SIEBTECHNIK TEMA is part of a globally operating group of companies with around 3,500 employees in more than 50 companies with a clear focus on the processing of mineral bulk solids as well as solid-liquid separation in the chemical and food industries. A company policy of controlled, self-financed growth, which has been consistently implemented in almost 100 years of company history, not only ensures a healthy economic base and an exceptionally good strategic position, but also an impressive worldwide presence. We see the challenges of the globalized world market as an opportunity for further positive corporate development.
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.
Xinhai mineral processing equipment mainly include: grinding equipment, flotation equipment, dewatering equipment, magnetic separation equipment, and so on. Some of the equipment is Xinhai independent research and development, and has been awarded national patent. View details
Gold CIP Production Line adsorbs gold from cyaniding pulp by active carbon including 7 steps: leaching pulp preparation, cyaniding leaching, carbon adsorption, gold loaded carbon desorption, pregnant solution electrodeposit, carbon acid regeneration, leaching pulp. View details
Conducted design and research and supplied equipment for about2000mines, completed500 mine EPC+M+O projects in 90countries and regions, we are dedicated to providing you with the one-stop and customized mine solutions!
Thickener underflow was pumped by slurry pump to the trash screen; gold-bearing carbon was gained through leaching, absorption and carbon extraction; gold slime was produced after high-temperature high-voltage desorption electrolysis system; crude gold ingots were produced after smelting.
For civil engineering, steel structure was adopted for ore bins, platforms and foundations on the ground as far as possible. Original dump leaching tank was utilized. Despite of cultural differences and challenges in civil construction and equipment installation, Xinhai maintained close communication with the client, earnestly answered the clients questions and modified the drawings according to particular field conditions. For equipment installation and commissioning, experienced staff were sent to provide technical guidance for the client, which significantly shortened the construction duration. As a result, the projects economic benefits exceeded the expectations and were well received by the client.
Before sale Be a good customers adviser and assistant, let the users every investment get rich returns. (1) selection of equipment model. (2) design and manufacture products according to customers special requirements. (3) training technical personnel for customers. Sale Respect customers; Give customers rest assured, a relaxed, a surprise; Committed to improving the overall value of customers. (1) product acceptance. (2) assist the client to draw up the construction plan. After-sale (1) assign special after-sales service personnel to guide the installation and debugging of customers on-site. (2) equipment installation and debugging. (3) on-site training of operators.
JXSC has been focusing on mining equipment manufacturing since 1985. Products: rock crushers, gravity separator, electrostatic separator, flotation machine, washing equipment, ore feeder, screen & sieve, etc. Application: metallurgical, mineral processing, sand making, aggregate processing, etc. Contact us for quotation
Notes: 1. Services (installation, test run, training) : the supplier can provide basic drawings and schematic drawings of equipment installation. The domestic technicians will be provided for free to guide installation and debugging, and the buyer will provide technicians with room and board. The buyer shall prepare necessary auxiliary materials for installation. 2. Quality guarantee: the equipment is guaranteed for one year. In the warranty period, due to the quality of the product manufacturing, manufacturers free warranty (except wearing parts).
Case study: 50TPH Silica Sand Processing & Washing Plant in Indonesia, how processing plant configuration and what equipments were used? Read more You may interest in the silica sand property and processing methods.
Project: extraction of scrubbed silica sand (use for glass, cement industry) Material: silica sand Capacity: 50TPH Country: Indonesia Mineral condition description: raw silica sand contains slime and barren rock, which is up to 25-30 CM in diameter. Customers requirements: wash the mud off and sieve the barren rock out.
JXSC has been focusing on mining equipment manufacturing since 1985. Products: rock crushers, gravity separator, electrostatic separator, flotation machine, washing equipment, ore feeder, screen & sieve, etc. Application: metallurgical, mineral processing, sand making, aggregate processing, etc. Contact us for quotation
Separate crushed materials and gravel into different sizes through large screens or industrial screens. As part of the crushing operation, coarse screens called grizzly bears or oxen are used to separate too large or too small materials from raw materials.Screens have static, horizontal and cylindrical screens, but today, most factories use inclined vibrating screens. The screening equipment determines the clear and reliable material separation, which provides the basis for the subsequent mineral processing.
