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   1. The ball mill bearing heats up and checks for lack of oil.
   2, the main bearing and pinion shaft bearing with grease lubrication, reducer and oil lubrication.
   3. If there is no shortage of oil, check the concentricity of each part and check the main unit and the transmission part separately. The large bearing seat is not concentric with the hollow shaft, causing the hollow shaft to frictionally generate heat with the bearing gland. The pinion shaft of the drive is not concentric with the bearing housing, causing friction between the drive shaft and the bearing gland. If the reducer and the pinion shaft are not concentric, and the reducer and the motor are not concentric, the bearing will be overloaded and heated. When the hollow shaft is not completely different from the large bearing seat, it may cause difficulty in starting, power consumption during operation, and heat generation of the motor.
   4. Therefore, it is very important to ensure the concentricity of each part during installation.
Ball mill related technical operation guide
What is the grinding process? What are the common grinding processes?
The grinding process refers to the path (technical process) through which the slurry flows during the grinding operation. Grinding can be divided into open-circuit grinding and closed-circuit grinding. Open-grinding is the material discharged from the grinding machine and sent directly to the next operation: while the closed-mill grinding material is discharged into the classifier, the fine particles will be Qualified products are dispensed in time and sent to the next operation, while the coarse grade is returned to the mill for re-grinding. This not only improves the processing capacity of the mill, but also avoids over-grinding and reduces muddy phenomenon. Therefore, the closed-circuit process of the combination of the mill and the grading operation is widely used in the selection plant.
Practice has proved that: using one or two stages of grinding process, the ore can be economically ground to the required size of the sorting, without having to use more grinding sections, more than two stages are usually determined by the requirements of the stage selection. .
The number of segments grinding to conduct a comprehensive technical and economic comparison of the scale beneficiation plant, the fineness of the final product required by the nature of the ore and other factors, in order to ultimately determine. Obviously, the more segments, the more complex the process.
The purpose of grading and the grading equipment commonly used in the concentrator?
As mentioned above, when the ore is ground, it is necessary to promptly separate the ore particles that have met the fineness requirements. This not only improves the processing capacity of the mill, but also avoids over-grinding. However, it is very difficult to carry out particle size classification in the mill. This task is accomplished by a classifier. The wet grading mainly utilizes the difference of the sedimentation speed of the ore particles in the water, and separates the ore particles of different particle sizes and different densities, and the qualified grit is sent from the classifier to the sorting operation. The coarse fraction is regrind as a grit backing mill of the classifier. It can be seen that grading plays an important role in grinding.
The mechanical classifiers that form closed circuits with the grinding machine include a jaw classifier, a float classifier, a spiral classifier and a hydrocyclone. A spiral classifier or a hydrocyclone is widely used at present. In recent years, many factories have adopted a fine screen with high classification efficiency and a grinding machine to form a closed circuit.
What should be done in the operation when the grinding machine “swells�
First of all, we must analyze the change of ore properties, give the amount of ore, water supply, sand return, and overflow particle size normal, find out the reason, "the right medicine." In operation, the following measures can generally be taken:
(1) Reduce the amount of ore fed to the mine or stop feeding to the mine in a short time. This can reduce the working load of the mill and reduce the amount of minerals passed by the mill.
(2) Adjust the amount of water used. Grinding concentration must be strictly controlled. Too large or too small will have adverse effects. When the concentration is too high, the flow rate of the slurry becomes slower, and the impact of the grinding medium becomes weak. For the overflow type ball mill , the size of the ore discharge becomes coarse, and the lattice ball mill may appear to be "bloating".
(3) Reasonably add grinding media. If the loading of the medium in the grinding machine is insufficient, the grinding medium of an increased size should be appropriately supplemented.
What are the phenomena and causes of the "flattening" of the grinding machine?
When the grinding machine “swellsâ€, the following phenomena generally occur:
   (1) The main motor ammeter indicates that the current is decreasing;
   (2) The grinding machine discharges a large amount of ore and the slurry is poured out;
   (3) The “running rough†phenomenon of the classifier overflow is serious, and the amount of sand returning is obviously increased;
   (4) The operation of the grinding machine is dull, and the impact sound of the steel ball is hardly heard.
