Slag mill grinding pressure is to control the finished product fineness of one of the main parameters. Due to the vertical slag mill | slag vertical mill roller itself has a certain weight in the production practice is mainly through the vertical mill hydraulic system to change the size of the grinding pressure to meet the needs of grinding materials. We have to master the law of production: the grinding pressure increases, the particle size of the material becomes smaller, the system yield increases. However, when reaching a certain critical value continue to increase the grinding pressure, the main motor current continues to increase, the unit power consumption of products increased, mill vibration may increase. At the same time, the abrasion of the grinding roller and the grinding disc is also increased, and the service life of the grinding roller is increased. On the contrary, the material layer of the grinding mill gradually becomes thicker, the main motor current increases, the pressure difference of the grinding mill increases, and the amount of the powder returned increases. When GRMS46 feed volume reached 90t / h, the grinding operation pressure was set to 6.5MPa during the commissioning of GRMS slag mill manufactured by chaeng. As the output of Taiwan's stage production gradually adjusted to 110t / h, the operations Pressure increased to 7.5MPa, the mill is in stable operation, and the finished surface area can reach 450-480m2 / kg control requirements.