The commonly used crushing equipment in mining plants is wet ball mills and rod mills. The two have similarities in appearance design and crushing principles, but there are also differences in structure, performance, purpose, etc. This article analyzes their differences from seven aspects and tells everyone how to choose a wet ball mill and a rod mill! From the analysis of the crushing principle, whether it is a ball mill or a rod mill, when the barrel section rotates, the grinding mill installed on the barrel body Under the action of sliding friction and centripetal force, the material (ball or rod) is raised to a certain height as the cylinder section rotates, and then dropped at a certain angular speed, thus causing impact, cutting and cutting to the material in the cylinder. Extrude it to break it. The principles are similar, but ball mills and rod mills differ greatly in key points, as shown below:

1. Appearance design and structural features

The ratio of the barrel section appearance design of the two is different. The ratio of the length to the diameter of the rod mill barrel section is generally 1.5-2.0, and the inner surface of the wear-resistant lining plate on the bearing end cover is a vertical plane. The ratio of the barrel section length to the diameter of the wet ball mill is small, and in most cases the ratio is only slightly larger than 1. In addition, the speed of the barrel section of the rod mill is smaller than the working speed of the wet ball mill of the same specification, so that the materials in it work in a cascading state.

2. Analysis of grinding materials

Rod mills commonly use round steel with a diameter of 50-100 mm to crush minerals, while wet ball mills use bearing steel balls to crush minerals. The difference in grinding bodies is the main difference between the two. There is a contact force between the bearing steel balls of the wet ball mill, and a line contact between the round steel balls of the rod mill, so the working characteristics of the two are significantly different.

3. Type analysis (different methods of discharging ore)

Among wet ball mills, the common ones are grid-type wet ball mills and overflow-type wet ball mills (named from different structures of the ore discharge parts), while rod mills do not require square plates to discharge ore, and only have overflow-type wet ball mills. There are two types: open-mouth type. The diameter of the hollow shaft at the ore discharge end is generally larger than that of wet ball mills of the same specification.

4. Analysis of material filling rate

The material filling rate refers to the percentage of crushed minerals in the capacity of the ball mill. For different crushing methods, ball mill structures, operating conditions and material shapes, the material filling rate has a suitable range. Too high or too low will affect the crushing effect. Generally, the filling rate of wet ball mill is 40%-50%, and that of rod mill is 35%-45%. In addition, the filling rate of autogenous mill is 25%-40%, and the filling rate of gravel ball mill is about 43%. .
5. Reliability analysis

The wet ball mill has no inertia impact during operation, which ensures the normal operation of the equipment, reduces the shutdown time of the equipment, and improves production efficiency.

6. Analysis of main uses

When re-selecting or beneficiating tungsten tin ore and other non-ferrous metal ores, a rod mill is often used to avoid over-crushing; in the second-stage crushing step, a rod mill is generally used as the first-stage crushing equipment to produce The quantity is large and the efficiency is high. When crushing iron ore that is too soft or not too hard, a rod mill can be used instead of a short-head cone crusher for crushing. It is not only easy to configure, but also low in cost, and it can also simplify ash removal in the work workshop. change. The wet ball mill grinds raw materials carefully and is prone to over-crushing, so it is not suitable for re-selection of production lines in metal smelting plants.

7. Characteristic analysis

The processing characteristics of the rod mill are that the material is less smooth, but the particle size distribution is even, contains less coarse particles and slime, and the over-crushing is relatively light, and the particle size distribution characteristics of the rod mill material are related to the conditions of rod crushing of iron ore. . The characteristics of wet ball mill are high production capacity, strong adaptability to raw materials, high degree of fineness of raw materials, fine feed particle size distribution, easy fine grinding, obvious environmental protection and energy saving, but its over-crushing condition is serious.