Main parts of high frequency vibrating screen are mainframe, screen, electric vibrators, electric motor, rub spring and coupler.The screening decks are capable of single to triple decks, greatly improve the screening efficiency and capacity. Besides, providing a thin and loose bed of particles, which as well as do a good effect on the screen.Sieving is one of the oldest and most widely used physical size separation methods and is widely used in industry. In the continuous screening process, high frequency and low amplitude features lead to the vertical elliptical movement, the particles that fall from the feed hopper and reach the surface of the screen are sorted under the action of gravity. Oversized particles rebound along the screen, and most undersized particles pass through the holes.
High frequency vibrating screen is the most important screening machine mainly used in the beneficiation industry. They are used to separate materials containing solids and crushed ores with a particle size of less than 200 m. Wetting or drying materials can be sieved.Unlike the ordinary vibrating screen, the frequency of high-frequency screening is controlled by an electromagnetic vibrator installed above the surface of the screen and directly connected to the surface of the screen, and the vibration frequency is adjustable.High-frequency vibrating screens are usually operated at an angle of inclination, traditionally varying between 0 and 25 degrees, up to 45 degrees. In addition, it should operate at a low stroke with a frequency range of 1500-7200 RPM. Before using a high-frequency screen, it is usually necessary to pretreat the feed, because the holes in the screen are easily blocked.
The limitation of the high frequency vibrating screen is that the fine screen is very fragile and easily blocked. As time goes by, the separation efficiency will decrease and the screen needs to be replaced.
Circular vibrating screenThe multi-layer vibrating screen is specially designed for screening stones in quarries. It can also be used to classify products in coal preparation, mineral processing, building material production, power and chemical industries.The main advantages of the circular vibrating screen are as follows.(1) By adjusting the excitation force, the flow rate can be changed easily and steadily.(2) The circular vibrating screen has stable vibration, reliable operation and long service life.(3) Simple structure and reliable operation. The relatively light weight and small volume make maintenance easier.(4) The closed structure of the screen effectively prevents dust pollution.(5) Low noise intensity and small power consumption are generated during the operation of the vibrating screen.High frequency vibrating screen(1) Light, durable structure. The compact high-power vibration exciter is used as the drive. No belt or other accessories are required. The screen is very light but durable.(2) Adjustable flow rate. The screening capacity can be adjusted with ease because the stroke can be varied by adjusting the unbalanced weight with the most suited number of poles.(3) Screening capacity can be easily adjusted by adjusting the stroke, frequency, etc.(4) Stable performance. The high power of vibration makes screen run stable, even when screening adhesive materials.(5) Accurate screening. According to the specific materials and flow rate, single-layer to triple-layer deck-type groove can be designed according to the screening requirements to achieve accurate and efficient screening.(6) Simple start, stop. Press the controller button to easily control the start or stop of screening.
In the beneficiation line of various ores, the high-frequency sieve plays a vital role. The high-frequency sieve sifts out the coarse particles and sends them back to the crusher for crushing. At the same time, the fine-grained materials are discharged in time to avoid excessive crushing caused by re-grinding.The sieved materials can enter the next stage of beneficiation process. The use of high-frequency sieve can not only meet the requirements of mineral fineness, but also achieve smaller particle size separation, thereby reducing the capacity and overall energy consumption required in the crushing stage. Therefore, the grade of the final product is improved, and a better recovery rate and screening efficiency are provided.
Xinhai devotes to providing Turn-key Solutions for Mineral Processing Plant (EPC+M+O), namely design and research - complete equipment manufacturing and procurement - commissioning and delivery - mine management - mine operation. The essence of EPC+M+O Service is to ensure sound work in every link. The model is suitable for most of the mines in the world.
Focusing on the research and development and innovation of mineral processing equipment, Xinhai has won more than 100 national patents, strives for perfection, strives to complete the combination of equipment and technology, improve productivity, reduce energy consumption, extend equipment stable operation time, and provide cost-effective services.
