At present, the commonly used mineral processing equipment in mineral processing plants include crushing equipment, grinding equipment, screening equipment, magnetic separation equipment, and flotation equipment.
The following is an analysis of the wearing parts of these equipment and the main causes of wear.
At present, the commonly used crushing equipment includes jaw crusher, cone crusher and impact crusher.
The wearing parts of jaw crusher mainly include movable jaw, tooth plate, eccentric shaft and bearing. The wear of the cone crusher is mainly the wear of the frame and the spherical bearing, the wear of the main shaft and the cone bushing, the wear of the thrust plate and the gear, the wear of the crushing cavity and the wear of the eccentric bushing. The wearing parts of the impact crusher are mainly blow bars and impact plates.
In the actual production process, the abnormal wear of wearing parts is not only related to the structural defects of the equipment, but also mainly related to the hardness of the material, the coarse particle size of the material, the unsatisfactory lubrication effect of the equipment, and environmental factors.
(1) Structural defects of the equipment
A large part of the wear of equipment is caused by defects in equipment installation, such as small clearance of structural parts, skewed structural parts, unreasonable installation angles, etc., which lead to uneven operation of equipment parts or uneven contact strength, resulting in serious local wear.
For example, the wear of the eccentric shaft of the jaw crusher is often due to the unreasonable rotation of the sealing sleeve and the cone sleeve, which causes the cone sleeve to lose the top tightening force and cause the eccentric shaft to loosen.
(2) The hardness of the material is too large
Material hardness is an important factor affecting the crushing efficiency of the crusher, and it is also the main factor that causes the wear of the tooth plate, crushing cavity and other parts that directly contact the raw material. The greater the hardness of the material is, the greater the difficulty of crushing, so that the crushing efficiency of the crusher is reduced, the wear speed is accelerated, and the service life of the crusher is shortened.
(3) Improper feeding size
If the feeding granularity is inappropriate, it will not only affect the crushing effect, but also cause serious wear of the tooth plates, brackets and gaskets. When the feeding granularity is too large, the crusher with sliding structure will be more seriously damaged.
(4) Insufficient lubrication of equipment
Insufficient lubrication is the main reason for bearing wear, because the bearing is subjected to a large load in production, which makes the bearing have a large friction during operation, thus causing the bearing to suffer severe wear.
(5) Environmental factors
Among the environmental factors, the biggest impact on the crusher is dust. The crushing operation of the crusher will generate a large amount of dust. If the sealing effect of the equipment is not good, the dust will damage the power system of the crusher on the one hand, resulting in serious wear of the power system; on the other hand, it will affect the lubrication system of the crusher, because the dust enters the lubricated part, it is easy to aggravate the wear of the lubricated surface.
At present, the commonly used grinding equipment in mineral processing plants includes dry ball mill and wet ball mill.
The ball mill works mainly through the steel ball impact minerals to achieve crushing, common wearing parts including lining plate, cylinder, grid plate, lining plate bolt, pinion and so on. And here are the main reasons for the wear of these wearing parts:
(1) Improper selection of ball mill lining plate material. Improper selection of the material of the lining plate will greatly reduce its anti-fatigue strength and life, not only unable to meet the operating requirements of the ball mill, but even cause plastic deformation or bulging.
2) The ball mill is not running normally. When the ball mill is in an abnormal operating state, the wear of the lining plate will be increased.
Under the normal operation of ball mill, the steel balls and the material are mixed together. When the steel balls are thrown down, they often do not directly impact the lining plate, but are blocked by the material mixed with the steel balls, which can protect the lining plate. However, if the ball mill runs at a low load, the steel balls will directly hit the lining plate, causing serious wear and even breakage of the lining plate.
(3) The running time of the ball mill is too long. The ball mill largely determines the processing capacity of the beneficiation plant. In beneficiation plant, ball mill has high operation rate and if it cannot be maintained in time, it will aggravate the wear and aging of the protective pad and lining plate.
(4) Corrosion in wet grinding environment. In beneficiation plant, regulators in flotation operations are usually added during grinding operations, so that the pulp in the ball mill has a certain acidity and alkalinity, which usually accelerates the corrosion of wearing parts.
