chrome ore, chrome recovery, chrome mineral, chrome mining process - xinhai
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.
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
Chrome ore deposits are mined by both underground and surface techniques. most chrome ore must be processed by the chrome ore processing plants. the mainly chrome ore beneficiation method is gravity separation. so the mainly used chrome ore concentrating equipments are ore washbox (sometimes it is called jigger), concentrating table, spiral classifiers, etc.
1.Large raw chrome ore for primary crushing are fed into the jaw crusher by Plate feeder and are reduced to 8 inches or smaller. After first crushing, the material will transferred to cone crusher by belt conveyor for secondary crushing; the crushed chrome ore stone will then transferred to vibrating screen for classifying. After classifying, the parts whose size below the mesh size will be transferred away as final products, while the other parts will return to cone crusher, thus forming a closed circuit. Size of final products can be combined and graded according to your specific requirement.
3. Screened products are transported to the jig for rough separation and to three concentrating tables for fine separation. Then, tailings are delivered into the jig in the next stage for screening for 4 times like this. All tailings in the concentrating table are sent to tailings reservoir after tailings dry stacking.
ball mills | industry grinder for mineral processing - jxsc machine
Max Feeding size <25mm Discharge size0.075-0.4mm Typesoverflow ball mills, grate discharge ball mills Service 24hrs quotation, custom made parts, processing flow design & optimization, one year warranty, on-site installation.
Ball mill, also known as ball grinding machine, a well-known ore grinding machine, widely used in the mining, construction, aggregate application. JXSC start the ball mill business since 1985, supply globally service includes design, manufacturing, installation, and free operation training. Type according to the discharge type, overflow ball mill, grate discharge ball mill; according to the grinding conditions, wet milling, dry grinding; according to the ball mill media. Wet grinding gold, chrome, tin, coltan, tantalite, silica sand, lead, pebble, and the like mining application. Dry grinding cement, building stone, power, etc. Grinding media ball steel ball, manganese, chrome, ceramic ball, etc. Common steel ball sizes 40mm, 60mm, 80mm, 100mm, 120mm. Ball mill liner Natural rubber plate, manganese steel plate, 50-130mm custom thickness. Features 1. Effective grinding technology for diverse applications 2. Long life and minimum maintenance 3. Automatization 4. Working Continuously 5. Quality guarantee, safe operation, energy-saving. The ball grinding mill machine usually coordinates with other rock crusher machines, like jaw crusher, cone crusher, to reduce the ore particle into fine and superfine size. Ball mills grinding tasks can be done under dry or wet conditions. Get to know more details of rock crushers, ore grinders, contact us!
Ball mill parts feed, discharge, barrel, gear, motor, reducer, bearing, bearing seat, frame, liner plate, steel ball, etc. Contact our overseas office for buying ball mill components, wear parts, and your mine site visits. Ball mill working principle High energy ball milling is a type of powder grinding mill used to grind ores and other materials to 25 mesh or extremely fine powders, mainly used in the mineral processing industry, both in open or closed circuits. Ball milling is a grinding method that reduces the product into a controlled final grind and a uniform size, usually, the manganese, iron, steel balls or ceramic are used in the collision container. The ball milling process prepared by rod mill, sag mill (autogenous / semi autogenous grinding mill), jaw crusher, cone crusher, and other single or multistage crushing and screening. Ball mill manufacturer With more than 35 years of experience in grinding balls mill technology, JXSC design and produce heavy-duty scientific ball mill with long life minimum maintenance among industrial use, laboratory use. Besides, portable ball mills are designed for the mobile mineral processing plant. How much the ball mill, and how much invest a crushing plant? contact us today! Find more ball mill diagram at ball mill PDF ServiceBall mill design, Testing of the material, grinding circuit design, on site installation. The ball grinding mill machine usually coordinates with other rock crusher machines, like jaw crusher, cone crusher, get to know more details of rock crushers, ore grinders, contact us! sag mill vs ball mill, rod mill vs ball mill
