According to different grinding media and grinding materials, the mill can be divided into ball mill, column mill, rod mill, tube mill, autogenous mill, rotary mill, vertical mill, multi-layer vertical millVertical roller mill, disc mill, DMC mill, etc.
According to different grinding media and grinding materials, the mill can be divided into ball mill, column mill, rod mill, tube mill, autogenous mill, rotary mill, vertical mill, multi-layer vertical millVertical roller mill, disc mill, DMC mill, etc.Widely used in ceramic industry productionIntermittent ball millThe grinding effect of wet production can be divided into two parts, one is the grinding effect between grinding bodies and between grinding bodies and cylinders, and the other is the impact effect of grinding bodies when falling. In order to improve the grinding efficiency, we should start from these two aspects.The technology and process of "more crushing and less grinding" of metal ores has been a topic for many years. Reducing the particle size of the ball mill and adding a pre grinding or ultra-fine crushing process in front of the ball mill are important technological innovations for energy conservation and consumption reduction of mining enterprises.The research on grinding process of mill isMineral processing engineeringOne of the key points in technology.Crushing and grinding process is to squeeze, roll, impact and grind the ore by using energy of the millUseful mineralThe monomer cleavage (separation) is conducive to the sorting process in the next stage.[1]
Scope of use
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Suitable for crushing baritecalcite、Potash feldspar、talc, marble, limestone, gypsumquartz、Activated clay, activated carbonBentonite, aged soil, glass, manganese ore, titanium ore, chrome ore, slag, etcMohs hardnessNon flammable and explosive materials with a humidity of less than 6% and no more than Grade 7: high fine milling processing of more than 280 materials in mineral, chemical, building materials and other industries, and the particle size of finished products can be adjusted arbitrarily within the range of 80-325 meshes.[2]
type
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length
(1) When the length diameter ratio of short grinder is below 2, it is called short grinder, or ball grinder.General single bin is used for rough grinding or primary grinding, and 2-3 ball mills can also be used in series.
(2) When the length diameter ratio of medium length mill is about 3, it is a medium length mill
(3) When the length diameter ratio of the long grinder is more than 4, it is called a long grinder or a tube grinder.Medium long mill and long mill are generally divided into 2-4 bins, which are used more in cement plants.
Grinding medium
(1) Ball mill.The grinding medium loaded into the mill is mainly steel ball or steel segment.This type of mill is most commonly used.
（2）Rod mill。A steel bar with a diameter of 50~100mm is loaded into the mill as the grinding medium.
(3) Baseball mill.This kind of mill usually has 2~4 bins. Cylindrical steel bars are loaded into the first bin as the grinding medium, and steel balls or steel sections are loaded into the subsequent bins.
The length diameter ratio of the ball mill should be about 5. The ratio of the length of the rod bin to the effective diameter of the mill should be between 1.2 and 1.5. The length of the rod should be about 100 mm shorter than the rod bin to facilitate the parallel arrangement of the steel rods and prevent cross and confusion.
(4) Gravel ball mill.The grinding medium loaded into the mill is gravel, pebble, porcelain ball, etc.Use granite and porcelain as lining plate.For white or colored cement and ceramic production.
Unloading mode
(1) Tail unloading ball mill.The material to be ground is fed from one end of the mill and discharged from the other end, which is called tail unloading ball mill.
(2) Intermediate discharge ball mill.The materials to be ground are fed from both ends of the mill and discharged from the middle of the mill barrel, which is called the intermediate discharge ball mill.This type of mill is equivalent to two ball mills used in parallel, so the equipment is compact and the process is simplified.
(3) Tail unloading ball mill.According to its layout mode, there are many types of grid layout, overflow layout, peripheral layout and wind layout.
Transmission mode
（1）Center drive ball millThe motor drives the hollow shaft at the discharge end of the mill through the reducer to drive the mill to rotate.The outlet shaft of the reducer is in a straight line with the center line of the mill.
(2) The motor of the edge drive ball mill drives the big gear fixed on the barrel at the discharge end through the reducer to drive the barrel of the mill to rotate.
Other classifications
According to process operation, it can be divided intoDry ball millWet ball mill, intermittent discharge ball mill and continuous discharge ball mill.Compared with intermittent discharge ball mill, continuous discharge ball mill has higher output, less power consumption per unit weight of product, higher degree of mechanization and fewer operators.However, the capital construction investment cost is large, and the operation and maintenance are complex.Intermittent ball millIt is seldom used and is often used as laboratory test mill.[2]
advantage
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The mill has the advantages of small floor area, 99% pass rate of finished product particle size, balanced host drive, low noise, simple installation and maintenance, reliable operation, multistage separation and dust removal, and no pollution.It is suitable for dry superfine powder processing of mineral materials. It is an ideal equipment in the grinding industry, especially for small enterprises.
