manganese service life. The use of a single bowl for all liners helps reduce downtime and inventory costs.

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