Wet process for the classification of super fines

摘要

Wet process for the classification of super fine particles, especially to obtain fines with a very small maximum grain size and to produce particles with a narrow particle-size distribution. The average and maximum size of fines can be significantly reduced in comparison with previous wet classification methods for fine grains. The process is characterized by low energy consumption and a constructively simple design. According to the invention the process consists of two steps. In the first step the suspension to be classified is filtered using a cross flow filtration module (2) with a constant flow rate of the suspension in the module and a constant regulated filtrate flow (6, 7), whereby the fines (3) are deposited as a layer of particles on the microporous filter areas or membrane surfaces of the module. In the second step a fine grained product is obtained from the deposited layer of particles by placing cross flow filtration modules in the circulatory or cascade system.