Horizontal ball
Horizontal ball millyesSilicate products，New building materials, refractory, fertilizer, black and non-ferrous metals, quartz sand, glass ceramics and other production industries for dry or wet grinding of key equipment.Working principle: this machine is a horizontal cylindrical rotating device, driven by outer gear, sprocket or belt, with two compartmentsLattice ball mill。The materials enter the first chamber of the ball mill through the feeding hollow shaft of the feeding machine spirally and evenly. There are three kinds of ball mediums of different specifications inside. The rotation of the cylinder produces centrifugal force to bring the ball mediums to a certain height and then fall down, causing heavy impact and grinding on the materials.After coarse grinding in the first bin, the materials enter the second bin through a single-layer partition board. The bin is equipped with four different specifications of ball media to further grind the materials.The powdery material is discharged through the screen fence at the discharge port and enters the vibrating screen for grading to complete the grinding operation.Structural features: The machine is composed of feeder, discharging part, rotary part, transmission part, grading part and other main parts.The hollow shaft is made of cast steel, and the lining can be made according to the user's requirements. The equipment operates stably and reliably.
Silica ball type
The mill is the key equipment for crushing materials after they are crushed.Ball mills are widely used in cement,silicateProducts, new building materials, refractory materials, fertilizer, black and non-ferrous metal beneficiation, glass ceramics and other production industries, dry or wet grinding of various ores and other grindable materials.The machine consists of feeding part, discharging part, rotary part and transmission part（Reducer, small transmission gear, motor, electronic control).The hollow shaft is made of cast steel, and the lining can be replaced. The rotary gear is processed by casting hobbing. The cylinder body is inlaid with wear-resistant lining plate, which has good wear resistance.The machine operates stably and reliably.
Columnar
Column mill series products are used for limestone milling in power plants, superfine crushing of metal ores and iron ores, cement slag pre grinding, non-metallic gypsum grinding, and phosphorus ore grinding.
1. Column mill - working principle of Shenxiang column mill The Shenxiang column mill adopts the rolling grinding principle of continuous repeated medium pressure, with simple and scientific structure.The upper part of the column mill drives the main shaft to rotate, so that the roller rotates in the annular conical lining (the gap between the roller and the lining is adjustable and does not contact). After the materials are fed from the upper part, the self weight and the upper pushing action form a material layer between the roller and the lining plate. The material layer is crushed by the roller, and the powder is discharged from the lower part of the column mill automatically.Since the roller only rotates regularly, the material layer force mainly comes from the extrusion force and the pressure given by the elastic device, while the roller only rotates regularly, thus avoiding the loss and wear caused by the collision between the roller and the lining plate. Therefore, the energy saving and consumption reduction effect of the Shenxiang column mill is very obvious.
2. Column mill - the structure of Shenxiang column mill 1) The gap between rollers and liners can be adjusted according to the grain size requirements of discharged materials.2) The discharging device can adjust the residence time in the material mill to control the discharging particle size.3) The external spring is the source of extrusion force, which can be changed by adjustment.
3. Column mill - compared with other grinding equipment, Shenxiang column mill has the following characteristics: 1) large range, low production cost;2) The consumption of vulnerable parts is very low, which can reduce the production cost and iron pollution of materials with special requirements (iron pollution can be reduced to 2/100000) 3) The fineness can be adjusted, and the material size range of products can be strictly controlled;4) Small size, simple and convenient installation, which can save civil engineering investment;5) Low noise, less dust, good environmental protection effect;6) Good mechanical performance, simple operation and convenient maintenance;
4. Column mill - main technical parameters of Shenxiang column mill (taking magnetite ore as an example) Column mill - effect of Shenxiang column mill on iron ore process ① As a new type of ultra-fine crushing (coarse grinding) equipment, Shenxiang column mill has large single output, high crushing efficiency and convenient product particle size adjustment.② . Column mill - Shenxiang column mill has a large crushing ratio. The ore after rough grinding by Shenxiang column mill is less than 5mm, and the material has basically become powdery;The particle size distribution of the material from Shenxiang column mill is reasonable, the ore is fully dissociated, and the waste disposal rate is high, which can significantly reduce the proportion of the material into the ball mill and the particle size of the ore feed, and improve the production capacity of the system;③ , Shenxiang column mill and other main and auxiliary equipment (ball millPowder concentrator、Hoist), the best grinding effect of the whole system can be achieved.④ Wearing parts have good wear resistance.Wearing parts are made of highwear-resisting alloy steelTherefore, it has good wear resistance and low steel consumption.⑤ Convenient operation and maintenance.Compared with various large vertical mills abroad and other domestic grinding equipment, the Shenxiang column mill is simple to operate, high in operation rate and convenient in maintenance.
