In crucible reduction of mill scale by lean grade coal: Study of time, temperature and arrangement for optimum reduction conditions

Abstract

The research work involves the reduction of mill scale by lean grade coal with limestone powder (90% lean grade coal + 10% limestone powder) in an alumina crucible. The ratio of mill scale and coal with limestone powder was taken in the ratio of 1: 1.25 and all raw materials of particle size ranging between 90 to 150 microns. Study of the effect of reduction time (60, 90, 120 minutes), temperature (850, 900, 950°C) and arrangements (mixed, central, alternate concentric) in crucible have been investigated. It has been found out the mill scale sample reduced for 90 minutes at 900°C in the alternate concentric way, showed the optimum conditions for reduction, in which metallic iron found to be 64.64% and the corresponding degree of metallization is 96.0516%. With the increase in time and temperature, reduction increases and later becomes constant or shows very slow inclination in reduction value.