... )kaolin,ceramics and slags,etc. 3)with the mohs hardness below 8 YGM high pressure ultrafine powder making machine,very popular in ... used to ultrafine the non- explosive materials of Mohs Hardness≤ 6 and humidity≤ 8%, such as kaolin, limestone, calcite, marble, barite, gypsum ... , cerames, ahd slags, etc, below scale 9.3 of Mohs hardness and 280-odd sorts of non-inflammable and non-explosive ...