Influence of Carbothermal Reduction Process on the Microscopic Properties of Lime-Free Roasting Chromite Ore Processing Residue (COPR)

Abstract

Abstract The lime-free roasting chromite ore processing residue (COPR) was more environmentally friendly than the lime-based COPR. And its components in lime-free COPR should be reused as secondary resource. The process of carbothermal reduction associated with magnetic separation was adopted in this study to reclaim the iron oxide in lime free roasting COPR. The microscopic properties of COPR samples treated by carbonthermal reduction were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), etc. The effects of process parameters on iron recovery rate were studied by single-factor experiments. The results indicated that the carbothermal reduction roasting process was beneficial to the destruction of the iron-rich spinel in the original lime-free roasting COPR and the enrichment of iron metal in lime-free roasting COPR. The optimal conditions were obtained as follows: reduction calcination temperature of 1100 °C, reduction time of 2 hours, coke ration of 3.5 times of theoretical content. The main components of the separated fraction were iron particles and some magnesium aluminum spinel.