Clean Utilization of CuCl Residue by Microwave Roasting under Oxygen-Enriched Condition

Abstract The clean utilization of the CuCl residue containing chloride produced from zinc hydrometallurgy residue is very important for the recycle of valuable metals. A new method of microwave roasting under oxygen enriched condition was put forward to strengthen the process of dechlorination. It was demonstrated that the dechlorination rate of CuCl residue by microwave roasting was higher than that of conventional roasting by tubular resistance furnace under the same conditions (temperature, holding time and atmosphere). After roasting at a temperature of 450°C for 120 min under an oxygen flow rate of 150 mL/min in microwave field, the dechlorination rate of CuCl residue was as high as 97%, increasing 17% compared to that of conventional roasting using tubular resistance furnace. The characterizations of phase variation of CuCl residue in microwave field by means of X-ray diffraction (XRD), scanning electron microscopy-energy dispersive spectrometer (SEM-EDS) and Raman spectroscopy indicated that the process of dechlorination by microwave roasting under the oxygen enriched condition was much more efficient than conventional roasting.