With Class B design qualifications in the metallurgical industry, rich in ore mining, beneficiation, smelting technology and experience, completed more than 2,000 mine design and research, not only can provide customers with a reasonable process, but also can provide customized equipment configuration.
The precious metal minerals are mainly gold and silver mines. Xinhai Mining has more than 20 years of experience in beneficiation for gold and silver mines, especially gold ore beneficiation technology. Gold craft and placer gold selection craft etc.
With Class B design qualification, it can provide accurate tests for more than 70 kinds of minerals and design a reasonable beneficiation process. In addition, it can also provide customized complete set of mineral processing equipment and auxiliary parts.
Xinhai can provide the all-round and one-stop mineral processing plant service for clients, solving all the mine construction, operation, management problems, devoting to provide modern, high-efficiency.
Through mineral processing experiment, the mineral processing flow is customized. Multiple tests are carried out in every link, and make sure the final processing flow to guarantee the successful mineral processing plant construction.
According to tailing processing technology, Xinhai has tailings reprocessing technology and tailings dry stacking. Tailings dry stacking is the self-launched tailings dewatering technology, which is the effective technology in green mine construction.
More than 2,000 mine design and research, equipment supply projects, more than 500 mining industry chain services (EPC+M+O) projects in more than 90 countries and regions around the world, we are always committed to providing you with one-stop, customized Chemical mine solution!
The vibrating screen dengan gerakan melingkar dirancang khusus untuk penggalian untuk memisahkan bahan batu pecah menjadi berbagai ukuran, dan juga digunakan sebagai mesin perata dalam pembalut batubara, pembalut bijih, bahan konstruksi, industri listrik dan kimia. ia memiliki fitur struktur maju struktur canggih, kekuatan bergetar kuat, kebisingan getaran rendah, perawatan mudah, daya tahan tinggi dan lain-lain.
Circular vibrating screen adalah sistem getaran paksa massa tunggal yang terdiri dari kotak kotak exciter dan bagian bergerak lainnya sebagai massa dan pegas kumparan logam sebagai elemen elastis. Motor digerakkan oleh exciter coupling tipe ban dan blok eksentrik menghasilkan gaya sentrifugal yang kuat dengan putaran kecepatan tinggi, sehingga kotak layar membuat gerakan lingkaran kontinu wajib.
Bahan digerakkan oleh kekuatan seperti itu untuk membuat gerakan lemparan terus-menerus pada kemiringan permukaan layar dengan bahan-bahan dipisahkan ketika muntah dan ditembus ketika jatuh ke bawah, sehingga menyelesaikan siklus perincian lengkap proses klasifikasi.
Vibramech vibrating screens are custom designed for client needs and cover a vast range of sizes and unique process applications. Our screen design makes use of Finite Element Method and Strain Gauge Analysis to prove structural integrity. Our vibrating screens also feature wear protection and commonality of components to minimise spare parts inventories.
Horizontal Screens Horizontal screens are designed for wet or dry applications, ideal for smaller aperture sizing, de-sliming or dense medium recovery. Available in single-, double- and triple-deck configurations.
Dewatering Screens Vibrator motor-driven dewatering screens are designed for dewatering applications. They feature high G-forces with a dual-sloped screening deck for superior water removal.
Inclined Screens Inclined screens, typically installed at a 15 or 19 deck angle, are combined with an optimised drive configuration. They are designed for large aperture screening or heavy-duty scalping applications.
Liwell Screens Liwell screens are for difficult screening applications where sticky material is screened at small aperture sizes without process water. We are the exclusive sub-Saharan African distributor.
Vibramech screens are equipped with vibrator motor, geared exciter or oscillator drives, and are available in single-, double- or triple-deck configuration. The range of screening media includes polyurethane panels, rubber panels, wedge wire panels or woven wire panels. Screen isolation is achieved using rubber buffers, coil springs or Rosta mount isolators, and screens can be supplied with sub-frames if additional isolation is required.
