Assessment of Reduction Behaviour of Low-Grade Indian Hematite Iron Ore Pellets by Non-Coking Coal

Studies on isothermal reduction behaviour (with coal) of fired pellets of low-grade hematite iron ore were performed in the temperature range of 1123–1223 K. A rise in temperature considerably improved the reduction rate, and this was sharper up to about 45–55% reduction. An increase in firing time from 1 to 3 h at 1573 K decreased the degree of reduction in resulting fired iron ore pellets. Fired iron ore pellets made with molasses exhibited slightly higher % of reduction values than those prepared under identical conditions by the addition of bentonite. Abnormal swelling was not observed in any of the reduced pellets. Kinetic model equation, 1-(1-f)1/3=kt\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${1-(1-f)}^{1/3}=kt$$\end{document}, was noticed to fit well for the experimental results, and computed apparent activation energy values were found to be in the range of 15–16 kJ mol−1, indicating overall reduction rate to be controlled by both the chemical reaction and gaseous diffusion processes.