   The phenomenon of "swelling belly" is the result of the imbalance of the working of the mill. Because of certain specifications and types of grinding machines, under certain grinding conditions, only a certain passing ability is allowed. When the nature of the ore is changed, or the amount of ore is increased or the coarse grain is added to increase the ratio of returning sand, because it exceeds the passing ability of the grinding machine itself, it will be “digestedâ€, that is, “expansion†occurs. The belly phenomenon. Then the improper operation will also cause the "flat" of the grinding machine. For example, improper use of grinding water has a direct impact on the grinding concentration, while excessive grinding concentration may cause "blowing". In addition, the total amount of the grinding media or the unreasonable ratio of the ball diameter can also cause "bloat". [next]
What is the operating rate of the grinding machine? How to calculate?
   The operating rate of the mill can also be referred to as the operating rate, which is the percentage of the actual operating time of the mill to the calendar time. This is an indicator of the actual operation of the mill. Its calculation method is:
   Grinding machine operating rate = grinding machine × actual operating hours 磨 (grinding machine × calendar hours) × 100%
What is the critical speed of the mill? How to calculate?
   When the grinding machine is at different speeds, the grinding medium (such as steel ball) moves in the grinding machine according to the rotation speed of the grinding machine, which can be divided into three conditions.
Due to the different rotation speed of the grinding machine, the magnitude of the centrifugal force of the grinding medium in the cylinder is also different, and the centrifugal force increases with the increase of the rotation speed of the cylinder. When the rotational speed of the grinding machine is increased to a certain value, the grinding medium of the outermost layer in the cylinder begins to produce "centrifugal operation", and the grinding machine rotation speed is called "critical speed".
   Some studies have pointed out that the friction between the steel ball and the cylinder and other factors are not considered in the above formula of the critical speed formula. Therefore, the critical speed data calculated according to the formula can often be exceeded in practice.
   As the ratio of sand return increases, the coarse grade content of the mill also increases, which also increases the amount of ore per unit time passing through the mill, which speeds up the discharge rate and shortens the ore grinding time, thus improving the qualified Granular productivity. At the same time, the re-grinding phenomenon is reduced due to the relative reduction of the fine-grained content in the ore-feeding, which is beneficial to improving the efficiency of the grinding technology. It can be seen that closed-circuit grinding is beneficial to increase the return-to-sand ratio. Practice has shown that increasing the sand return ratio within a certain range does not increase the power consumption, and even lowers in some cases.
   According to the results of the experimental research, the mathematical formula for the relationship between the productivity of the mill and the sand return ratio is:
Q 1 (C 2 +1)
—— = ——————————
Q 2 (C 1 +1)
What is the return sand ratio? How to calculate?
   In the closed-circuit grinding operation, the grader that returns to the grinding machine for re-grinding is called sand returning. The ratio of the amount of sand returned to the original ore amount of the mill is called the return sand ratio and can be expressed as a percentage. Its calculation formula is as follows:
         100(β-α)
   C = ————————%
— — θ
   Where C - return sand ratio, %;
   Α—the yield of a specified fraction in the ore discharge of the mill, %;
   Β——the yield of the above specified fraction in the overflow of the classifier, %;
   θ - the yield of the above specified fraction in the sand return of the classifier, %.
   After the ore discharge from the grinding machine, the sand returning from the classifier and the overflow sampling and analysis, and the values ​​of α, β and θ are obtained, the returning sand ratio can be calculated according to the above formula.
What are the main factors affecting the efficiency of grinding technology?
   The main factors affecting the efficiency of grinding technology are summarized as follows: [next]
   First, the impact of ore properties
   The composition and physical properties of the ore have a great influence on the efficiency of the grinding technology. For example, when the useful mineral in the ore is coarser in size and the structure is loose and brittle, it is easier to grind. When the useful mineral has a finer grain size, a dense structure, and a higher hardness, it is more difficult to grind. In general, the coarse-grain grade is easier in rough grinding, the faster the yield of the qualified particle size, and the finer the grinding. Because the fragile surface of the material decreases with the reduction of the particle size, that is, becomes more and more sturdy, the rate of producing the qualified particle size is slower. Therefore, the coarse grinding technology is more efficient than fine grinding.
