DESIGN MODIFICATIONS AND ADAPTATION OF AN OXIDISING MULTIPLE HEARTH ROASTER FOR REDUCTION ROASTING

Significant differences exist between the design and operation of the reactors meant for oxidation roasting and reduction roasting. Also, reduction process is often associated with handling of hazardous/toxic gases. A pilot scale Multiple Hearth Roaster (MHR) was originally procured for oxidation roasting of ores and concentrate. In this paper, the stepwise procedure for converting an oxidising MHR for carrying out reduction roasting is discussed in detail. The MHR which has been converted for reduction roasting can operate below 800°c with a reduction potential [CO/ (CO+CO2)] of less than 0.6 under a positive pressure of 1-5 mm WG.