spiral classifier for mineral processing

spiral classifier for mineral processing

In Mineral Processing, the SPIRAL Classifier on the other hand is rotated through the ore. It doesnt lift out of the slurry but is revolved through it. The direction of rotation causes the slurry to be pulled up the inclined bed of the classifier in much the same manner as the rakes do. As it is revolved in the slurry the spiral is constantly moving the coarse backwards the fine material will flow over the top and be travelling fast enough to be able to work its way downwards to escape. The Variables of these two types of classifiers are The ANGLE of the inclined bed, this is normally a fixed angle the operator will not be able to adjust it.

The SPEED of the rakes or spirals, the DENSITY of the slurry, the TONNAGE throughput and finally the SETTLING RATE of the ore itself.To be effective all of these variables must be balanced. If the incline is too steep the flow of slurry will be too fast for the rakes or spirals to separate the ore. If the angle is too flat the settling rate will be too high and the classifier will over load. The discharge rate will be lower than the feed rate, in this case. The load on the rakes will continue to build until the weight is greater than the rake or spiral mechanism is able to move. This will cause the classifier to stop and is known as being SANDED UP. If the speed of the rakes or spirals are too fast, too much will be pulled, out the top. This will increase the feed to the mill and result in an overload in either the mill or classifier as the circuit tries to process the increased CIRCULATING LOAD.

The DENSITY of the slurry is very important, too high the settling will be hampered by too many solids. Each particle will support each other preventing the heavier material from quickly reaching the bottom of the slurry. This will not allow a separation to take place quickly. The speed at which the slurry will be travelling will be slow and that will hamper effective classification. Another variable is the TONNAGE. All equipment has a limit on the throughput that anyone is able to process, classifiers are no different. This and the other factors will have to be adjusted to compensate for the last variable, the ore itself. Every ore type has a different rate of settling. To be effective each of the previous variables will have to be adjusted to conform to each ones settling characteristics.

The design of these classifiers (rake, spiral, screw) have inherent problems, First, they are very susceptible to wear, caused by the scrubbing action of the ore, that plus all of the mechanical moving parts create many worn areas to contend with. The other problem that these classifiers have is that they are easily overloaded. An overloaded classifier can quickly deteriorate into a sanded-up classifier. Once that happens the results are lost operating time, spillage and a period of poor Mineral Processing and Separation performance.

Another mechanical classifier is the spiral classifier. The spiral classifier such as the Akins classifier consists of a semi-cylindrical trough (a trough that is semicircular in cross-section) inclined to the horizontal. The trough is provided with a slow-rotating spiral conveyor and a liquid overflow at the lower end. The spiral conveyor moves the solids which settle to the bottom upward toward the top of the trough.

The slurry is fed continuously near the middle of the trough. The slurry feed rate is so adjusted that fines do not have time to settle and are carried out with the overflow .liquid. Heavy particles have time to settle, they settle to the bottom of the trough and the spiral conveyor moves the settled solids upward along the floor of the trough toward the top of the trough/the sand product discharge chute.

spiral classifier - mineral processing

spiral classifier - mineral processing

Spiral classifier and hydrocyclone are the main equipments for the classification operation of the concentrator. Although the rapid development of the cyclone once made the spiral classifier lose its market, but with the continuous changes in the requirements of the selection plant, it was found that the spiral classifier also has its advantages. The spiral centrifugal classifier has the advantages of strong continuous operation, large processing capacity, low energy consumption per unit output, and convenient maintenance. It can handle particles with a diameter of 1um-10mm. The horizontal spiral centrifugal classifier adopts the method of wet classification, and its processing capacity can reach 1~20 (m3 slurry) kg/h. It is widely used in minerals, metal powders, chemical raw materials, pigments, fillers, etc.

The screw classifier is based on the principle that the solid particles are different in size and specific gravity, so the settling speed in the liquid is different. Fine ore particles float in the water and overflow, and coarse ore particles sink to the bottom of the tank. Spiral classifier is widely used in beneficiation plant to match with ball mill to form a closed circuit circulation path to distribute ore sand. Filter the material powder milled in the mill, and then use the spiral piece to screw the coarse material into the ball mill inlet, and the filtered fine material is discharged from the overflow pipe. There are four classifiers: high weir single spiral and double spiral, submerged single spiral and double spiral.