Our flexibility in design provides customers the freedom to optimise their plant infrastructure without the standard screen geometric constraints, and enables screens to be retrofitted to existing infrastructure. Other features include:
Over 500 units of Vibramech vibrating equipment are supplied and commissioned worldwide each year. Complete the enquiry form to see how Vibramech vibrating screens will optimise your screening processes.
Vibramech has vibrating equipment installed throughout Africa and internationally, including Australia, Canada, China, India, USA and South America, Philippines, Russia and United Kingdom. This has resulted in an installed base of over 8000 pieces of Vibramech vibrating mineral processing equipment worldwide.
Vibramech supplies vibrating equipment primarily to the mining and mineral processing industries across the globe and has extensive experience in gold, diamond, coal, iron ore, manganese, platinum, chrome, nickel, uranium, copper, mineral sands and aggregate operations.
Industrial Vibrating Screen Machine, Soil Mechanical Sieve Shaker Mechanical Sieve Shaker This new electro-mechanical shaker features efficient sieving action, heavy duty and simple design. The sieve column is held at the top by a rubber pad with spherical seat and rotates eccentrically at the bottom ensuring uniform shaking of the sample across the whole surface of the sieves. Upon each revolution, a simple mechanical mechanism imparts hits at the base of the sieve column so as to move the sample on the sieve surface for a very efficient sieving action. The front panel includes the mains switch, the emergency stops button and timer. The shaker has to be fixed to the base through the four holes at the base. A noise reduction cabinet is also available for housing the shaker. See accessories. Product Description This machine, the main fuction is dehydration, desludge, de-intermediation, can be used for sand washing in sand and gravel plant, coal slurry recovery in coal preparation plant, dry discharge of tailings in mineral processing plant, etc., so it is also called sand stone dewatering sieve and mining dewatering sieve., slime dewatering screen, tailings dwwatering screen, etc. The Vibrating dewatering screen adopts double vibration motor or flange type vibration exciter (self-synchronous rotation by two ordinary motors to rotate in the opposite direction), so that the sieve body can be periodically reciprocated in a straight line direction to achieve the purpose of grading dehydration. Mechanical Sieve Shaker Capacity Sieve Capacity ranges from six 12-inch full-height sieves to twenty one 8-Inch half-height sieves. Sieves are locked in for testing quickly and securely with our exclusive EZ-Clamp system. The Mechanical Sieve Shaker uses an easy to operate clamping system with integral sieve cover slides freely up and down the clamp rods with the push of a button. Once in position, a quick twist secures the sieve stack. When the test is complete, this sieve shaker will raise just enough to remove the stack, and the clamps stay in place, ready for the next test without readjustment. Mechanical Sieve Shaker Features Test times are controlled with a reliable mechanical-electrical timer with adjustable stop for repeatable times and a "hold" feature for continuous operation. This mechanical sieve shaker also includes a powerful 1/4hp motor and all mechanical and electrical parts are enclosed in the rugged painted steel case with rubber feet. Mechanical Sieve Shaker Main Features 1. Double effect electromechanical sieving 2. High sieve capacity 3. For sieves up to 450 mm dia. 4. Ergonomic and fast clamping system 5. Timer function included 6. Noise reduction cabinet available. See accessories. 7. Wet sieving attachments available. See accessories.
Mechanical Sieve Shaker This new electro-mechanical shaker features efficient sieving action, heavy duty and simple design. The sieve column is held at the top by a rubber pad with spherical seat and rotates eccentrically at the bottom ensuring uniform shaking of the sample across the whole surface of the sieves. Upon each revolution, a simple mechanical mechanism imparts hits at the base of the sieve column so as to move the sample on the sieve surface for a very efficient sieving action. The front panel includes the mains switch, the emergency stops button and timer. The shaker has to be fixed to the base through the four holes at the base. A noise reduction cabinet is also available for housing the shaker. See accessories.
