The dingbo Three-ring Micro Powder Mill(ultrafine mill)is for supper-fine grinding materials with hardness less than 6 in Moh's scale and humity less than 6 percent such as kaolin,limestone,calcite,marble,talcum,barite,gysum,dolmite,graphite mud,mica,pyrophyllite,diatomite,graphite,alunite,fluorite,potassium fldspar,phosphorite,pigment and so on.The granularity of the end products is 325-2500 meshes(0.044-0.005mm).