The spin flash dryer is used to mix and crush the bulk wet material and ensure that the particles do not stay in the high temperature zone of the drying chamber for too long. Therefore, there should be a reasonable gap between the stirring blade, the bottom and the wall of the chamber, and the rotation speed of stirring should also be selected reasonably. There is a good sealing device between the stirring shaft and the bottom of the drying chamber. The rotary flash dryer classifier is a ring with holes, similar to an orifice flowmeter, but at an angle. The diameter and height of the hole depend on the distribution of the product particles. When the height is constant, the smaller the pore size, the finer the particle size of the product. The addition of a grading ring in the flash drying cylinder is very important to control the particle size of the product, which greatly improves the product qualification rate.