Product Description This machine, the main fuction is dehydration, desludge, de-intermediation, can be used for sand washing in sand and gravel plant, coal slurry recovery in coal preparation plant, dry discharge of tailings in mineral processing plant, etc., so it is also called sand stone dewatering sieve and mining dewatering sieve., slime dewatering screen, tailings dwwatering screen, etc.
The Vibrating dewatering screen adopts double vibration motor or flange type vibration exciter (self-synchronous rotation by two ordinary motors to rotate in the opposite direction), so that the sieve body can be periodically reciprocated in a straight line direction to achieve the purpose of grading dehydration.
Mechanical Sieve Shaker Capacity Sieve Capacity ranges from six 12-inch full-height sieves to twenty one 8-Inch half-height sieves. Sieves are locked in for testing quickly and securely with our exclusive EZ-Clamp system. The Mechanical Sieve Shaker uses an easy to operate clamping system with integral sieve cover slides freely up and down the clamp rods with the push of a button. Once in position, a quick twist secures the sieve stack. When the test is complete, this sieve shaker will raise just enough to remove the stack, and the clamps stay in place, ready for the next test without readjustment.
Mechanical Sieve Shaker Features Test times are controlled with a reliable mechanical-electrical timer with adjustable stop for repeatable times and a "hold" feature for continuous operation. This mechanical sieve shaker also includes a powerful 1/4hp motor and all mechanical and electrical parts are enclosed in the rugged painted steel case with rubber feet.
Mechanical Sieve Shaker Main Features 1. Double effect electromechanical sieving 2. High sieve capacity 3. For sieves up to 450 mm dia. 4. Ergonomic and fast clamping system 5. Timer function included 6. Noise reduction cabinet available. See accessories. 7. Wet sieving attachments available. See accessories.
Triple/S Dynamics has been manufacturing equipment for the minerals/mining industries since its founding in 1888. The harsh environments of this industry require heavy-duty construction that promotes reliability.
In the last twenty years, over 5,000 feet of Slipstick Industrial Conveyor has been moving hundreds of thousands of pounds of silica, quicklime, limestone, nepheline syenite, coal, pebble lime, and many other products that fall into this category.
Cement clinker is produced by heating to high temperature a mixture of substances such as limestone and shale. When cement clinker is ground with a specified amount of gypsum, it will produce Portland cement or when ground with specified amounts of gypsum and other materials it will produce blended cements.
Slipstick Conveyors have found their way into this process replacing buckets or belts. The Slipstick can handle this very hard and abrasive duty, highlighting other qualities of this conveyor including low abrasion, dust tight, low maintenance, and the ability to meter the feed downstream.
Potash is any of various mined and manufactured salts that contain potassium in water-soluble form. The name derives from pot ash, which refers to plant ashes soaked in water in a pot, the primary means of manufacturing the product before the industrial era.
Triple/S Dynamics equipment has been screening and conveying salt, in various forms, for over thirty years. From conveying table salt to flakes or screening to size salt pellets, the Slipstick Conveyor and the Texas Shaker Vibrating Screen have performed exceptionally well for decades.
The Slipstick Industrial Conveyor is the best choice for moving all types of sand, rock, or silica products. One processor came to us because the dust generated from a cutting process was causing bearings on the existing belt conveyor to fail very quickly.
Today, the S-25 Sutton Gravity Separator is separating the light from heavy (expanded from the unexpanded) vermiculite, in a range of separation across the face of the deck. In another application, the Sutton T-15 Stoner makes a two-way stream of heavy and light perlite product.
Henan Yuanren Mining Equipment Co.,Ltd was established in early 1994, is a professional engaged in mining equipment, mineral processing equipment, drying equipment design, fine screening research and development and production of enterprises. After more than 20 years of growth, along with the level of business and production capacity continues to rise, in early 2008 began to increase the international trade department. So far the product sales surface covering more than and 30 countries and regions at home and abroad.
Large vibrating screens represent a unique challenge for Manufacturers, Plant Designers, and Plant Operators. The inherent mode of operation for vibrating screens is self-destructive. More often than Manufacturers admit, Designers plan for, or Operators staff for, a vibrating screen succeeds and self-destructs. This is a problem. It can magnify with larger vibrating screens.