How many types of ball mill 1. Based on the axial orientation a. Horizontal ball mill. It is the most common type supplied from ball mill manufacturers in China. Although the capacity, specification, and structure may vary from every supplier, they are basically shaped like a cylinder with a drum inside its chamber. As the name implies, it comes in a longer and thinner shape form that vertical ball mills. Most horizontal ball mills have timers that shut down automatically when the material is fully processed. b. Vertical ball mills are not very commonly used in industries owing to its capacity limitation and specific structure. Vertical roller mill comes in the form of an erect cylinder rather than a horizontal type like a detachable drum, that is the vertical grinding mill only produced base on custom requirements by vertical ball mill manufacturers. 2. Base on the loading capacity Ball mill manufacturers in China design different ball mill sizes to meet the customers from various sectors of the public administration, such as colleges and universities, metallurgical institutes, and mines. a. Industrial ball mills. They are applied in the manufacturing factories, where they need them to grind a huge amount of material into specific particles, and alway interlink with other equipment like feeder, vibrating screen. Such as ball mill for mining, ceramic industry, cement grinding. b. Planetary Ball Mills, small ball mill. They are intended for usage in the testing laboratory, usually come in the form of vertical structure, has a small chamber and small loading capacity. Ball mill for sale In all the ore mining beneficiation and concentrating processes, including gravity separation, chemical, froth flotation, the working principle is to prepare fine size ores by crushing and grinding often with rock crushers, rod mill, and ball mils for the subsequent treatment. Over a period of many years development, the fine grinding fineness have been reduced many times, and the ball mill machine has become the widest used grinding machine in various applications due to solid structure, and low operation cost. The ball miller machine is a tumbling mill that uses steel milling balls as the grinding media, applied in either primary grinding or secondary grinding applications. The feed can be dry or wet, as for dry materials process, the shell dustproof to minimize the dust pollution. Gear drive mill barrel tumbles iron or steel balls with the ore at a speed. Usually, the balls filling rate about 40%, the mill balls size are initially 3080 cm diameter but gradually wore away as the ore was ground. In general, ball mill grinder can be fed either wet or dry, the ball mill machine is classed by electric power rather than diameter and capacity. JXSC ball mill manufacturer has industrial ball mill and small ball mill for sale, power range 18.5-800KW. During the production process, the ball grinding machine may be called cement mill, limestone ball mill, sand mill, coal mill, pebble mill, rotary ball mill, wet grinding mill, etc. JXSC ball mills are designed for high capacity long service, good quality match Metso ball mill. Grinding media Grinding balls for mining usually adopt wet grinding ball mills, mostly manganese, steel, lead balls. Ceramic balls for ball mill often seen in the laboratory. Types of ball mill: wet grinding ball mill, dry grinding ball mill, horizontal ball mill, vibration mill, large ball mill, coal mill, stone mill grinder, tumbling ball mill, etc. The ball mill barrel is filled with powder and milling media, the powder can reduce the balls falling impact, but if the power too much that may cause balls to stick to the container side. Along with the rotational force, the crushing action mill the power, so, it is essential to ensure that there is enough space for media to tumble effectively. How does ball mill work The material fed into the drum through the hopper, motor drive cylinder rotates, causing grinding balls rises and falls follow the drum rotation direction, the grinding media be lifted to a certain height and then fall back into the cylinder and onto the material to be ground. The rotation speed is a key point related to the ball mill efficiency, rotation speed too great or too small, neither bring good grinding result. Based on experience, the rotat
ion is usually set between 4-20/minute, if the speed too great, may create centrifuge force thus the grinding balls stay with the mill perimeter and dont fall. In summary, it depends on the mill diameter, the larger the diameter, the slower the rotation (the suitable rotation speed adjusted before delivery). What is critical speed of ball mill? The critical speed of the ball mill is the speed at which the centrifugal force is equal to the gravity on the inner surface of the mill so that no ball falls from its position onto the mill shell. Ball mill machines usually operates at 65-75% of critical speed. What is the ball mill price? There are many factors affects the ball mill cost, for quicker quotations, kindly let me know the following basic information. (1) Application, what is the grinding material? (2) required capacity, feeding and discharge size (3) dry or wet grinding (4) single machine or complete processing plant, etc.
grinding - mineral processing
The final fineness of the product mainly depends on the number of times the ore particles pass through the grinder. The longer the grinding, the smaller the particle size. Separate crushing and grinding steps are necessary, the ball mill can only receive the broken ore particle, and then grind to the grinding fineness required for flotation.