The spiral classifier is widely used in the classification of the grinding circuit of the concentrator and the operations of washing, desilting and dewatering. Its main advantages are simple equipment structure, reliable work and convenient operation.

1. It is used for the separation of machine-made sandstone powder, which can control the content of machine-made sandstone powder very conveniently and meet the requirements of users.2. It is suitable for dry technology large and medium-sized sand production lines.3. The content of 0.000.75mm stone powder can be adjusted between 2%-15%.4. Stone powder quality is easy to control, fineness adjustment is convenient, flexible and reliable.5. Using frequency conversion control technology, the operation is more concise.6. It can be connected with the mill in the closed circuit of the grinding circuit. Compared with hydrocyclone, the power consumption is lower.7. The main disadvantage is that the classification efficiency is low, the equipment is bulky, and the floor space is large. Due to the limitations of equipment specifications and production capacity, it cannot generally form a closed circuit with a ball mill of 3.6m or more.

The spiral classifier is divided into two types: high weir type and submerged type. High weir classifier is suitable for coarse particle classification, the maximum size of overflow is generally 0.4~0.15mm; submerged classifier is suitable for fine particle classification, the maximum size of overflow is generally below 0.2mm.

ekcp

ekcp

EIMCO-K.C.P. Spiral Classifiers is art of separating the solid particles in a mixture of solids and liquid into fractions according to particle size or density by methods other than screening. In general, the products resulting are (1) a partially drained fraction containing the coarse material (called the underflow) and (2) a fine fraction along with the remaining portion of the liquid medium (called the overflow). The classifying operation is carried out in a pool of fluid pulp confined in a tank arranged to allow the coarse solids to settle out, whereupon they are removed by gravity, mechanical means, or induced pressure. Solids which do not settle report as overflow. EIMCO-K.C.P. Spiral Classifiers are mechanically the devices are powerfully built, and functionally they are versatile and flexible. Todays worldwide acceptance of EIMCO-K.C.P. Classifiers for washing and dewatering pulps, and in closed-circuit grinding is the result of many years of experience in solving wet classification problems. Because users needs vary so greatly, the Classifier is available in a wide range of spiral diameters and pitches, tank shapes and lengths allowing exact compliance with each users classification requirements. Spiral diameters (0.3 m to 2.25 m): Important in establishing a correct balance between overflow and raking capacity. Bears directly on accuracy of separation and control of agitation. Spiral pitches (single / double / triple): Number of ribbons is a factor in controlling degree of agitation. Each ribbon of advanced pitch gives greater raking capacity than equivalent ribbon of spiral using lesser pitch. Triple ribbon spiral highly advantageous for slow-speed operations requiring close separations and high raking capacities. Adjustable spiral speeds: Recommended speed of operation given in peripheral MPM is an individual consideration for each ore, and is governed by size, shape and gravity of particle, angle of repose of raking load and desired mesh of separation. Peripheral speeds between 6 and 60 meters per minute are available. Pool depth: Choice of pool depth is directly related to effectiveness of pool area. Series 90 units are employed for coarse separations on down to 212 micron (65 mesh); Series 125 units are employed for separations between 300 and 106 micron (48 and 150 mesh); Series 150 units are employed for separations of 150 micron (100 mesh) and finer. Lifting device: Lifting device eliminates necessity of draining tank during shutdowns. Classifier may be quickly put in operation after shutdown with tank fully sanded. Hydraulic-type standard on all units 1.2 m in diameter and larger. Fast action hand wheel-operated screw- type lift standard on 1.05 m and smaller.

The EIMCO-K.C.P. equipment product line consists of Liquid Solid Separation products for the Mining, Mineral & Metallurgical Process, Chemical Process, Food Process, Refinery, Pulp and Paper, Power Plant, FGD System, Municipal & Industrial Waste and Water Treatment and with a wide range of related services.

an operational model for a spiral classifier - sciencedirect

an operational model for a spiral classifier - sciencedirect

Wash water addition and concentrate port openings are used to tune spiral operation.There is no mathematical model describing the action of wash water and concentrate ports on spiral performances.A semi-empirical model is proposed to account for these operating variables.

