Introduction to the characteristics of four common grinding equipment

As the main equipment of mine beneficiation, grinding equipment can be roughly divided into four types. These four categories are rod mills, energy-saving ball mills, lattice ball mills, and overflow ball mills.

1. Rod mill

Scope of application of rod mill

Using advanced controllable feeding and discharging technology, combined with the actual grinding materials, suitable grinding bodies should be used, and the traditional surface contact should be changed to line contact so that the discharge particle size is more uniform, the output is higher, and the price is reasonable. It is widely used in Refractory, chemical, metallurgy, glass, and other industries that have high requirements on the uniformity of the finished product after grinding. In recent years, it has also been used in the sand-making industry of construction sand.

Rod mill working process

The rod mill is driven by the motor through the reducer and the surrounding large gears, or by the low-speed synchronous motor directly through the surrounding large gears to drive the cylinder to rotate. Appropriate grinding media – steel rods are contained in the cylinder. Under the action of centrifugal force and frictional force, the grinding medium is lifted to a certain height and falls down in a state of throwing or leaking. The ground material continuously enters the cylinder through the feeding port, is crushed by the moving grinding medium, and discharges the product out of the machine through the force of overflow and continuous feeding for the next stage of operation.

2. Energy-saving ball mill

The working principle of energy-saving ball mill

The energy-saving ball mill is a horizontal cylindrical rotating device, driven by an outer gear, two bins, and a lattice-type ball mill. The material enters the first chamber of the mill spirally and evenly from the feeding device through the feeding hollow shaft. There are stepped lining plates or corrugated lining plates in the chamber, and steel balls of different specifications are installed inside. The rotation of the cylinder generates centrifugal force to bring the steel balls to a certain height. After falling down, it has a heavy impact and grinding effect on the material. After the material reaches the rough grinding in the first warehouse, it enters the second warehouse through the single-layer partition board. The warehouse is inlaid with a flat-lining plate and has steel balls to further grind the material. The powder is discharged through the discharge plate. The energy-saving ball mill of Weifang Guote Mining Equipment Co., Ltd. can achieve an energy-saving efficiency of 70% during operation, which greatly saves energy consumption.

Structural features of energy-saving ball mill

It consists of main parts such as the feeding part, discharging part, rotating part, transmission part (reducer, small transmission gear, motor, electric control). The hollow shaft is made of cast steel, the inner lining can be removed and replaced, the large rotary gear is processed by casting gear hobbing, and the cylinder is inlaid with a wear-resistant lining plate, which has good wear resistance. The machine runs smoothly and works reliably.

The ore mined from the mine is crushed by the jaw crusher or the two-stage closed-circuit crushing system composed of the jaw crusher and then reaches a reasonable particle size and fineness, and then is evenly sent to the energy-saving ball mill through the elevator and the feeder. The ball mill grinds and pulverizes the ore. Then the ore that has been ground by the energy-saving ball mill enters the classification equipment for classification treatment, and the ore that does not meet the particle size requirements is returned to the ball mill for circular grinding until it reaches the reasonable particle size requirements.

3. Lattice ball mill

Lattice ball mill features and advantages

1. The advantage of the grid ball mill is that the discharge speed is fast, which can reduce the over-crushing of the ore and increase the output per unit volume;

2. The discharge end of the lattice ball mill adopts a cone design, which not only increases the volume but also forces the steel balls at the cone end to be classified. The closer to the outlet, the smaller the diameter of the steel balls, which increases the effect of repeated grinding and improves the fineness of the material. the degree is further improved;

3. The grid type ball mill adopts a grooved ring lining plate, which increases the contact surface of the ball ore, strengthens the grinding effect, and can lift the ore and reduces the power;

4. The grid-type ball mill has a fast ore discharge speed, which can reduce the over-crushing of the ore and increase the output per unit volume at the same time.

5. The upper limit of the particle size of the grinding product of the grid ball mill is generally 0.2 ~ 0.3mm, so it is often used in the first stage of grinding, and often forms a closed loop with the spiral classifier. The grid-type ball mill can discharge qualified products in time, reduce the over-grinding of ore, and has high grinding efficiency. When the particle size needs to be ground to a uniform product of 48-65 meshes, it is better to use a grid-type ball mill.

4. Overflow ball mill

Features of overflow ball mill

1. The transmission of the overflow-type ball mill adopts large double-row spherical roller bearings instead of sliding bearings, which greatly reduces the friction during the rotation process, makes it easy to start, and saves 20-30% of the motor energy.

2. The inner lining plate of the overflow type ball mill adopts a corrugated type, which makes the lining plate have a greater lifting force on the steel ball during the rotation process so that the steel ball can reach a higher height, and the impact force caused by the falling is larger, which makes the grinding The ore effect is better, and the grinding effect is strong.

3. The overflow-type ball mill adopts an integral frame structure, which is convenient for civil construction and equipment installation.

4. The overflow-type ball mill has a relatively simple structure and a high operating rate.

Scope of application of overflow ball mill

Overflow ball mills are usually used for the fine grinding of mineral materials. Generally, a grid-type ball mill is used to form a two-stage closed-circuit grinding system. The grid-type ball mill has a large processing capacity, and the overflow-type ball mill has a relatively small processing capacity.