In order to separate the concentrate from the ore, the ore should be ground fine enough to release the target mineral from the non-mineral grains. The degree of grinding required for this depends on the size of the mineral particles in the ore. A laboratory-scale flotation test is usually required on materials of different particle sizes to determine the grinding particle size required to release the target minerals.The fineness of the ore particles produced by grinding is crucial to recover the minerals by flotation. The most common grinding machines are semi-automatic (SAG) and automatic (AG) mills and ball mills.
Determining an optimal grinding size can maximize the recovery of target minerals in the subsequent flotation process.The grinding size is too large, and some ore particles and non-ore particles cannot be separated, thus preventing their flotation. If the particle size is too fine, the bubbles that rise during the flotation will push the very fine ore-containing particles away, preventing them from contacting the bubbles, thereby reducing their ability to be recovered into the concentrate.In addition, extremely fine rock and iron sulfide particles may agglomerate with extremely fine sulfide ore particles, preventing the ore particles from floating.
According to the test, the particles usually need to be ground to a diameter of about 100 mm to release minerals from each other. When the particles are less than about 10 mm, this is not conducive to the flotation effect.Grinding operations are very power-hungry, which is another reason to avoid excessive grinding.
The crushed products are ground in SAG or AG mills. The self-grinding machine can grind ore without grinding media such as iron ball, or steel rod, as long as the hardness of the ore is sufficient for the rolling ore to grind by itself.A large vibrating screen is used to sieve the ground products to separate the oversized particles. A small cone crusher to recover the oversized material, and then sent them return to the SAG or AG mill for re-grinding. The correct size material is sent to the ball mill for final grinding.
The ball mill is the fine grinding machine connect the SAG or AG mill and flotation machine. Ball mills produce fine particles with a uniform size for flotation, its grinding medias commonly are steel ball. The ball mill rolls grinding media together with the ore, as the ore grinds, these balls initially 5-10 cm in diameter but gradually wear out.Grinding is always carried out under wet conditions, with about 70% solid mixture in water.This procedure maximizes ore production and minimizes power consumption.
laboratory grinding mill
Our Laboratory Grinding Mill comes standard with a 1 HP motor and optional variable speed drive ranging from 1 to 100 RPM. This Grinding Mill is fully enclosed with sound dampening material for a quiet workplace. The sheet metal steel fabrication provides full enclosure around the main frame and door. The yoke (grinding cylinder) is totally balance and vibration-free in its horizontal position of operation. Minimal effort is needed to swing it from horizontal to vertical position (loading/unloading). A unique feature this grinding mill has is the possibility to use different cylinders for research or pilot plants tests. Specifically, we offer different size of cylinders from 5 (127mm) inside diameter by 12 (305mm) long to 9 (229mm) diameter by 22 (560mm) long. All grinding mills cylinders are fully interchangeable and can be mounted/ removed rapidly. The cover is of a unique design that automatically seals the cylinder and is quickly mounted/removed. Another feature of this Grinding Mill are its heavy duty castors (wheels) for ease of laboratory movement/mobility.
Ore Grinding Mills are used for the fine grinding as the last step in the reduction of an ore prior to concentration (gravity or flotation) or cyanidation. Practice varies, depending upon the type of ore and the amount of reduction required. In addition, some of the older properties continue with methods that perhaps are not considered the best in light of recent improvements but that cannot be economically changed because of capital outlay. Present grinding practice is closely linked with classification, so that some overlapping of subject matter occurs. In this chapter some of the theory of grinding, different types of equipment, and flow sheets are discussed.
Most of the tonnage milled today is ground in one of the following types of equipment or a combination of two or more: ball mills, tube mills, rod mills, and stamps. Chilean mills and Huntington mills are used only in a few isolated cases today.
The term ball mill is generally used to refer to a cylindrical mill whose length is less than, equal to, but not much greater than its diameter. It was initially developed for relatively coarse grinding, but by using it in closed circuit with a classifier its use has been extended for fine grinding.