Spirals are gravity concentrators used for the valorization of coal and heavy minerals. Coarse hematite iron ores in Canada are usually concentrated by spirals. Spirals classify the particles according to their size and specific gravity. Several mathematical models were proposed to simulate the operation of spirals using a balance between the various forces acting on particles. However few models provide a method to account for wash water addition and the opening of concentrate ports that are two strategic variables for the operation of spiral classifiers. This paper proposes a model to incorporate these variables in a simulation scheme and validates the model with pilot plant data.

three factors affect the classifying effect of spiral classifier - xinhai

three factors affect the classifying effect of spiral classifier - xinhai

The spiral classifier is one of the important mineral processing equipment, whose working principle is to classify the materials by using the difference in the settling speed of solid particles in the liquid. The classifying effect of the spiral classifier will directly affect the content of the qualified product in the returned sand, thus affecting the grinding efficiency of the grinding mill.

In the classifying process, the factors that affect the classifying effect of the spiral classifier mainly include the following three aspects: the feeding of the spiral classifier, the structure of the spiral classifier and the operation mode of the spiral classifier. Below, we will specifically analyze how these three factors affect the classifying effect of spiral classifier.

The larger mud content or the finer particle sizes in the feed are, the stronger slurry viscosity is, and the slower settling speed of ore particles in the slurry will be, thus the particle size of overflow products is coarse.

In this case, in order to obtain the required overflow fineness, the supplementary water can be appropriately increased to reduce the pulp concentration. If the amount of mud in the feed is small or the slurry has been deslimed, the slurry concentration should be increased appropriately to reduce the number of fine particles in the returned sand.

There are three main factors that affect the classifying efficiency of the spiral classifiers: the inclination angle of the groove, the height of the overflow weir and the rotation speed of the spiral.

The inclination angle of the groove affects the settling area of the classifier. But because the groove of the spiral classifier is fixed after the installation, the inclination angle of the groove should be adjusted to an appropriate angle. The installation angle of classifier equipment is generally between 16-18 is appropriate.

If the inclination angle is too large, the settlement area decreases, and the coarse material is easy to slide, the overflow particle size will be coarser, but the fine material in the returned sand will decrease accordingly. On the contrary, if the inclination angle is too small, the settlement area is large and the overflow particle size is fine, so the fine material in the returned sand will increase. Therefore, the inclination angle should be determined comprehensively according to the nature of materials, classifying fineness and other factors.

The common spiral classifiers mainly include high weir spiral classifier and submerged spiral classifier. The high weir spiral classifier is suitable for the classification of the coarse particle, and the particle size of classifying overflow is generally larger than 0.15mm. The submerged spiral classifier is suitable for the classification of fine particle, and the particle size of classifying overflow is generally less than 0.15mm. The common feature of both is that the height of overflow weir will affect the subsidence area. When the overflow weir is increased, the subsidence area is increased, the volume of the classifier is increased, but the overflow particle size is decreased. In general, the height of overflow weir is rarely changed once it is adjusted at the beginning of production. For high weir spiral classifiers, the height range of overflow weir is usually controlled in the range of 400-800mm, while the height range of overflow weir is generally between 930-2000mm for the submerged spiral classifiers.

In addition, the rotating speed of the spiral will directly affect the agitation degree of the liquid surface and the capacity of conveying sand return. In the production, the overflow fineness and the productivity of sand return must meet the requirements. The faster the rotating speed is, the higher the capacity of returning sand is, but the increasing agitation effect will make the coarse particle sizes in the overflow increase. In general, the rotating speed of the spiral should be controlled within the range of 1.5-10r/min.

The pulp concentration is an important regulating factor, which has a great influence on the overflow fineness of spiral classifiers in actual production. Decreasing the pulp concentration, the overflow particle size becomes smaller, and the concentration increases, the overflow particle size also becomes coarser. Therefore, keeping a certain overflow particle size under an appropriate concentration can obtain the ideal production index. The suitable concentration of critical separation size can be determined by the mineral processing test.

