There are three working processes for vertical mill including grinding, drying and powder selection. Only when these three processes all run well, the operation of the whole vertical mill will be stable.
In order to dry the moisture in raw materials, the whole system of vertical mill needs to be preheated for a period of time before starting the vertical mill. It should be heated continuously and slowly, and can’t be local overheating. Otherwise, the vertical mill system under low temperature will take more heat away in the process of drying raw materials, and the finished products will not be dried, so that the same problem will happen when raw materials are transported into storage and extracted from the bin. Similarly, raw materials maybe blocked in the grinding area. The raw materials stick to the grinding rolls and discs, resulting in excessive vibration and material overflow.
It is also necessary to heat the vertical mill to avoid excessive hot pressing among the grinding parts, rolls and discs. Because the weight and thickness of grinding rolls and discs are larger, the inner temperature of these components will be lower than that of the outer layer for a long time. This non-uniform temperature distribution will cause the hot pressure which can crack these hard parts. Therefore, the increase of inlet temperature of vertical mill should be carried out slowly.
