LAUSR

ABSTRACT The reduction of an Indonesian iron sand concentrate was studied using TG/DTA and XRD analyses. The iron sand concentrate was mixed with coal and formed into a cylindrical pellet. The experimental results show that magnetite was reduced into wustite at 700–800°C and into metallic iron at temperature above 800°C. The transformation of titanomagnetite into ulvospinel and ilmenite occurred between 900 and 1000°C, and ulvospinel transformed into ilmenite and iron at 1000–1100°C. To simulate the reduction process in a rotary kiln, iron sand concentrate pellets were hardened at 1250°C and reduced using coal, which was added to cover the surface of the pellet at a temperature range of 800–1100°C for 150 min. The reduction degree was calculated based on the weight loss and the metallization degree was determined by wet chemical analysis. Quasi-equilibrium values of the reduction and metallization degrees were obtained at a certain temperature. The reversible first-order kinetics equation was proposed to analyse the experimental data to predict the metallization degree as a function of the reduction time and temperature.