Application of Vertical Roller Mill in the Production of Ultrafine Calcium Carbonate Powder
Vertical Roller Mill RPM Influence on the Grinding Efficiency:
Rotation speed of vertical roller mill is an important factor affecting the grinding efficiency. As the rotation speed increases, the friction between the grinding media and calcium carbonate is increased, so grinding efficiency is also improved. However, the rotation speed should not be too high. If The rotation speed is too high, the calcium carbonate will move out of the grinding contact surface, and the powder shape will be also influenced, and the vibration of the whole vertical roller mill will be higher. So the grinding efficiency cannot be improved. The suitable rotation speed is the right choice.
Calcium Carbonate Feeding Size Influence on the Grinding Efficiency:
If other conditions are all same, calcium carbonate size have a big influence on the vertical roller mill grinding efficiency. In order to reach the best grinding state, the feeding size should less than 50mm or 30mm(according to the mill size). There must be some bigger size (1-30mm; 40-50%); This will improve the grinding between calcium carbonate and calcium carbonate, and also improve powder shape. If the feeding material contains 80-90% powder (80-200mesh), it is not easy to form grinding layer between the roller and ring, so the grinding efficiency should be lower.
Grinding Aids Influence on the Grinding Efficiency:
Adding appropriate grinding aids during calcium carbonate ultrafine grinding can greatly improve the grinding efficiency and improve the dispersion performance of grinding products. The grinding aid mainly improves the grinding process by changing the hardness of the material and the interaction between the particles.
The ultrafine calcium carbonate powder can be successfully produced by vertical roller mill, whose fineness can meet the requirements of paper industry and painting industry. Rotation speed, feeding size and grinding aid are the main factors affecting the grinding efficiency of the vertical roller mill. In order to obtain high grinding efficiency, the grinding conditions should be strictly controlled.