Ball mills have shells of cast iron or steel plates and are carried on hollow trunnions. Ore is fed through a scoop, drum-type, or combination feeder at one end and is discharged from the opposite trunnion.
Ball mills may be arbitrarily classified into two types, according to the method of pulp discharge. In high-level or overflow mills the pulp level builds up until it overflows and discharges through the trunnion. High- level discharge mills are made by a large number of manufacturers throughout the world. Low-level mills are typified by the Allis-Chalmers andMarcy (see Figs. 14 and 15) grate-discharge mills. The discharge end is fitted with grates; between the grates and the end of the mill are radial lifters which act as a pump to lift the discharge to the hollow trunnion. Drive is by spur or herringbone gear, direct connected or belt driven.
Ball mills are built in sizes ranging from small laboratory mills to a present maximum of 12 ft. diameter by 12 ft. long, the latter requiring close to 1000 hp.Liners are usually of manganese steel, of chrome steel, or white iron, 3 to 6 in. thick. Corrugated and shiplap construction is commonly used to increase the grinding action.
The Hardinge mill (see Fig. 16) differs from most ball mills in that conical ends are added to the cylindrical portion of the mill. The cone at the feed end has a larger open angle than that at theopposite end. Its makers state that the large balls concentrate near the feed end of the mill where the coarsest ore collects and the smaller balls act on the finer ore.
Rod mills (see Fig. 17) follow the general dimensions of tube mills with diameters from 3 to 6 ft. and lengths from two to three times their diameter. They differ from ball mills in that steel rods 3 or 4 in. shorter than the mill length inside the liners are used as grinding media. Rod mills are often run on tires and rollers instead of trunnions or on one trunnion and one tire and set of rollers.
Low-level discharge is obtained on Marcy rod mills by having a beveled annular ring at the discharge end. A stationary steel door fits close to this beveled ring and serves to hold the rods in the mill while pulp discharges between the mill and the door.
The distinction between tube mills and ball mills is not somarked as their names indicate. Mills from 4 to 6 ft. in diameter and from 16 to 22 ft. long are usually termed tube mills. This was the first type of rotary mill for metallurgical purposes. Because of the necessity of completing the grind during one passage (open circuit) of the ore through the mill, it was built with a large length-diameter ratio. The tube mill is still largely used in South Africa and to some extent in North America for fine grinding generally following some other primary mills.
Tube mills are usually supported on hollow trunnions, the feed entering through a feed scoop at one end and discharging through the other. Drive is by a large gear fitted over the mill shell. Various types of liners are used, as in ball mills.
All rotary mills must be fitted with some kind of replaceable liners. Chrome steel, manganese steel, and white iron are generally used. Shapes designed to give a corrugated or shiplap surface to the interior of the mill are often used to prevent slippage of the ball load. Pocket liners arealso common. These liners have pockets in which the balls become lodged to form the wearing surface.
Rubber liners have been tried experimentally but have not been adopted by the industry. According to Taggart, no fully satisfactory method of holding the liners in place was worked out, utility was limited to fine feeds and small balls, mill capacity was reduced, and while a slightly higher grinding efficiency was shown in comparative tests with steel liners, there was no indication that possible increased wear for rubber would offset its far greater cost.Silex liners with flint pebbles for grinding media are sometimes used where iron contamination must be avoided.
The grinding that takes place in mills of this type is usually ascribed to two actions, impact and attrition, although some authors do not believe that a sharp line of demarcation can be drawn between the two actions.
In rod mills there is line contact between the rods, there is less grinding by impact, and the action resembles that of crushing rolls. As a result, a rod-mill product usually contains a greater percentage near the limiting size with less extreme fines than ball or tube mills.
In selecting the correct grinding media it is important that the rods or balls supplied be large enough to break the largest particles of ore in the feed, and as already discussed, a seasoned load composed of balls of all sizes, which is the condition found in a mill that has been operating for some time, gives better grinding efficiency than a new charge.
The volume of the charge is limited to a maximum of about 50 per cent of the mill volume. If the charge is too large, its center of gravity shifts too near the axis of the mill and the power input falls.
The speed of the mill is limited by what is known as the critical speed. This is the speed at which (assuming no slippage) the charge starts to cling to the liners, or to centrifuge. It is given by the formula.