The feeding amount of the spiral classifier should keep even and stable, otherwise, it is easy to cause the unstable classifying concentration. The classifying fineness fluctuates frequently, which can affect the production index of the next operation.

To sum up, the classifying effect of the spiral classifier involves many aspects, including the feeding of the spiral classifier, the structure of the spiral classifier and the operation mode of the spiral classifier. The mineral processing equipment technical experts suggest: first, please choose the formal mineral processing equipment manufacturers to buy the spiral classifiers, which can ensure the quality of equipment; In addition, in the daily production, the spiral classifier operators must pay more attention to the running state of the spiral classifier, take appropriate measures after analyzing the abnormal situation for ensuring the smooth operation of the spiral classifiers and obtaining the good classifying effect.

spiral classifier manufacturers, spiral classifier operation - xinhai

spiral classifier manufacturers, spiral classifier operation - xinhai

High spiral classifier operation: the grinded pulp is fed into a tank from the inlet in the middle of settlement region, and the slurry classification sedimentation area is under the inclined tank. The spiral with low-speed rotation stirs the slurry, so that the fine particles rise, and the coarse particles sink to the bottom of the tank. The overflow weir is above the bearing center which is under screw shaft, and is underneath overflow end.

spiral separator, spiral classifier manufacturers, spiral classifier operation

spiral separator, spiral classifier manufacturers, spiral classifier operation

The overflow spiral blade is higher than overflow level, and the overflow spiral center is lower than overflow surface. The high wire spiral classifier is applied in the classification of ore with particle size 0.83-0.15mm

The grinded pulp is fed into tank from the inlet in the middle of settlement region, and the slurry classification sedimentation area is under the inclined tank. The spiral with low speed rotation stirs the slurry, so that the fine particles rise, and the coarse particles sinks to the bottom of tank. Overflow weir is above the bearing center which is under screw shaft, and is underneath overflow end.

spiral separator, spiral classifier manufacturers, spiral classifier operation 
 - xinhai

spiral separator, spiral classifier manufacturers, spiral classifier operation - xinhai

The overflow spiral blade is higher than overflow level, and the overflow spiral center is lower than overflow surface. The high wire spiral classifier is applied in the classification of ore with particle size 0.83-0.15mm

The grinded pulp is fed into tank from the inlet in the middle of settlement region, and the slurry classification sedimentation area is under the inclined tank. The spiral with low speed rotation stirs the slurry, so that the fine particles rise, and the coarse particles sinks to the bottom of tank. Overflow weir is above the bearing center which is under screw shaft, and is underneath overflow end.

installation operation and maintenance of spiral classifier | lzzg

installation operation and maintenance of spiral classifier | lzzg

Guidance on installation, operation and maintenance of spiral classifier Installation The screw classifier can be installed after inspection without damage or loose screws. The classifier should be firmly installed on the basis of the poured concrete. The basic design should have a good supporting effect and minimize the shear force on the screws. Operation The machine can only be operated after the structure and working principle of the spiral classifier are clear. After the spiral body rotates, it can start to feed ore slurry, gradually feeding the amount of ore. When the spiral body is in working state, if it encounters special faults such as jamming or overload), it must be stopped immediately, immediately lift the spiral body out of the slurry surface, never allow the spiral body to be pressed in the slurry, and quickly open the mine valve to avoid siltation. When starting again, the spiral body must be lowered to a certain position in order to rotate the spiral body. If the machine needs to be stopped during use, the feed should be stopped first, and the operation can only be stopped after the material stage is graded and there is no material in it. Maintenance All lubrication points are lubricated with sodium-based grease or calcium-based grease. Each shift should check whether the lubricating oil inside the reducer is on the marking line of the oil needle, and change the oil every 6 months. Always check the lower support or intermediate frame bearings, bearings, sealing rings for wear and damage to the bearings for timely replacement. Bearing lubrication must be filled with high pressure oil into the bearing with a manual dry oil pump every 4 hours to maintain the sealing performance of the bearing.

The screw classifier can be installed after inspection without damage or loose screws. The classifier should be firmly installed on the basis of the poured concrete. The basic design should have a good supporting effect and minimize the shear force on the screws.

