A certain beneficiation plant uses the MQG2136 ball mill for grinding operations, but over time, the old equipment is unable to handle the existing work, resulting in a significant decrease in production efficiency. If new equipment is purchased, the cost will be higher. The beneficiation plant adopts a strategy of technological improvement to enhance the production efficiency of the MQG2136 ball mill. This article introduces improvement measures for you.
A certain number of grinding balls are installed in the cylinder of the ball mill. When the cylinder rotates, the grinding balls collide and rub with the material, causing the material to be finely ground. The motion state of the grinding ball during grinding is relatively complex, and there are generally three typical motion states: falling, throwing, and centrifugal motion. Among them, the grinding effect of the ball mill is better in the throwing state.
The critical speed rate of MQG2136 ball mill can be obtained from the formula for the street facing speed of the throwing motion, but the actual value of the throwing critical speed rate is often smaller than the calculated value. In order to improve the grinding efficiency of the ball mill, the speed rate of the ball mill needs to be above its critical speed rate. At the same time, appropriately increasing the cylinder speed of the ball mill within the critical speed range can improve the production capacity of the grinding equipment.
To this end, the parameters of the large and small gears in the transmission system were changed, and helical gear transmission was adopted to increase the speed rate of the MQG2136 ball mill from the original 80% to 88%, which can significantly improve productivity.
The appropriate filling rate is an important factor in determining the motion state of the grinding ball. A too small filling rate is also suitable for a relatively low rotational speed, resulting in insufficient impact force and difficulty in achieving the ideal grinding effect; On the contrary, if the filling rate is too high, the movement space of the grinding ball will become smaller, making it difficult to reach the throwing state, which will also affect the grinding effect.
Therefore, after strict calculation, the technicians adjusted the ball filling rate of the MQG2136 ball mill, controlling it between 40% and 50%, and monitored the filling rate in a timely manner. If it was too low, steel balls were added in a timely manner to improve the grinding efficiency.
After the increase in rotational speed, the selection plant found that the wear of the lining plate also showed an upward trend. In order to meet the demand and improve the service life of the lining plate, technicians studied the structure and materials of the lining plate and ultimately determined a type of lining plate that not only protects the inner wall of the cylinder, is more wear-resistant, but also plays a good role in improving the material.
The improved lining plate structure of the ball mill, as shown in Figure 3, replaces the original bolt fixed smooth lining plate with a rivet positioned waveform lining plate, overcoming various drawbacks such as easy cutting and difficult sealing of bolts. At the same time, the material has been improved by replacing the manganese steel lining plate with a rubber lining plate, greatly extending the service life, effectively reducing the consumption of lining plate materials, and improving the grinding efficiency and ball mill productivity.
The increase in rotational speed not only leads to an increase in liner consumption, but also makes the vibration of the mill more severe during operation. In order to alleviate this vibration, the selection plant adopts dynamic and static pressure technology. The use of this technology not only reduces energy consumption, but also makes startup and operation more stable.
The main bearings of traditional ball mills generally use sliding bearings, and the friction energy consumption between the shaft and the bearing accounts for 10% to 15% of the total energy consumption of the ball mill. The service life of the bearing is generally about three years.
Liquid dynamic and static pressure bearings combine the advantages of dynamic pressure bearings and static pressure bearings, while utilizing the static pressure effect of high-pressure oil and the dynamic pressure effect caused by rotation. The width to diameter ratio of the bearing's spherical pad is L/D=0.4 (taken as 0.35-0.5), with a diameter of D=870 mm, so L=348 mm, as shown in Figure 4.
After adopting this technology, the total energy consumption of the ball mill can be reduced by 8% to 12%, achieving energy conservation and consumption reduction of the ball mill, and improving its productivity.
After the above four improvements, the production efficiency of MQG2136 ball mill has been greatly improved, energy consumption has been correspondingly reduced, the consumption of lining plates has been reduced, and the cost of consumable parts has been saved. It can be said that it is a good measure to achieve multiple benefits with one move!
