Eco-friendly and efficient extraction of valuable elements from copper anode mud using an integrated pyro-hydrometallurgical process

Abstract

An integrated pyro-hydrometallurgical process was developed to extract valuable elements from copper anode mud, a hazardous solid waste. Sulfation roasting-water adsorption was first conducted to recover selenium. Then, water leaching-iron powder cementation was adopted to extract copper from the roasted residue. Afterwards, selective chloride leaching-H2C2O4 reduction was employed to extract gold in the copper-leaching residue. Last, sulfite leaching-Na2S2O4 reduction was used to recover silver from the gold-leaching residue, and the barren leachate could be circularly used for silver leaching with the addition of a small quantity of lixiviant. Lead was hardly dissolved during the above treatments and a lead concentrate was finally obtained. 97.0% of selenium, 91.9% of copper, 98.7% of gold, 98.6% of silver and 99.8% of lead in the mud were recovered by this integrated pyro-hydrometallurgical process, and the grades of obtained crude selenium, sponge copper, metallic gold, metallic silver and lead concentrate products reached 93.6%, 86.4%, 99.5%, 96.3% and 52.5%, respectively. This integrated process possesses the advantages of improved environmental friendliness, high recovery rates of valuable elements and low energy consumption and reagent dosage, and thus has a bright prospect in industrial application.