KINETICS OF REDUCTION OF MILLSCALE BY COAL - EFFECT OF PROCESS VARIABLES

The kinetic aspects of and the effect of process variables on the redu ction of millscale by coal were studied at four different temperatures from 1173 to 1323 K, particle sizes from 0.51 to 2.03 mm, coal/millsc ale ratios from 0.5 to 1.00, and bed depths from 25 to 51 mm. The kine tic data of reduction fit the Ginstling-Brounsthein kinetic model, The activation energy for the reduction was found to be 147 kJ mol(-1), W ithin the range of variables studied an increase of reaction temperatu re and coal/millscale ratio results in a high reduction rate, whereas an increase of average particle size and bed depth decreases the reduc tion rate. Optical micrographs of the reduced masses show the distinct appearance of metallic phase and the disappearance of wustite phase w ith time and temperature.