spiral classifier | screw classifier - jxsc machine
The Spiral Classifier is available with spiral diameters up to 120. These classifiers are built in three models with 100%, 125% and 150% spiral submergence with straight side tanks or modified flared or full flared tanks. The spiral classifier is one of the size classifying equipment for the mining industry. It is a kind of equipment for mineral classification based on the principle that the specific gravity of solid particles is different and the speed of precipitation in the liquid is different. It can filter the material powder from the mill, then screw the coarse material into the mill inlet with the spiral slice, and discharge the filtered fine material from the overflow pipe. Spiral classifier short for the classifier. The classification machine mainly has the high weir type single screw and the double screw, the sinking type single screw and the double screw four kinds of classification machines. The classifier is mainly composed of a transmission device, a spiral body, a trough body, a lifting mechanism, a lower bearing (Bush) and a discharge valve. Spiral classifier is widely used in mineral processing plants with a ball mill as a closed-circuit circuit to separate the flow of ore sand, or used in gravity concentrator to grade ore sand and fine mud, and metal beneficiation processes to grade the size of ore pulp and washing operations in the desliming hopper, dehydration and other operations.
Spiral classifier features: 1. Low power consumption; 2. Heavy-duty, long working life; 3. Powerful self-contained spiral lifting device; 4. Continuous spiral raking; 5. High classifying efficiency; 6. Wide choice of weir height; 7. Rigid tank and substructure; 8. Wide choice of tank design; 9. A wide range of industries serviced.
Spiral classifier is by means of solid particles of different sizes, the proportion of different, thus settling velocity in liquids of different principles, fine mineral particles floating in the water to overflow out of coarse mineral particles sink to the bottom. Discharged from the screw into the upper part, to a hierarchical classification of mechanical equipment, can mill to grind the material powder level in the filter, and then use the course material helical screw rotary vane into the mill feed, the filter out the fine material is discharged from the overflow pipe. The machine base is made of a channel steel body with steel plates welded together. Into the head of the screw shaft, shaft, using pig iron, wear-resistant and durable, lifting devices of electric and manual. The main types of the spiral classifier are high Weir single screw and double screw, low weir single screw and double screw, sinking single screw and double screw Mainly High Weir type and sinking type and XL spiral classifier.
classifiers,screw classifiers,spiral separator,china spiral classifier,spiral classifier price,ore spiral classifier - hongxing machinery
There are four types of classifiers, high weir type single and double spiral classifier, immersed single and double spiral classifier. Spiral classifier (Screw classifier) is widely used for distributing ore in the close circuit with ball mill. Advantages are simple structure, reliable working condition and convenient operation.
To be successful in a obtaining a uniform grind that is necessary to achieve a high percentage of recovery it is necessary to control the degree of fineness that the ore is reduced to. This is done by separating the fine material from the course and regrinding the coarse until it is fine enough for efficient mineral extraction.
To be able to obtain the necessary control over the amount of grinding required, a method of effective classification and separation by size must be available. For maximum effectiveness it should take place after every stage of grinding.
The types of equipment that are used to accomplish this are called CLASSIFIERS. There are three basic kinds used. The first two, the RAKE classifier and the SPIRAL or screw classifier work on the same principal, and are not often used any more. These two types were popular for many years. It wasnt until the development of the CYCLONE type classifier that their popularity faded. You may still find a few though, in the older mills and the mills that require a classification of the larger ore sizes that the cyclones are not very good at sizing.
Both the rake and spiral classifiers take advantage of the natural settling characteristics of ore. Any time that slurry is allowed to flow over a surface the tendency of the ore is to graduate itself into layers of different sized material. The larger sizes will be on the bottom, these are also the ones that are the slowest moving. As you come closer to the surface, the material will become smaller and faster until the very finest and the easiest to wash away is on top.
To understand how these two classifiers make use of this settling action, a description of them is required. First, to have the classification happen, the slurry must be able to flow. This means the classifiers must be inclined. The working portion of these two classifiers are the RAKES or SPIRAL/screw which are placed into the flow of ore. To separate the course material from the fine, the rakes and spiral make use of the same theory, but differ in its application. The theory is, as the slurry flows down the inclined bed of the classifier it will separate into different sizing. The larger ore that is on the bottom will not be flowing as fast as the light ore on top.
