Thermogravimetric Studies on the Reoxidation of Direct Reduced Iron at High Temperatures

Abstract

Thermogravimetric (TG) data on reoxidation behaviour of a particular type of sponge iron (coal based sponge iron) are mainly reported in this paper. While emphasis is on isothermal kinetics, some nonisothermal TG data are also presented. The data have been analysed using the reduced time plot and the activation energy values evaluated using both integral and differential approaches. The kinetic analysis developed has been used to establish the reaction mechanism which is found to be essentially of the first order. The paper also discusses the general importance of high temperature studies in the assessment of reoxidation behaviour of sponge iron and how the outcome of this investigation may be useful for devising means to protect sponge iron against reoxidation and spontaneous combustion.