External heating rotary kiln

There are continuous and intermittent types, with heating energy sources including electricity, natural gas, blast furnace gas, liquefied petroleum gas, coke oven gas, or diesel.

The material in the externally heated rotary kiln does not come into direct contact with the heating energy. The drum is generally made of heat-resistant stainless steel, heated through the drum wall by radiation from the heating furnace. The drum is equipped with a material turnover plate to ensure even heating. The furnace body is typically made of all-fiber structure or a mixture of fiber and lightweight refractory insulating bricks. The drum is made of stainless steel with different materials based on temperature. Due to market limitations on the heat-resistant steel material for the drums, the internal material temperature of the externally heated rotary drum is ≤900°C.

Continuous rotary kilns are widely used in the market due to their high degree of automation, suitable for materials requiring a holding time of ≤4 hours and no special heating requirements. Intermittent rotary kilns are appropriate for materials with longer holding times, specific gas flow requirements, or those with certain demands on heating rate and sealing.