   Second, the impact of equipment factors
   Equipment factors have a certain impact on the efficiency of grinding technology. For example, the overflow ball mill has a slower discharge rate, and the large density of the ore is not easily discharged, and it is easy to cause excessive pulverization. In addition, the classifier which constitutes a closed circuit with the grinding machine, when the classification efficiency is low, is easy to be pulverized, thereby reducing the efficiency of the grinding technology.
   Third, the impact of operational factors
   Operational factors undoubtedly affect the efficiency of grinding technology. For example, in closed-circuit grinding, when the ratio of returning sand is too large and exceeds the normal passing ability of the grinding machine, the phenomenon of “running rough†will appear in the grinding products. If the sand return ratio is too small, or there is no sand return, it is easy to cause over-grinding. If the load is too large, the phenomenon of “running rough†in the grinding products is serious, and if the load is insufficient, the crushing is severe. Therefore, it is required to give uniformity and stability to the ore during sanding. When the ore amount is given, the efficiency of the grinding technology will be improved.
   The grinding grain size of each section is determined to be unreasonable. It also affects the efficiency of grinding technology.
   Grinding concentration has a great influence on the efficiency of grinding technology. The grinding concentration of the country directly affects the grinding time. If the concentration is too large, the material flows slowly in the mill, and the grinding time increases, which is easy to be pulverized. In addition, in the high concentration of the slurry, the coarse particles are not easy to sink, and it is easy to flow away with the slurry, resulting in "running rough". If the concentration of the slurry is too thin, the material flow rate will increase. The time of grinding is shortened. There will also be “running roughâ€, and large-density ore particles will easily deposit on the bottom layer of the slurry, which will also cause over-grinding. Therefore, proper grinding concentration should be mastered during operation, which requires strict control of water consumption. Generally, the coarse grinding concentration is usually 75-85%, and the fine grinding concentration is generally 65-75%.
What is the basic principle of the grinding process?
   Grinding operations are carried out in a mill body with a grinding medium. After the grinding medium is brought to a certain height with the rotation of the cylinder, it falls due to the weight of the medium. Therefore, the ore contained in the cylinder is subjected to the impact of the medium; on the other hand, due to the revolution and rotation of the grinding medium in the cylinder along the axis of the cylinder, the grinding medium and the contact area with the cylinder are generated again. The ore is crushed and ground to remove the ore.
   Due to the friction between the steel ball and the cylinder, when the cylinder rotates, the steel ball is brought up and raised to a certain height. Due to the gravity of the steel ball itself, it finally falls along a certain orbit. The steel ball in the area (the steel ball is carried) is subjected to two kinds of forces: one is the force applied to the steel ball from the tangential direction when the cylinder rotates; the other is the opposite side to the diameter of the steel ball and the above The force of opposite force, which is caused by the downward sliding of the steel ball itself due to its own weight. Therefore, the above two forces will constitute a pair of couples for any one steel ball. And since the steel ball is squeezed between the cylinder and the adjacent steel ball, the force couple will cause the steel balls to have frictional resistances of different sizes from each other, so the steel balls of each layer will revolve with the axis of the cylinder. Movement (of course, the balls of each layer do not have a synchronous rate with the cylinder, and the revolution speed of each layer of steel balls is also different). In the area, the steel ball is thrown down from the top and bottom, so that the ore in the cylinder body has a strong impact crushing effect in the area. Due to the impact of the falling of the steel ball, the steel ball produces extremely strong and disorderly movements in the area. These include: (1) strong rolling of the steel ball above the dotted line; (2) rapid movement of the steel ball along the dotted line; (3) rapid movement of the steel ball below the dotted line with the mill barrel; (4) layers The mutual impact between the steel balls. It can be seen that the area is the place with the strongest grinding action. Most of the coarse ore particles are ground here. [next]
   It can be seen from the above that the ore is mainly ground in the mill barrel by the action of impact force, grinding and peeling force and pressing force.