Vibrating screen structures are subjected to nearly 250 million fatigue cycles in an operating year. The design and construction of these structures are critical in achieving reliable screen performance. Regardless of screen size, the maxims for design continue to be:
A screen design meeting these criteria yields the lowest cost per ton performance. Large screen technology is evolving more scientifically than did the development of small screen technology. As vibrating screen designs increase beyond six foot widths, reliable designs result from sophisticated engineering methods and manufacturing techniques. In addition, large screen technology amplifies the direct relationship of production cost and reliability.
Static Stresses: At rest, motionless, a vibrating screen structure is subjected to the force of gravity, at a minimum. A vibrating screen must first support its own weight. Other motionless stresses are present in the structure as a result of cutting, bending, welding, burning, drilling, assembly, tolerancing, and manufacturing variances. Quite simply, these stresses exist whether or not the screen is operating.
The second step in FEA can be considered the construction of structural loads. These include the imposition of static, dynamic, material, and fatigue conditions on the mathematical model, which approximates the load conditions. An example would be to describe a structural misalignment and the forces input co bolt up this structure through the misalignment.
Reliable vibrating screen designs are dependent upon the proper marriage of a firms manufacturing capabilities and the requirements of the design. It is not reasonable to expect that closely toleranced airframes will be successfully produced in a metal-bending job shop. As design safety factors narrow on larger screens, manufacturing techniques evolve which minimize production variables. Design tolerancing is necessarily compatible with manufacturing accuracy.
Residual metal working stress is the left-over stress in metal when melted or formed into a shape. It is a result of a materials resistance to change shape. Stress concentration sites are more commonly termed notches or stress risers. These areas are not stresses, but sharp geometric transitions or reversals in a structure. Stress loads focus their effect on a structure at these sites. Experience has proven that the methods and procedures of structural assembly can result in preloading screen bodies with excessive static stresses. The scope of this discussion is limited to the discussion of welding, forming, and bolting as they relate to conditions described above.
The side plate of a vibrating screen literally bristles with fasteners. Multi-shift production facilities, as well as maintenance crews, quickly realize the merits of this system. Unlike conventional threaded fasteners, swaged bolts exhibit a distinctly different physical appearance when installed versus loosely installed. The guess-work and wasted efforts to repeatedly insure all bolts are properly torqued are eliminated. A second-shift assembler need not consult with his first-shift counter-part regarding loose or torqued bolts . Sound maintenance practice precludes the reuse of major structural fasteners. A huck-type fastener is destroyed during removal. Normal threaded fasteners depend on proper installation torques to achieve the optimum clamping force. Registered torque wrench values may not be indicative of the true values due to the effects of thread lubrication and frictional force of the fastener face on the bolting surface. Swaged fasteners are installed strictly in tension at an optimum preset tensile load. The positive clamping values are reliably consistent. Installation error is minimal. Replaceable, non-structural components may be installed with conventional fasteners.
Anticipated operating and maintenance costs over the productive life of a processing plant design significantly influence the go or no-go decision to build the plant. Large vibrating screens can both add to and reduce the magnitude of these costs. Plant designers must examine the serviceability of these large units. This includes the complexity of installation, start-up, routine maintenance, major repairs, and operating instrumentation. In assessing these costs, the likely condition exists somewhere between the extreme of a screen leaping momentarily out of position long enough to repair itself and swarms of mechanics covering the unit like bees on honey over several production-robbing shifts.
As larger vibrating screens are used, their size will exceed cost-effective shipping limits fully assembled. Screen manufacturers will join the ranks of other major equipment suppliers in on-site assembly and testing of these units. The incremental costs associated with these efforts must be considered in evaluating the plant construction and start-up costs.
The use of larger vibrating screens results in the dependence of a larger percentage of total plant production on each unit. It is imperative that plant operators maximize the production availability of large screens. This effort is enhanced by carefully planned operating and maintenance procedures. Since volumes have been published on efficient and successful preventative maintenance programs, this discussion will not deal with that topic. There are several suggestions that can be made to help potential big screen users better position themselves to react to the service requirements of these units.
