Mitchell Rotary Calciners, or kilns, are very similar in design to rotary dryers, except that much higher temperatures are involved. Again these may be directly heated or indirectly, depending upon the specific application.
Directly Heated Calciner
The refractory lined rotating shell has no lifting flights. Forward flow of the material is effected by the slope and rotation of the shell. Located at the discharge end, a gas or oil burner enables air temperatures up to 1650°C to be achieved. For certain applications, the atmosphere within the kiln can be controlled to give oxidising, or slightly reducing conditions.
Indirectly Heated Calciner
Based on the design of the indirectly heated rotary dryer, the calciner is capable of operating at temperatures of 1100°C. Typical applications include: nickel catalysts; carbon regeneration, molecular sieves and china clay.