Rotary Calciners & Kilns


Thermopower Furnaces is a specialist of custom designed rotary kilns. Rotary kilns are typically run at significantly higher temperatures when compared to  rotary dryers. Rotary Kilns drive a physical or chemical change to the processed material which may require either oxidizing, reducing or inert gas atmospheres within the rotary tube. Rotary kilns allow for continuous processing on a wide range of materials at high throughputs.

Indirectly Heated Rotary Kilns

Indirectly heated rotary kilns continuously mix the product in a controlled atmosphere exposed to accurate temperature control and heat transfer (radiation, conduction and convection) achieved by multi-zone temperature control along the length of the rotary tube. Thermopower Furnaces’ indirectly heated kilns can operate at temperatures up to 1100C.

Directly Heated Rotary Kilns

Thermopower Furnaces also offers directly fired rotary kilns with refractory linings where temperatures in excess of 1500C are achievable. Direct heating can be introduced from separate combustion chambers or by means of a burner fired directly into the rotary tube. Thermopower Furnaces has developed unique and efficient heating systems  in directly heated rotary kilns as a result of its continuous effort to innovate and offer optimal  efficiencies in its thermal engineering solutions.

Rotary Kiln Specifications

  • Indirectly or directly heated rotary kilns.
  • Co-current gas flow or counter current gas flow arrangements.
  • Controlled atmospheres if required.
  • Electrically heated, gas heated, fuel oil heated or waste gas heated (subject to availability).
  • Variable residence times (Adjustable tube speed, kiln angle and feed rates).
  • Variable feed particle sizes from powders through to granules and lumps.
  • Easily coupled with Gas Abatement equipment such as Heat Exchangers, Waste Heat Recovery Systems, Cyclones, Baghouses, ESPs, Condensers etc.
  • Local PID Dryer Control or Remote PLC Control available. 
  • Agitation and Knocking systems available.
  • Various material feeding options (Gravity chutes, vibratory feeders, screw conveyors, belt conveyors, etc.).


  • Roasting – the oxidizing of minerals at elevated temperatures under oxidizing conditions.
  • Reduction – the reduction of minerals from a high oxide state into either a lower oxide state or to a completely reduced state under reducing conditions