The percentage of solids in the pulp is usually maintained at 60 to 75 per cent, the principle being to keep the volume percentage of solids as high as possible without loss of mobility of the charge. The correct proportion of water present will depend on the kind of ore being handled, slimy ores in general requiring a higher dilution than ores that have a low slime content.
The size of mill required for a specific grinding problem will depend on the character and size of the feed and the product desired and whether open- or closed-circuit grinding is desired. An accurate estimate of capacity can be made only by an engineer familiar with the proper evaluation of the factors involved.
For rough estimating purposes Table 6 gives approximate capacities grinding to 48 and 100 mesh for several size mills. Connected horsepower is also shown. These figures are for what would normally be considered average siliceous ore and for nominal circulating loads of 2 or 3 to 1.
These capacities may be reduced by as much as 50 per cent in the case of a hard, tough ore which is highly resistant to grinding, and for this reason considerable thought has in recent years been given to methods for determining the relative grindability of different ores and to correlating laboratory figures with plant performance. F. C. Bond has published comprehensive grindability data based on work carried out by the Allis-Chalmers Manufacturing Co. and grindability tests are a regular part of the testing procedure of the Dorr Company at the Westport, Conn., laboratories.
When the tube mill was first introduced, grinding was done in open circuit; i.e., the ore was ground to pass the limiting screen size by one passage through the mill. It was found, however, that if sufficient time of contact between the ore and grinding media were provided to ensure that no unground particles (or oversize) discharged from the mill, an excessive amount of fines were produced. This meant that the ore was ground much finer than necessary and mill capacity was correspondingly reduced.
The difficulty was overcome by placing a classifier in the circuit to separate out oversize from the mill discharge and return it to the mill feed. In closed-circuit grinding no attempt is made to finish the grind in one passage through the mill, but every effort is made to remove finished material as soon as it is released, thus reducing over-grinding and preventing the fines from hindering the grinding action on yet unreduced particles. In this way the tonnage that a given mill will grind is much greater than it is possible to grind in open circuit.
By using wide classifiers with high raking capacity, circulating-load ratios are now being carried to 4:1 or higher. The direct result of the increased capacity is reduced power, liner, and grinding media consumption per ton of finished ore.
There is, of course, a limit as to how large a circulating load can be carried in practice. While capacity continues apparently to improve, though at a decreased rate, it becomes increasingly difficult to move the growing volume of material through the system.
There is some controversy in the literature as to the definition of ratio ofcirculating load. The term used by most millmen is the ratio of sand tonnage returned to the mill to the tons of original feed.
If the mill-classifier circuit is fed into the classifier instead of into the mill, the sand contains oversize from the original feed as well as oversize from mill discharge, and thus the definition is not entirely accurate. The ratio of circulating load can be calculated from screen analyses by using the following formulas:
Circulating-load ratio = d o/s d where d = cumulative percentage 0n any mesh in the mill discharge o = cumulative percentage on same mesh in the classifier overflow s = cumulative percentage on same mesh in the classifier sand
There are many types of flow sheets in use today. The tendency in new mills is to crush relatively fine ( to in.). Single-stage ball mills in closed circuit with classifiers are used for grinds coarser than 48 mesh, but when a finer product is desired, two stages of ball mills in closed circuit with classifiers is usual. Efficiency must necessarily be sacrificed to some extent in small mills by capital requirements, and even greater reduction ratios are justified in a single-stage grinding unit.
With the large classifiers used for high circulating loads it is quite often necessary to use some kind of auxiliary device to complete the closed circuit. A large motor-driven scoop lifting the mill discharge to the classifier has been successful.
Stamp mills were built to parallel the operation of a mortar and pestle, working continuously and on a large scale. Ore is fed into a mortar and is crushed by the dropping of the stamp on a die at the bottom of the mortar. The crushed ore discharges through a screen in the side of the mortar.
The shoe that forms the wearing surface on the dropping stamp is attached to a steel stem and is replaceable. The stem is lifted by a cam operating against a tappet which is bolted to the stem. A common camshaft activates usually five stamps in a battery.
