Factors Affecting Grinding Efficiency

Grinding operation is a very important process in the concentration plant, in which the material is ground after being crushed. The grinding equipment is an indispensable part of the concentration plant, but its infrastructure investment has a large proportion. At the same time, the steel consumption and energy consumption are very high. According to statistics, the energy consumption of the grinding operation accounts for 65% to 75% of the total energy consumption of the concentrator; the steel consumption accounts for almost 100%, and the grinding cost accounts for 50% to 70% of the total cost of the concentrator. Therefore, a proper grinding machine is the key to improve grinding efficiency and bring great economic benefits to concentrator.

There are many factors affecting the grinding efficiency, which can be roughly summarized into two aspects: materials and grinding mill.

1. Effect of Materials on Grinding Efficiency

The influence of materials on grinding efficiency is mainly reflected in the material properties and the grinding grain size. Different ores have different properties and different hardness, and the corresponding grinding process is also different. For example, fluorite ore, tin ore, etc., which are easily crushed, are different from other ores, and attention should be paid to not to over-grinding.

The coarser the grinding input grain size, the longer the time required to grind into proper output size for the dressing requirement and the greater the wear and tire to the grinding equipment is. At present, more crushing and less grinding is one of the main principles of the design and production of the concentrator. For the ore of the same nature, the higher the fine fraction content of the milled material, the higher the grinding efficiency is.

2. Effect of Grinding Mill on Grinding Efficiency

After determining the nature of the ore, it is necessary to choose the right grinding mill. As far as the internal structure of the grinding mill is concerned, it can be roughly as follows: the medium and the liner. From the current state of use of domestic grinding mills, grinding media are mostly steel balls, steel rod and gravel. Years of research have shown that spherical media is the most efficient and cheapest in the usual particle size range, and ball media can open door to the finest grain size. In addition, the way media and materials and media and media contact also greatly affect the grinding efficiency. The application of steel grinding ball medium is widely used in China. But the crushing force of ball media is quite large due to the fact that the crushing method is mostly point contact, so it is easy to cause over-grinding phenomenon.The rolling property of the steel rod medium is slightly worse than that of the steel ball, but since it is a line contact, it can prevent the particle from over-grinding. It is therefore suitable for rough grinding and not for fine grinding. Moreover, the wear resistance and deformation degree of the grinding medium loaded by the mill are also greatly affected by the grinding. Therefore,when choosing a ball mill, you should also consider the parameters of the loaded media.

The lining plate is mainly used to protect the cylinder body, and avoid damage to the cylinder body caused by direct impact and friction of the medium and the material on the cylinder body. Because the liner is exposed to media and materials for a long time, it is easily damaged. According to the material, the liner can be divided into rubber lining, magnetic lining and ceramic lining. In the case of a rubber lining, the material is soft and acts as a cushion on the cylinder. In the rough grinding operation, the impact of the steel ball is buffered, which reduces the production efficiency of the grinding mill.

However,in the fine grinding operation, the steel ball is mainly based on the grinding and stripping effect, and the grinding effect is not obvious. The advantages of long life, energy saving and noise reduction of the rubber lining are reflected. Therefore, in the fine grinding operation, the rubber lining can save energy consumption and improve grinding efficiency. Magnetic linings are mostly used in grinding operations with iron elements,while ceramic linings are less used in beneficiation mills because of their bad wear resistance to impact.

The factors affecting the grinding efficiency are far more than these, and the various factors also affect each other. But the above factors are also the most basic factors in the selection of mills when setting up a concentrator. In general, grinding is an operation with high energy consumption and steel consumption, which directly affects the cost of mineral processing and subsequent separation index. It is recommended to conduct a detailed study on the grinding ability of ore in the test stage and select a reasonable mill in order to maximize economic benefits. “Suitable is the best!”