A Comparative Assessment of the Thermal Performance of Calcining Technologies in the Minerals Processing Industries

The calcination process is carried out in a variety of types of furnace, from the early batch process bottle kilns, through vertical shaft kilns, tunnel kilns and rotary kilns, to modern suspension preheater and flash calcination systems. Within each of these kiln groups there are, and have been, many variations, but it is notable that examples of all these kilns are still in use as production units. The paper reviews these various kiln technologies, with particular emphasis on the thermal performance of each type of kiln, and discusses how the overall thermal efficiency of each type of kiln can be improved, through a better understanding of the process and combustion conditions.