As trite as it sounds, talk to potential screen suppliers specifically about the service requirements of their screens. Determine how recently a manufacturer has entered the wide screen market. Was this entry preceded by years of research and testing? There are generally two major shortfalls in a hastily planned new product introduction. Invariably, replacement parts availability is a problem. Second is the frustrating response to a frantic maintenance question, The only guy who knows that unit is on an island in Indonesia. Solidly planned programs will have organizational depth.
The labor pains, which have normally accompanied the birth of new vibrating screen designs, have been no less severe with the gradual introduction of large, high-capacity screens. More difficulty would have been encountered without the aid of advanced engineering and manufacturing techniques.
The development of vibrating screens over the last century has seen many variations to suit the exacting requirements of industry. Indeed, as each year passes, industry has presented the challenge to screen manufacturers of supplying larger machines than those used in the past and the question is often posed what is the maximum limit?
Innovations introduced such as bouncing ball decks, heated decks, tri-sloped and bi-sloped decks and pool washing features have all sought to achieve improved anti-blinding results and improved capacity for a given screening efficiency. Although the benefits achieved by the inclusion of these features were shown in some cases to be beneficial, the application of good throw in conjunction with the required G force in the operation of the screen has proven in screen performance today, to provide maximum screening efficiency and capacity. The importance of good throw is often overlooked and should be the first consideration when wishing to maximize screen capacity.
For a straight line motion screen the throw is the distance between the extremities of motion. For a circular motion screen, the throw is measured across the diameter of motion but if the screen has an oval motion, throw is measured by taking the mean of the major and minor axes.
The throw which is specified for a particular application is determined on a screen body eccentric weight basis and normally does not take into allowance the load of material which will be handled by the vibrating screen.
Therefore it is imperative that the live weight of the vibrating screen is sufficient to maintain, within reason, the throw which has been originally specified so as to effectively handle the loads being fed to the screen.
The above comments relate essentially to a dry screening application but in wet applications where metalliferous pulp is received on the screen, the benefits of a large throw in terms of increased screen capacity have been demonstrated in commercial practice. The ideal machine for receiving pulp for wet screening or desliming, dewatering etc. is a horizontal screen. Among other reasons, the horizontal screen provides the benefit of long retention time for handling the pulp. Also the straight line motion provided with good throw imparts a positive breaking of surface tension present between the pulp and the screen deck within the apertures.
The inclusion of large vibrating screens in the design of new plants by planning engineers and metallurgists responsible for such work, particularly where large associated equipment is available, is inevitable and is in fact a progression of size we have witnessed over the years.
We should remind ourselves that size progression could not proceed without the accumulation of experience in screen body design, in application knowledge, improved quality of manufacture and refinements of mechanism design with regard to achieving improved bearing life which allows the use of a good G force.
As referenced previously G force and throw are interrelated and therefore with the good G forces available today in the modern vibrating screens, the way is clear to taking full opportunity of increasing throw to handle the high tonnages which can be expected and are currently experienced on large vibrating screens.
Where abrasion of the screen deck surface is severe as in most metalliferous mining applications, and the separation sizes are in the order of mm to 50 mm aperture sizes, polyurethane screen panels are now in common use because of their excellent resistance to wear. The trend in the use of polyurethane panels in the metalliferous mining industry is quite definite and in fact in the major mining operations in Australia at least, the use of polyurethane screening panels is firmly established.
With reference to metalliferous tailings the need for dewatering presents a new dimension. The amount of tailings produced is very much greater since some 98-99% of mined ore is rejected in tailings form compared with varying amount of 3 to 5% rejected in a coal washing operation. Furthermore with dewatering of metalliferous tailings, using equipment as mostly used in coal washing would present maintenance problems because of the more abrasive nature of the tailings and therefore for that reason it is customary to discharge all metalliferous tailings slurry to a dam.
