Centrifugal Classification of Kaolin Minerals by Wet Processes

Abstract

Kaolin minerals produced in Japan are mostly impure, containing such impurities as pyrite, iron oxide, free quartz, sericite and montmorillonite. For this reason attempts have been made to improve the quality of kaolin minerals in refining industries by removing the impurities as much as possible both chemically and physically.
The centrifugal classification of domestically produced kaolin minerals was the object of our study performed by the wet method on an industrial scale as an important process in refining, and the following facts were confirmed as the result of the study.
(1) The classification up to d₅₀=4μ of overflow products is made easy by the use of a multiple small-sized liquid cyclone.
(2) The classification up to d₅₀=0.6μ of overflow products is made easy by centrifuging the material continuously, and the free quartz contained as impurities can be separated to some extent.
It is recommended therefore that, when the centrifugal classification of kaolin minerals is to be processed by the wet method, while a cyclone, whether large-sized, medium-sized, or small-sized, or a multiple ultra small-sized liquid cyclone, will be used with much industrial advantage according to the range of particle sizes from coarse to microscopic fine, a centrifuge will as advantageously be used for the ultra-microscopic particles.