... leather using three different material for users to choose.Scope:1.Such as, coal powder, charcoal powder, metallic powder (Fe / Si powder ... iron oxide, carbon powder, charcoal powder, slag, gypsum, tailings, sewage sludge, kaolin, activated carbon, coke powder and other powder, powder, waste, waste residue ... The natural materials enter the ball roll mode with the roll rotation. 3. Material pressure on ...