Partial Metallization of Coal-Added Pellets for Smelting Reduction

Abstract

In NKK's Duplex-DIOS process, maximum annual productivity is obtained when a DIOS reactor is operated with 30% metallized feed . Laboratory tests were performed to ascertain if 30% metallization could be achieved consistently and with sufficient strength by adding coal less than the stoichiometric requirements. Partially metallized pellets were prepared using an LTV Steel Mining filter cake sample by adding coal in the amount of 35% of the stoichiometric requirements to both unfluxed and fluxed pellets. The optimum temperature of induration was in the range of 1200° to 1300°C. The product analyzed 25 to 30% metallization with compression strengths of 150 to over 300 lb, and apparent densities of 3.4 to 3.5.