Sustainable Mining and Metallurgy

The acid leaching solution with high copper content was reduced by iron powder to recover copper. The effects of pH value, temperature, time and iron powder addition on the reduction effect were studied. The SEM-EDS and XRD phase analysis of the generated sponge copper were carried out. The φ pH diagram of Cu-As-Fe-H2O system was drawn by thermodynamic software to study the change of phase in the solution system. The results show that when the reaction temperature is 40℃, the reaction time is about 30min, the amount of iron powder is about 1.1 times of the theoretical amount, and the pH value of the solution is not adjusted, the copper precipitation rate can reach more than 99%, and the content of As and Te impurities in the obtained sponge copper is low. The internal elements of sponge copper are evenly distributed, and its morphology is mainly flocculent. A small amount is similar to the morphology of iron powder, showing irregular polygons. The flocculent is mainly the product of the full reaction of iron powder and copper ions in the leaching solution. The polygonal particles are mainly composed of a small amount of copper, iron, Cu₂O and copper arsenic compounds. Sponge copper is mainly composed of FeCu₄, Cu₂O and Cu₃As.