High-temperature chlorination of different cobalt oxide phases using calcium chloride

High-temperature chlorination method has been proposed for the recovery of value metals from industrial solid wastes. However, there are only a few reports about the effect of different occurrence states of value metals. The aim of this paper is to investigate the high-temperature chlorination of different cobalt (Co) phases using calcium chloride and phase evolution of Co oxide phases during high-temperature chlorination. Complex oxides of CoFe2O4, Co2SiO4, and CoAl2O4 were synthesised first. Concentrations of samples were measured by inductively coupled plasma-optical emission spectrometer (ICP-OES) after acid dissolution. Phases of calcines roasted at different times were detected by X-ray diffraction. The results showed that Co volatilisation percentages of different Co oxide phases at 1273 and 1373 K could be classified as CoO > Co2SiO4 > CoFe2O4 > CoAl2O4. Co volatilisation percentage decreased with the introduction of Al2O3 due to the generation of CoAl2O4 from the reaction between CoO and Al2O3. The phase evolution of different Co oxide phases during the high-temperature chlorination was described in detail.