... is invented through more than twenty times experiments and improvements, and based on twenty years of mill manufacture experience ... mohs, such as calcite, chalk, limestone, dolomite, kaolin, bentonite, talc, mica, magnesite, pyrophillite, ceyssatite, barite, gypsum, alunite, granite, ... the separator makes the coarse powder drop down and regrinded and the fine powder shall go into cyclone powder ...