Carbothermic Reduction of Misamis Oriental Chromite Ores

Abstract

This study was conducted to determine the non-isothermal and isothermal reduction of chromium ores in the solid-state by reductants like solid carbon under argon and hydrogen-argon atmosphere. Two different chromite ores from local sources , sandy chromite ore from Opol, Misamis Oriental (SCO) and lumpy chromite ore from Manticao, Misamis Oriental (LCM) were used in the study. Isothermal and non-isothermal experiments were conducted in a fixed bed reactor heated in a vertical tube furnace in the temperature range 800 to 1000°C. Raw chromite and reduced samples were subjected to phase analysis and morphology characterization using X-ray flourescence (XRF), X-ray diffraction (XRD), and energy dispersive x-ray spectroscopy (EDX). It was found that reduction does not go to completion at this temperature range. The early stage of reduction of iron was controlled by nucleation and the later by nucleation or chemical reaction or both. The activation energy at the early stage of reduction is estimated to be 44.76 kJ/mol and the later stage of reduction is 144 kJ/mol for SCO and 76.5 kJ/mol for LCM. The reduction of chromium was controlled by chemical reaction.