Wet grinding technology of grinding mill
The ginding mill are usually used in wet grinding equipment. The equipment has high energy consumption, large investment, but significant dispersion function, and can improve the shape of particles, so it is used in most post-processing devices. There are many production plants in China, and the products are widely used in the paint and coating industry, but there are few sanding machines for the production of titanium dioxide, and the equipment specifications are relatively small. For the 10,000 ton titanium dioxide production device, it is appropriate to use the introduced large sanding machine. There are vertical and horizontal sandmill, vertical for normal pressure operation, horizontal can run under a certain pressure. These two forms are used in the production of titanium dioxide abroad. The cylinder of the sander should be wear-resistant metal materials, or wear-resistant non-metallic materials. Considering that the abrasion of the cylinder may cause pollution to the product, wear-resistant non-metallic materials should be preferred. The working medium of the sander has sand or beads, and the requirements for these working medium are that they have wear resistance and high density. The more suitable sand is Ottawa sand with sand diameter less than 1mm. The grinding effect of the sand mill is the basic requirement of the selection of the sand mill. The particle size of the semi-finished titanium dioxide (the material after Raymond or oxide) is less than 325 mesh. For high quality titanium dioxide products, the particle after grinding has been greatly improved compared with the previous gravity settlement classification control of 5μm, and the requirement is below 1μm. This is difficult to achieve for just the use of mixing, and for the introduction of the sand mill, it can basically meet the requirements. For the calibration of the production capacity of the sand mill, due to the lack of experience of domestic manufacturers, foreign operation data is also less, coupled with the characteristics of the material and the pre-dispersion status and other factors, so it is difficult to generalize, some manufacturers use residence time to determine the ability, but it involves the concentration of the material and the quality of the grinding state and other factors, It is not scientific to use residence time to calibrate, instead, it is the energy consumption of grinding injection. For horizontal sander, the energy consumption of grinding is about 40kW/h/tTiO2, that is, the production capacity of the sander can be obtained by dividing the real power consumption of the sander by the energy consumption per unit product. For the vertical sander, the grinding energy consumption is about 80kW/h/tTiO2. On the surface, the production capacity of horizontal and vertical sanding machines is very different. In fact, the production capacity of sanding machines should be determined according to the material characteristics and grinding requirements. If necessary, tests should be carried out. After sanding, TiO2 particles in the slurry have been well dispersed, which can meet the requirements of the coating. However, in the process of sanding, sand or ball abrasion is objective existence, and sometimes there is the possibility of breakage. When the particle size of sand or ball is less than a certain size, it will flow out of the sanding machine with the material. These particles have no pigment performance, and mixed with the product will have an impact on the quality, but also affect the subsequent processing equipment, and may even cause damage to the equipment. These impurity particles need to be removed for this purpose.