Mineralogical studies and optimization of tabling parameters of low grade chromite ore by box behnken design of experiments

Abstract

Chromite ore is geologically associated with gangue materials which have lower density compared to pure chromite (FeO.Cr2O3). Gravity separation techniques are very suitable for beneficiation of low grade chromite ore. In the present study mineralogical analysis of the sample has been carried out by using Wavelength dispersive x-ray fluorescence (WDXRF), X-ray powder diffraction (XRD), Scanning electron microscopy (SEM) and Energy dispersive X-ray (EDX). The beneficiation of low grade (Cr2O3% 26.88) chromite ore has been investigated using wilfley table. Optimization has been carried out using box-behnken statistical design (BBD). The experimental parameters selected are: tilt angle, water flow rate and pre-heat treatment of the chromite ore. It is observed that percentage recovery of Cr2O3 depends upon tilt angle, water flow rate and pre-heat treatment of chromite ore. Pre-heat treatment of chromite ore plays a vital role in gravity separation. The optimized tabling conditions suggested by BBD are 8° tilt angle, 4 L∙min-1 water flow rate and temperature for pre-heat treatment of raw chromite ore at 443.72℃. After tabling under optimized conditions, chromite concentrate contained 1.91 Cr/Fe ratio, 46.02% of Cr2O3 with 65.95% recovery.