(5) The material of the lining plate and the grinding ball do not match. There is a hardness matching between the lining plate and the grinding ball, and the hardness of the grinding ball should be 2~4HRC higher than that of the lining plate.
The screening equipment is mainly used for the classification of materials. There are many types of screening equipment commonly used in concentrators, including grading screens, high-frequency screens, linear screens, etc. The wearing parts of the screening equipment are mainly screen mesh, fasteners, bolts, etc. The main reasons for the wear of these wearing parts are ore properties, excessive feeding volume, and material impact.
(1)The properties of the ore
For screening equipment, the most common problem that affects the screening efficiency is the blockage of the screen holes, and the degree of blockage of the screen holes is closely related to the shape and moisture content of the feeding ore. If the water content of the ore is too high, the ore will be relatively sticky and not easy to separate, resulting in blockage of the screen holes; if the ore particles are long, it is relatively difficult to screen, and the screen holes will also be blocked.
(2) The feeding volume is too large
Excessive ore feeding will not only reduce the screening efficiency, but also cause ore accumulation or ore pressing, resulting in screen damage, coupling breakage, and screen box cracking. In production, the feeding should be as uniform and stable as possible to avoid overload operation.
(3) Material impact
For the screening equipment, the maximum force suffered during the operation is the impact force of the feeding material. The strong impact will not only cause the screen mesh to break, but also cause certain damage to the body and bolts of the equipment.
Magnetic separation equipment
According to the strength of the magnetic field, magnetic separators can be divided into weak magnetic field magnetic separators, medium magnetic field magnetic separators and strong magnetic field magnetic separators. At present, the wet drum magnetic separator is the most widely used, and the wearing parts include drum skin, magnetic block, groove bottom, transmission gear and so on.
Here are the main reasons that cause failure of the wet drum magnetic separator:
(1) Large-volume debris enters the magnetic separator. Large-volume debris enters the magnetic separator, which may scratch the cylinder skin, or even jam the cylinder, causing the equipment to stop; in addition, there may also be holes in the tank body, resulting in ore leakage in the tank body.
(2) The magnet block falls off. When the magnetic block in the drum of the magnetic separator falls off seriously, the shell of the drum will be scratched, and it needs to be stopped immediately for maintenance.
(3) The performance of the magnetic block is degraded. If the service life of the magnetic separator is too long, the performance of the magnetic block will be degraded, and the strength of the magnetic field will be reduced, which will affect the sorting effect.
(4) Poor lubrication. Poor lubrication can lead to problems such as wear and tear of the transmission gear.
The wearing parts of the flotation machine mainly include stirring device, scraper device, tank body, gate device and so on.
(1) Stirring device. The stirring device mainly refers to the impeller, whose function is to make the chemical and mineral particles fully contact, and plays an extremely important role in the flotation process. Serious failure of the stirring device will cause the flotation machine to press ore and affect the normal operation of the flotation machine. The common problems of the stirring device are mainly loose nut, poor lubrication, loose connection of the stirring part, etc.
(2) Scraper device. The scraper of the flotation machine is installed on both sides above the tank of the flotation machine. The scraper shaft is a super slender shaft, and the processing accuracy is difficult to control, so the problem of poor accuracy will occur. In addition, in the process of transportation and installation of the scraper device, due to hoisting, transportation deformation and other problems, resulting in the rotation of the scraper shaft is not flexible, the scraper shaft is broken.
(3) Tank body. The common problem of the tank body is water seepage or leakage, which hardly affects the beneficiation effect if it is not serious, but has a great impact on the surrounding environment. The main reasons for water seepage and water leakage in the tank body are weld defects, tank body deformation and the flange connection is not tight.
(4) Gate device. The gate device is a mechanism for controlling the liquid level. It is installed at the tail of the flotation machine. Frequent adjustment of the gate of the flotation machine will cause damage to the hand wheel. In addition, the more common gate failure is that the lifting is not smooth, and it is generally caused by poor lubrication of the screw, screw corrosion, jamming and other problems.