Milling was done in unique, crude wooden stamp mills developed by the ingenious Antioquenan miner. Made entirely of hand-hewn hardwrnod (except for cast-iron shoes, several bolts, and a few nails) these molinos Antioquenos have a stamp duty of approximately 0.4 tons per 24 hr. They are powered by overshot water wheels, 18 to 24 ft. in diameter, mounted directly on the 18- to 24-in. wooden camshaft of the mill. Up to 56 drops per minute can be obtained with a water-wheel speed of 14 r.p.m. The stamps, 6 by 7 in. by 14 ft. in dimensions, weigh 450 to 500 lb. including the cast-iron shoe. The mills are usually built with three stamps to the mortar box and as many as three sets (nine stamps) per mill. Battery-box screens are usually made of tin from 5-gal. gasoline cans perforated with a small nail. Stamp guides, cams, and the hardwood camshaft bearings are lubricated with beef tallow.
The stamp mill was originally devised as a combination grinding and amalgamating device before the days of cyanidation. Its use continued with theintroduction of the cyanide process, where it was well suited to the comparatively coarse crushing used, the distribution of the ground pulp over amalgamation plates, and the steps of separate cyanidation of sand and slimes that followed. As the all-sliming method became more generally adopted, however, with the need for fine grinding in ball mills and preferably in cyanide solution, the stamp mill tended either to be used as a secondary crusher or to be replaced altogether by dry-crushing equipment.
These two types of mill are practically obsolete. In these mills rollers driven from a central gear-driven spindle revolve around a pan. In the former the rolls crush against a ring in the bottom of the pan, and in the latter centrifugal force holds the rollers against the ring at the side of the pan. Chilean mills were used at the Golden Cycle up to a few years ago for grinding roasted ore.
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ten ways to improve the grinding efficiency of your ball mill
There are a lot of problems that most mineral processing plant meet when operating theball mill, such as low grinding efficiency, low processing capacity, high energy consumption, unstable product fineness of the ball mill. So how to effectively improve the grinding efficiency of ball mill is an important issue for the mineral processing plants. Here are ten ways to improve the grinding efficiency of ball mill.
The complexity of grindability is determined by ore hardness, toughness, dissociation and structural defects. Small grindability, the ore is easier to grind, the wear of lining plate and steel ball is lower, and the energy consumption is also lower.Therefore, the property of raw ore directly affects the productivity of the ball mill.
The larger feed size, the more work that the ball mill needs to do on the ore. To achieve the specified grinding fineness, the workload of ball mill will be increased inevitably, and then, the energy consumption and power consumption will be increased accordingly.
In order to reduce the feed size of ore, the particle size of crushing product must be small, that is, "morecrushingand less grinding". Moreover,the efficiency of crushing is obviously higher than that of grinding, and the energy consumption of crushing is low, which is about 12%~25% of the grinding.
In the case of a certain milling speed, larger filling rate, bigger grinding area, and stronger grinding effect. However, the power consumption is also large, and it is easy to change the motion state of the steel ball if the filling rate is too high, then the impact effect on large particle materials is reduced. Conversely,the smaller filling rate, the weaker grinding effect.
For many mineral processing plants, the filling rate is generally at 45%~50%. But the condition of mineral processing plants is different, just copying othersfilling rate cannot obtain the ideal grinding effect. The specific value should be decided by the mineral processing test.
Since the contact between steel ball in the ball mill and ore is point-to-point. If the diameter of steel ball is too large, the crushing force is also large, so the ore is crushed along the direction of the penetrating force, not the interface among different minerals. This crushing is not an option, which doesnt meet the purpose of grinding.
In addition, in the case of the same filling rate, too large diameter of the steel ball results in less steel balls, low crushing probability, serious over-crushing phenomenon and uneven product particle size. But if the steel ball is too small, the crushing force on the ore is small, and the grinding efficiency is low according. Therefore, it is very important for grinding efficiency to adopting accurate size of the steel ball and its proportion.
Obviously,the grinding action between steel ball and ore causes the wear of steel balls, which can change the proportion of steel balls, affect the grinding process and cause the fineness change of grinding products. Therefore, only by adopting reasonable steel ball supplementation system can the ball mill keep stable operation.
