The ball mill is mainly composed of barrel, ore feeding, ore discharging, bearing, transmission and lubrication system. During operation, the material is sent into the cylinder by the ore feeding department, and the cylinder will rotate around the horizontal axis according to the specified speed. At the same time, the ore will do free falling or throwing movement through centrifugal force and friction of grinding medium, from which the mineral will be crushed by the impact of medium, cylinder wall and its own three-phase, grinding and stripping, and the crushed material will be discharged through the ore discharging department.
According to the ore discharge mode, ball mills can be divided into lattice type and overflow type. According to the classification mode, we can know that their names are different. In addition, what is the difference between the two ball mills?

Grid ball mill:
The grid type ball mill is equipped with a grid lining plate on the discharge side, which is also named after it. There are many 7mm-20mm discharge holes on the grid plate. The materials ground by the ball mill will pass through the lattice lining plate, and the side of the lattice plate close to the ore discharge end is equipped with a ore lifting device, which is a radial rib, which divides the lattice plate and the end cover into several fan-shaped chambers leading to the hollow journal. When the ball mill rotates, the radial ribs play the role of lifting the pulp, lifting the pulp discharged from the small holes on the lattice plate to the hollow shaft neck for discharging ore, and discharging it from the ball mill through the hollow shaft neck.

Overflow ball mill:
There is no lattice lining plate installed on the discharge side of the overflow ball mill, but spiral blades with the spiral direction opposite to the rotation direction of the mill are installed on the inner surface of the hollow journal bushing at the discharge end, in order to prevent water pellets or coarse ore blocks from being discharged together with the pulp. The discharge of overflow type ball mill overflows automatically by the height of the pulp passing the lower edge of the hollow journal bushing, which is the reason why the overflow type ball mill is named.

When buying ball mills, how to choose?
1. Select according to the particle size of mineral discharge
Generally, the upper limit of the particle size of the grinding products of the lattice ball mill is generally 0.2 ~ 0.3mm, so it is often used in the first stage of grinding, and often forms a closed cycle with the spiral classifier.
The particle size of overflow ball mill grinding products is generally less than 0.2mm, which is suitable for concentrate regrinding operation. It can be used as one-stage grinding or two-stage grinding operation, and can obtain fine qualified products.

2. Select according to the size of production capacity
The lattice ball mill relies on the lattice plate for forced ore discharge, so the production capacity is higher than that of the overflow ball mill. The overflow ball mill discharges ore by gravity, which is slow and relatively weak in production capacity. In addition, due to the long retention time of materials in the ball mill, it is easy to have over crushing.

3. Select according to the grinding effect
The steel balls in the cylinder of the lattice ball mill will be fed in proportion to the size, and when the steel balls of the ball mill are raised to a certain height, and the relatively low pulp surface has a large falling height for the steel balls. Therefore, the steel balls have a strong impact on the materials, a large crushing effect on the minerals, and a better grinding effect. The grinding efficiency of overflow ball mill is relatively weak.

4. Select according to the difficulty of maintenance
The overflow type ball mill has relatively simple structure and convenient maintenance due to the lack of grid plate configuration. Although the grid type ball mill has a good ore discharge effect due to the grid plate, it also makes the central vent of the grid in the ore discharge section, the gap between the grid joint and the compartment plate easy to be blocked by the slurry, which increases the difficulty of maintenance and inconvenient maintenance.

The above four aspects are some standards you need to measure when choosing a ball mill. No matter which one you choose, users need to clarify their production needs. However, it should be noted that each mine is different, even if the same kind of ore is also different. Therefore, before choosing a ball mill, you must do a good job in beneficiation test, and carry out concentrator design and equipment selection according to the test results. In this way, the selected ball mill is the ball mill you need.