... The Grinding Mill is designed to produce super-fine pwoder or micro powder of different materials with hardness less that 6 ... than 6 percent such as kaolin, limestone, calcite, marble, talcum, barite, gypsum, dolomite, bentonite mud, mica, pyrophyllite, sepiolite, diatomite, graphite, ... year, which is 2-3 times longer than impact mill or turbo mill. Furthermore, the lifetime can reach 2-5 years ...