Low grinding density, fast pulp flow,the material is not easy to stick around the steel ball,so the impact and grinding effect of steel ball on materials is weak,theparticle size of ore discharging is unqualified, and the ideal grinding efficiency cannot be achieved;
High grinding density, the material is easy to stick around the steel ball, so the impact and grinding effect of steel ball on materials is good, but the pulp flows slow, which is not conducive to improve the processing capacity of the ball mill.
There are some measures taken to control the grinding density. For example, control the ore feed of the ball mill, control the water supply of the ball mill, adjust the classifying effect, and control the particle size composition and moisture of the sand return.
In actual production, the grinding process can be optimized according to the ore properties, such asthe disseminatedgrain size ofuseful minerals, monomer dissociation degree, the disseminated grain size of gangue minerals. For example, adopting pre-discarding tailings, pre-enrichment, stage grinding, pre-classification to optimize the grinding process, which not only reduces the amount of grinding, but also recovers the useful minerals as soon as possible.
Classifying efficiency plays an important role in grinding efficiency. High classifying efficiency means that those qualified grains can be discharged timely and efficiently,while low classifying efficiency means that most qualified grains are not discharged and sent to the ball mill for re-grinding, which is easy to cause over-grinding and thus affecting the separating effect.
Sand-returning ratio is the ratio between the amount of sand return of ball mill and the feeding capacity of raw ore, which can directly affect the productivity of the ball mill. One way to improve the sand-returning ratio is to increase the feeding capacity of raw ore, another way is to reduce the shaft height of the spiral classifier.
But there is also a limited value in the improvement of sand-returning ratio. When it is increased to a certain value, the increase amplitude of the productivity is very small,the total feeding capacity of the ball mill is very close to the maximum processing capacity of the ball mill, that may cause overage grind, so the sand-returning ratio should not be too large.
There are many variable parameters during the grinding operation, and one change will inevitably lead to the change of many factors one after another. Generally, the manual operation control may cause unstable production, while the automatic control can keep the grinding and classifying in a stable and suitable state, thus improving the grinding efficiency.
There are many factors affect the grinding efficiency in the grinding process. Many factors can be judged as qualitative analysis, which are difficult to make quantitative analysis. therefore, the ball mill operator must do a comprehensive analysis according to the actual production situation and the result of the qualitative analysis,thus drawing the reasonable parameters to decrease the production cost, saving energy and reduce the consumption.
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ball mill | ball mills | wet & dry grinding | dove
DOVE Ball Mills are supplied in a wide variety of capacities and specifications. DOVE small Ball Mills designed for laboratories ball milling process are supplied in 4 models, capacity range of (200g/h-1000 g/h). For small to large scale operations, DOVE Ball Mills are supplied in 17 models, capacity range of (0.3 TPH 80 TPH).
With over 50 years experience in Grinding Mill Machine fabrication, DOVE Ball Mills as critical component of DOVE Crushing plants are designed with highest quality of material for long life and minimum maintenance, to grind ores to 35 mesh or finer.
DOVE Grinding Mills are supplied in a wide range of capacities and specifications, for reliable and effective grinding, size reduction applications and for diverse applications of either dry or wet ore.
DOVE Ball Mills have extended history in the Mining and Mineral Processing Industry, Construction, Solid Waste Processing, Food Processing Industry, Chemical and Biochemical Industry, for Pyrotechnics and Ceramics.
DOVE Ball Mills are designed to operate with various types of grinding media, including Ball Mills Balls. DOVE supply Steel Balls in Various sizes and specifications. Cast Iron steel Balls, Forged grinding steel balls, High Chrome cast steel bars, with hardness of 60-68 HRC. We also supply Grinding Cylpebs with surface hard ness of 60-68 HRC, and grinding Rod with surface hardness of 55-60 HRC.
DOVE Ball Mills are made of high grade cast and carbon steel for extra strength, long and trouble-free operations. The inner lining plate designed with high manganese steel for long life and minimum wear off.
DOVE Ball Mill can be integrated in a Complete Plant designed by DOVE Engineering Services, provided for our Clients application and supplied with all components of the plant for efficient processing, smooth operation and efficient integration with the balance of the Processing Plant.