The screen-cyclone system relies on the blinding tendency of the screen deck apertures for its success, using either stainless steel wedgewire or polyurethane deck panels in conjunction with the use of cross dams spaced every 120 cm along the deck surface. When considering the screen-cyclone system it is important to appreciate that the screen function is not one of separation at a given aperture size but bleeding of water through the restricted deck apertures caused by the semi blinding condition. That is, if the deck apertures were to remain completely free of blinding, which is not the case, practically all of the tailings would pass through the apertures in the first pass and would not allow the system to function.
The underflow from the primary cyclones should be deposited on the horizontal section of the screen deck at the feed end where the maximum of water should be removed with the assistance of an additional section of wedgewire located on a 45 inclined back plate to remove free water that has accumulated on top of the bed of slurry most solids having stratified to the deck surface. The underflow should be evenly distributed across the width of the screen at minimum velocity, so as to allow the full benefit of stratification provided by the screen.
The actual results from the initial test run taken on the pilot plant installed at Philex Mining Corporation, Philippines in March, 1980 are as follows using a gravitated flow of tailing slurry from the concentrator.
The problems involved in installing, maintaining, and operating large vibrating screens have been summarized and discussed, based on a survey of current use of such screens in selected North American mineral processing applications. Practical, effective solutions for the more serious common problems are described, along with some recommendations on design practice for specifying, selecting, and installing large screens.
In order to properly assess the information gathered through the survey questionnaire, the results pertaining to each group of applications will be presented and discussed separately in the following section. The small number of installations actually surveyed makes any rigorous statistical interpretation of the data difficult, therefore the information is presented in a generalized fashion. Notwithstanding the small sample of operations as compared to the total number of such large screen installations around the world, the results are felt to fairly represent typical operating, maintenance and installation problems and practices in the sectors of the mineral processing industry the survey covered.
The results reported in this section refer to inclined vibrating screens used in conventional crushing and screening plants. Four operations replied to the survey questionnaire, all four are medium sized producers, primarily of copper concentrate, some with significant by-product production of Mo or Ag. Daily throughputs range from 5,300 tons to 38,000 tons.
The major problem areas reported by the users of these screens were bearing failure and replacement and side plate cracking. The minor problems reported were loose bolts, seals and routine wear items such as cloth and liner changes. Reported availability of the screens ranged from 92-96%. At one operation, the crushing and screening plant is oversized and operates only one shift per day, therefore downtime for maintenance is readily available and actual availability was not reported.
The maintenance of large vibrating screens in conventional crushing applications would normally consist of the regular replacement of wear parts, such as liners and screen cloths, as well as regular lubrication of the bearings and other moving parts as recommended by the manufacturer of the particular screens in use.
The operations with large horizontal vibrating screen installations replying to the survey questionnaire were Syncrude Canada Ltd., Climax Molybdenun (Henderson Operations), Quintana Minerals and Fording Coal Ltd. As previously noted, the screen applications at these operations are all basically very similar, involving wet screening of relatively large tonnages of slurry feed.
The major problem areas with these screen installations once again include bearing failure and side plate cracking in three out of the four installations. The fourth installation, Henderson, reported major problems with the mounting springs and feed lip both of which have presently been rectified to the point where only minimal unscheduled downtime occurs.
The major problems associated with the horizontal screens were with bearings and side plate cracking, and were evident soon after commissioning. Major efforts were undertaken at all the operations to correct the serious problems.
Large vibrating screens are normally selected for applications where multiple screens would be more costly to purchase and install. There have been a considerable number of large screen installations in a variety of mineral processing applications, therefore a considerable amount of operating data with respect to the screen components and performance has been gathered. From the plant designers viewpoint the design of a screen installation should consider the following areas:
The design of a large vibrating screen installation requires close attention to not only the screen itself, but also to the ancillary structures, maintenance procedures and personnel comfort and protection.
Large vibrating screens represent a considerable investment in equipment alone. In addition the loss due to interrupted production should one of these units go out of service can be economically much more severe. As plant tonnages have risen and larger equipment has been utilized in single trains or a small number of multiple trains, the risk of having a single large screen down for any length of time has become too great to ignore.Get in Touch with Mechanic