Mechanochemical treatment to remove arsenic from copper ore

Abstract

This study tested the removal of arsenic from copper ore concentrate via a mechanochemical treatment by planetary ball milling. The harmful components of ore, such as arsenic, are increasing year by year and decreasing the copper grade, therefore there is a strong need to improve the separation of arsenic from copper ore. The effect of grinding as a result of chemical activation caused by mechanochemical treatment was evaluated by XRD and X-ray absorption spectroscopy (XAS) measurements. From the results of the XRD analysis, several crystalline minerals were identified from the original samples. The diffraction peaks of the original samples were reduced by grinding, although grinding did not generate any new diffraction peaks. The comparison of the results of grinding in dry and wet conditions showed that the rate of disappearance of the crystalline minerals was faster in dry grinding than in wet grinding. To clarify the chemical state of arsenic in copper ore, XAS analysis was carried out. The results indicated that the arsenic compound changed from sulfide, in the original sample, to oxide after grinding. As a result of oxidation, the arsenic was easy to dissolve in a water and alkaline solution, and optimized dry and wet grinding conditions achieved up to 76% arsenic removal efficiency.