A Calcination Rotary Kiln is a direct fired, refractory lined equipment for high temperature applications where it is necessary to change the 'state' of the material in a continuous process or in batch type process. Since this process usually requires a long residence time, the length to diameter ratio is often in excess of 10:1 in a continuous kiln. In most cases an oil or gas burner fires directly into the discharge end of the unit. The material is heated in three ways - by radiation from the burner flame, conduction from the refractory lining and convection by contact with the hot gases. They are also used for roasting a wide variety of ores.
Rotary kilns are used for the calcinations of Titanium dioxide, Illeminate, kaolin, Barium Carbonate, Magnesium Carbonate, Silica Gel, Lime, Activated Carbon, Vermiculite, Barium Sulphide, Magnesium Oxide, Petroleum Coke, Clay, Gypsum, Alumina etc.