The machine can only be operated after the structure and working principle of the spiral classifier are clear. After the spiral body rotates, it can start to feed ore slurry, gradually feeding the amount of ore. When the spiral body is in working state, if it encounters special faults such as jamming or overload), it must be stopped immediately, immediately lift the spiral body out of the slurry surface, never allow the spiral body to be pressed in the slurry, and quickly open the mine valve to avoid siltation. When starting again, the spiral body must be lowered to a certain position in order to rotate the spiral body. If the machine needs to be stopped during use, the feed should be stopped first, and the operation can only be stopped after the material stage is graded and there is no material in it.

All lubrication points are lubricated with sodium-based grease or calcium-based grease. Each shift should check whether the lubricating oil inside the reducer is on the marking line of the oil needle, and change the oil every 6 months. Always check the lower support or intermediate frame bearings, bearings, sealing rings for wear and damage to the bearings for timely replacement. Bearing lubrication must be filled with high pressure oil into the bearing with a manual dry oil pump every 4 hours to maintain the sealing performance of the bearing.

Applycation of sand classifer Beneficiation The spiral classifier is one of the equipment for beneficiation. The spiral classifier is a machine for mechanical classification based on the principle that the specific gravity of solid particles is different, so the speed of precipitation in the liquid is different. The material and powder ground out of the mill can be filtered, and

The spiral classifier is used in the artificial sand production line and the commonly used classification equipment in the washing operation. It is mainly used to wash off the mud powder in the sand so that the artificial sand can reach the standard of construction sand. Some faults will inevitably occur during work and use. Here are some common fault

This project adopts self-developed new technologies, new processes and new equipment, and eliminates outdated technologies, processes, equipment and production capacity. The new type of pulping machine developed in this project is used for the dispersion of minerals in the process of raw material pulping, which is shorter than the original pulping time, and the separation of minerals and impurities is

The mineral separation spiral classifier is used in the dressing plant to match with the ball mill to distribute the ore sand, or in the gravity dressing plant to classify the ore and mud. The particle size classification of the slurry in the metal beneficiation process and the desilting and dewatering of the washing Wait for homework. This machine has

spiral classifiers | screw classifiers | dove

spiral classifiers | screw classifiers | dove

DOVE Spiral Classifier, also referred to as Screw Classifier, or Spiral Mineral Separator, is highly efficient classifier designed for closed circuit wet classification and separation of the Slimes (Fines) from a sandy sized (Coarse) material. It is well suited for classification, where a two product size-split is required. Due to inherent operational qualities, DOVE Spiral Classifier is ideally suited Sizing applications, Washing Applications, and Dewatering sand or crushed material from Hydro cyclone, or lower screen residues.

DOVE Coarse and Fine Spiral Classifiers are supplied in various capacities, tub lengths, screw sizes and technical specifications. We supply total of 16 models, where 10 models are configured with single screw and 6 models with dual screw.

Spiral Screw classifier is a type of common mechanical classifier, consists primarily of an inclined tub and a transport screw for the coarse material. The fine material residue is at the lower end of the tub and the coarse material residue is at the upper end. The principle of the operation and separation of solid grains is based on the law of gravity and concept that the solid particles are different in size and specific gravity, therefore the settling speed in the water is different. Fine ore particles float in the water and overflow, and respectively coarse ore particles settles to the bottom. As a guide line, a unit with longer length classifier will dewater the same material to a higher degree, and likewise a unit with a greater diameter of screw revolving the identical speed will produce higher capacity. In the application of dewatering fine material, the screw speed is reduced to allow proper classification and dewatering.

DOVE laboratory will assay your ore samples rapidly and analyze your raw materials and recommend the most efficient processing plant according to the ore specifications, minerals composition, and ore assay results, and your project size and the geologic and topographic conditions of your mine.

WE HIGHLY RECOMMEND FORWARDING SOIL SAMPLES OF YOUR MINE TO US FOR ANALYSIS, IN ORDER TO DESIGN AND RECOMMEND THE MOST EFFICIENT PROCESSING PLANT, TAILOR MAID TO YOUR MINE REQUIREMENTS, FOR HIGHEST PRODUCTION RECOVERY.

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