Heat-treatment of granular materials from rotary oven - incorporating size reduction rolls in vertical heating shaft with perforated angled walls

Granular solids leaving the discharge end of a horizontal rotary oven fall down a vertical shaft, wider at the base than at the top, its walls being angled and perforated. Through the perforations pass hot gases from burners, entering via a subdivided combustion chamber. Between the oven and the vertical shaft is a set of crushing rolls through which the solids pass and are reduced in size. After heat treatment in the vertical shaft the solid is conveyed to a horizontal heated grate for final treatment. Arrangement is for the heat treatment, in continuous flow, of solids such as cement clinker, to remove volatile contaminants and to give the necessary degree of size reduction. Good size reduction is obtd. with satisfactory removal of volatile chloro-compounds; minimum adherence of solids within the process unit.