5. In conclusion, the application of the column mill - Shenxiang column mill in the iron ore industry has a broad prospect. From the perspective of investment, power consumption, medium wear, material moisture adaptability, etc., it is the most ideal pre grinding equipment at the current technical level and process conditions.It is effective for the system to increase production and save energy, reduce production costs and improve the quality of concentrate, create greater profit space for enterprises, and improve the resource, economic and social benefits of China's metal mining development and utilization as a whole.
DMC type
DMC mill is a new type of mill with spindle rotating, multi-layer grinding and centralized powder selection.DMC mill only solves the revolution (horsepower) of grinding roll in one working mode during operation.DMC mill and Raymond mill have different working methods: Raymond mill's working hours mainly depend on grinding ring and grinding roller to squeeze materials (shearing:Grinding rollWhen it is in cross line contact with the grinding ring), it is used to feed materials (commonly known as the blade device to feed materials between the grinding roller and the grinding ring, so that the friction of materials entering the middle of the grinding roller and the grinding ring increases greatly, causing large wear loss of wear parts)DMC mill and ball mill work in different ways. During ball mill work, the grinding body (steel ball or steel section) is mainly in point contact. During operation, the equipment itself and materials need power to drive together, so the power consumption is also large.The DMC mill is also different from the vertical mill. When the vertical mill works, the power drives the grinding plate and materials, and the grinding roller rotates passively. This kind of bearing is large and the power required is also large.DMC mill is a new type of mill which combines the advantages and disadvantages of the above mills.[1]
EM73 Vertical grinder
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Process Flow Diagram of Vertical Grinder
Vertical grinderThe system is mainly composed of pre grinding bin, belt scale, vertical grinder, post grinding bin, etc. (Figure 1).Coke particles (<6 mm) stored in the feed bin of the mill are measured from the raw material chute through the belt scale, and then enter the mill through the rotary discharge valve. They are fully dispersed and mixed and fall on the cover plate. Due to the centrifugal force, the materials to be ground are pushed to the grinding area of the grinding ball, and the ground materials are discharged around the grinding parts through the negative pressure of the fan,The powder is pumped to the hollow part of the grinding chamber to the separator. Under the action of centrifugal force and gravity, the separator will separate the particles exceeding the size, and these particles will return to the grinding area through the grinding cone.Only the materials that meet the grinding fineness requirements can be discharged into the dust collector through the immersed tube and transported to the powder batching bin through the screw.[3]
Process Flow Diagram of Vertical Grinder
Structure and grinding principle of vertical grinder
The cylinder of vertical grinder is cylindrical, the upper part is conical, and the top of the cone is equipped with a dynamic separator. The bottom of the grinder is equipped with a drive device, a gearbox and a hydraulic device. There are grinding elements, pressing rings, mill yokes, etc. inside. The grinding elements include the lower grinding ring, grinding ball, and upper grinding ring. The grinding elements are metal castings with high wear resistance. The grinding ball is hollow spherical, with an outer diameter of 800 mmDifferent sizes, such as 900mm and 1000mm, are equipped with grinding balls of different sizes according to the system capacity. The grinder is generally equipped with 5 grinding balls.The pressing ring is used to fix the upper grinding ring. The pressing ring can move vertically and freely in the machine body, which can prevent foreign matters from blocking and damaging the grinding element.The mill yoke is the connecting piece between the lower grinding ring and the transmission device.The grinder has an access door in the middle.In addition, the grinder is also equipped with a hydraulic oil supply system and a gearbox oil supply system.The cylinder body of vertical grinder is a closed unit, in which grinding, separation and conveying can be carried out simultaneously. The grinder operates continuously.
The grinding pressure comes from the hydraulic device installed in the grinder. The tension rope of the hydraulic cylinder transmits the traction force to the spring tension bracket in the grinder. The spring tension bracket distributes the grinding pressure evenly to the pressure ring, upper and lower grinding rings and grinding balls, making the upper and lower grinding rings and grinding balls rotate. Then the particles in the grinder are ground into powder,The grinding fineness can be adjusted by adjusting the rotor speed of the dynamic separator during operation.When foreign matters (such as stones, iron blocks, etc.) enter the grinder, they will be automatically separated during the grinding process and discharged into the discharge valve for collection.[3]
Operating Procedures
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1. Operators and apprentices can operate independently only after they have received technical safety education and passed the actual assessment.Personnel who are not involved in this process are not allowed to use them without the consent of the leader.
2. Before operation, the machine tool must be checked to see if it is running normally. If any problem is found, it should be repaired in time before operation.
3. After the machine tool is started, it is forbidden to touch the external and internal gears with fingers to prevent safety accidents.
4. After the work is completed, the power must be turned off and wiped clean, and always keep clean.[3]
