The air refrigeration, drying, freezing and pulverizing of the colloidal particles, and colloidal powder backheating are implemented in a closed system, i.e. the compressed air delivered from the air compressor is heat-exchanged with tail gas and pulverized colloidal particles is then expanded for refrigeration. The raw material colloidal particles are frozen by cold-air in the closed system, then pulverized so as to obtain the fine colloidal powder. The raw material colloidal particles can be dried by heat-exchanged tail gas, and the dried colloidal particles and backheated colloidal powder don't cluster. Said process is low in power consumption, and can be controlled by computer. |