Rotary furnace: the rotary body is made of steel material; the liner is refractory material; the body is supported by couples of supporting roller and the gradient is 3%-6%. The motor drives the gear and the furnace rotates along. Materials are fed into the furnace from the higher tail end and discharged from the lower head end. At the head end, fuel (coal powder, heavy oil and gas fuel) is injected into the furnace and burns inside; and the smoke is discharged from the tail end. The rotary furnace is mainly used in cement industry to calcine cement clinker. Also it is applied to calcine pellets and powder or dry raw materials in refractory and ceramic industry. In chemical industry, it is widely used for drying, dewatering and calcining raw materials.