DOVE Ball mills, also known as Grinding mill, Mining mill, Pebble mill, Ball & Pebble mill, is an important machinery in the mining and various other industries, which would require grinding different material.
They are highly efficient Grinding mill machines, designed for grinding applications, where fine material is required. DOVE Ball Mills are used in supplied and applicable for wet and dry grinding applications within the following branches of industries:
DOVE ball mills is a rotating horizontal cylinder that tumbles the material to grind with a certain media. The standard media that we use in our ball milling process are the steel grinding balls, however depending on the specific application, we can configure the grinding mill with different media.
DOVE supplies various types and sizes of Ball Mill Balls, including; Cast Iron steel Balls, Forged grinding steel balls, High Chrome cast steel bars, with surface hardness of 60-68 HRC. DOVE Ball Mills achieves size reduction by impact and attrition. When the cylinder rotates, the balls are dragged to almost the top of the shell, and from there, they fall unto the material, which lead to the material breaking due to the impact.
DOVE Ball Mills are used in hard rock mineral processing plants as an ore-dressing step to grind the rocks into fine powder size, liberating the mineral particles from the rocks. This will ensure that the ore is well prepared for the next stage of processing and optimize the recovery of the minerals.
DOVE ball mill is integrated and used in DOVE Portable and Semi-Stationary Hard Rock plants (Hard Rock processing plants) to efficiently grind the ore from primary deposit until the liberation size of valuable minerals is reached. DOVE ball mill is the key grinding equipment after material is crushed. It is used to grind and blend bulk material into powder form using different sized balls. The working principle is simple, impact and attrition size reduction take place as the ball drops from near the top of the rotating hollow cylindrical shell of the Ball Mill. The output materials will be feed to the processing and recovery machines.
DOVE Ball Mills are deigned for either wet or dry grinding of materials, in various models, and in accordance to the processing and the crushing plant design, to cater to the liberation size of the minerals and the hardness of the ore.
DOVE supplies two different kinds of ball mills Grate type, and Overfall type. The difference between the two type is according to their ways of discharging material, and the plant flow design specifications.
The Grinding Balls will grind the material into powder size of 20 to 75 micron. In mining operations, this will allow for the liberation of gold and other precious metals that are hosted by the rocks. Many types of grinding media are suitable for use in a ball mill, each material having its own specific properties, specification and advantages.
Media Size: The grinding media particles should be substantially larger than the largest pieces of final material after grinding. The smaller the media particles, the smaller the particle size of the final product.
Composition: Each ball mill application has different requirements. Some of these requirements are relates to the grinding media being in the finished product, while others are based on how the media will react with the material being milled. Therefor, grinding media selection plays major factor on the final milled product.
Contamination: In certain grinding mill process, low contamination is important, the grinding media may be selected for ease of separation from the finished product, for example steel dust produced from steel balls can be magnetically separated from non-ferrous products. An alternative to separation is to use media of the same material as the product being milled.
Corrosive:Certain type of media, such as steel balls, may react with corrosive materials. For this reason, stainless steel balls, or ceramic balls, and flint grinding media may each be used when corrosive substances are present during grinding.
mining dasan group
Chrome ore deposits are mined by both underground and surface techniques. most chrome ore must be processed by the chrome ore processing plants. the main chrome ore beneficiation method is gravity separation. so the mainly used chrome ore concentrating equipment are ore washbox (sometimes it is called jigger), concentrating table, spiral classifiers, etc.
1. Large raw chrome ore for primary crushing is fed into the jaw crusher by Plate feeder and are reduced to 8 inches or smaller. After first crushing, the material will be transferred to cone crusher by belt conveyor for secondary crushing; the crushed chrome ore stone will then transferred to vibrating screen for classifying. After classifying, the parts whose size below the mesh size will be transferred away as final products, while the other parts will return to cone crusher, thus forming a closed circuit. Size of final products can be combined and graded according to your specific requirement.
3. Screened products are transported to the jig for rough separation and to three concentrating tables for fine separation. Then, tailings are delivered into the jig in the next stage for screening 4 times like this. All tailings int he concentrating table are sent to the tailings reservoir after tailings dry stacking.