To separate the two, the rakes and the spiral will pull the all of the slurry back up the incline, then, let it go to flow back down towards the underflow or in this case the fine ore discharge point. The smaller, faster ore will be able to travel a longer distance than the large particles before the rakes or spiral will pull the ground material back towards the coarse ore discharge. If the Classifier is able to pull the course ore backwards further than it can travel forwards, then eventually the bigger particles will be pulled all the way to the top of the incline where they will be discharged. The smaller faster pieces of ground rock will end up at the bottom of the incline to be discharged as fine material that is ready for the next stage of processing.
This type of classifier will do away with the necessity of pumps. The length of the incline that is needed is long and steep enough to have the material lifted to the feed end of the mill. The flow of the finer ore will run down hill to the next piece of equipment.
The concentrator that used this type of classification was built on the side of a hill to make use of gravity to get the material from one stage of production to the next. It was because of this that this type of concentrator was referred to as a GRAVITY FLOW/MILL. I used the past tense in this paragraph because this design of mill is no longer in use.
I want to know what is the range of the % Solids content in overflow from screw/spiral classifier in Hematite Iron ore washing for efficient operation of classifier. I also want to know what is Auto dilution in thickener. Does Auto dilution has any effect on Pumping capacity of clarified water from thickener.
Each operation is different, but the good news is that you can simply determine the solids % wt. in the SOF, try 2 -3 times daily over one week, get a profile. If below 5% wt., you may not need auto dilution, also depending on ore and grind size. This is almost a clarifier regime, often workable without rakes in certain units. Above 5% in general start looking at auto-dilution before adding the flocculant do this off-line. Make sure that the thickener underflow (TUF) discharge comes out continuously, otherwise you may need to play with the lifters, if you have them. The UF solids % wt. must be correlated with the yield stress.look for 30 Pa high-end cut off value for lean operation. When the ore or grind size changes, you need to repeat the evaluation.
My take on these classifiers is that the clear water added to the classifier feed determines the size of the largest heaviest particle going to the overflow. This is the criteria that you should be working to achieve. As you probably have more than one classifier reporting to the thickener you will need to perform the solids percent in each overflow. As you add water to the classifier feed, the separation efficiency increases. You should be raising or lowering the discharge weir to attain the desired size cut. Only if the thickener becomes overloaded should you add water. Pumping excess water adds cost and wear to pump trains.
Pulp density of the Overflow defines % of solids in thickener. This solids% depends also up on quality of recycle water used in spiral processto know quantum of solids..you have to give feed quantity and underflow quantity.
The % solids in classifier overflow may vary in wide range, its all depends on your ore characterisation and operating variables. For the same operation we used to get 15-18% solids as my ore contains too much fines & this is not end process in our case.Try to concentrate on end products. Do not let go valuables in your final tailings.
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.
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 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.
spiral classifier | stone crusher and mill
1. Simple structure, reliable running and easy operation.2. It mechanically classifies through the mechanism of different sedimentation speed of solid particle in liquid due to different size and different specific gravity.3. It can classify the ground material powder from the grinder, spiral the coarse grain into material inlet of grinder through the spiral chip, and discharge the classified fine grain from overflow surface.4. Its base is made from channel steel, and its body is welded from steel plate.5. The lower support of spiral bearing is of engine-bearing structure of good wear-resistance and durability.6. The lifting device is of electric and manual mode.
Fine ore pulps are fed into water tank through the feeding opening located in the center of settling zone. Beneath the inclined water tank is the ore pulp classification zone where ore pulps are stirred by low-speed impellers. Fine ore particles are lifted up and then spilled out the overflow opening,coarse ore particles precipitate down to tank bottom and are discharged via discharge opening.The position of the overflow opening is higher than the bearing centre where in the bottom of the screw shaft,and lower than the upper edge of overflow spiral.