What is the purpose of grinding? What is the relationship between it and the sorting operation?
   Grinding is the continuation of the crushing process and the last processing of the ore before sorting. The purpose of grinding is to achieve all or most of the useful components in the ore to separate the monomers. At the same time, we must try to avoid the phenomenon of "over-grinding". And can achieve the granularity required for the sorting operation, in order to create conditions for the sorting operation to effectively recover the useful ingredients in the ore.
   A lot of grinding work and sorting operations, sorting good and bad indicators (quality of concentrate and metal recovery), and depends largely on the quality of grinding minerals. If the fineness of the grinding product is insufficient and the mineral particles do not reach a sufficient monomer separation from each other, the selection index will not be too high. If the slime produced by grinding, no matter which kind of mineral processing method can not be effectively recycled. For example, a strong magnetic separator can effectively recover a particle size lower limit of 30 microns. Slime less than 30 microns is difficult to recycle. The lower limit of the particle size of the electrostatic concentrator can be effectively recovered. The lower limit of the particle size is 25 microns, and the less than 25 microns is the slime, which is difficult to recycle. For froth flotation, the lower limit of the effective recovery is 3 - 5 (10) microns. If a large amount of slime (ie, less than 3 - 5 (10) micron ore) is produced due to grinding, the flotation agent consumption will increase, the flotation process will lose selectivity, and the recovery rate and concentrate grade will be Affected, even in severe cases, it will make the flotation difficult to carry out normally.
   In addition, the grinding products are also required to meet the concentration required for the sorting operation. Various sorting operations have their appropriate concentration ranges, which are not suitable for too high or too low.
   Grinding operations also have a lot to do with the economic indicators of beneficiation. Grinding is one of the most power-consuming operations of the concentrator. Only crushing and grinding accounts for about 45-65% of the power consumption of the plant. At the same time, the grinding operation is also a large operation that consumes metal. According to statistics, when grinding a ton of ore, the total loss of grinding media (such as steel balls or steel bars) and liners is 0.4-3.0 kg. Therefore, in the entire ore dressing cost, grinding costs account for a large proportion.
It can be seen that improving grinding operations, improving the quality of its products, reducing grinding costs, and increasing the productivity of the grinding machine can not only improve concentrate quality and metal recovery rate. It is also important to reduce the total cost of dressing and increase the productivity of the concentrator.
Hydraulic classification
   Hydraulic suspension flow is mainly used for fine coal and slurry SimpleChoice sorting and removing pyrite sulfur coal, and effective separation size of 100 mesh limit oxidation of the coal. The utility model has the advantages of no moving parts, simple structure system, small ground occupation, large processing capacity, convenient operation and low production cost; but as an independent single sorting device, since the sorting precision is low, pure vermiculite cannot be obtained at the same time. And high quality and exquisite products. Therefore, the use of the water medium selector should consider the two-stage selection and joint process. The latter, such as the combined sulfur analyzer and flotation combined process, has been put into use in the Guanyintang Coal Preparation Plant in China.
What is granularity? What is the grade? What is a mesh?
   Particle size refers to the size of the ore particles and is generally expressed in terms of the maximum length of the ore particles.
   Usually the material is composed of ore particles of various sizes. In order to indicate the composition of the material particle size, it is often expressed as a percentage of several grades (or fractions). For example, in a certain material, the 1-3 mm fraction is 10%, that is, the maximum particle size of the material in this range is 3 mm and the minimum is 1 mm. This grade of material accounts for 10% of the total material.
   The mesh is the size of the mesh size indicating the standard sieve. In the Taylor standard sieve, the so-called mesh is the number of sieve holes in the length of 2.54 cm (1 inch), and is simply referred to as the mesh. For example, a 200-mesh sieve means that the sieve has a 200-year mesh per 2.54 cm length of screen, and the mesh size is 0. 074 mm (the fewer the mesh, the larger the mesh size). The fineness is -200 mesh, accounting for 70%, which means that the particle size content of less than 0. 074 mm accounts for 70%.
How to judge some faults of the ball mill?
   There are many reasons for the failure of the ball mill :