Lead recovery from leaching residues of zinc industry using aliphatic amine

A desulfurization method previously developed for battery paste processing was found efficient for lead recovery from various types of non-ferrous metal industry residues example zinc industry leaching wastes. The hot or super-hot acid leaching (HAL or SHAL) residues of the neutral leaching residues of zinc calcine are either smelted or stockpiled. However, this can be hydrometallurgically processed to extract lead sulphate and enrich residue for further metals recovery. The water solution of triethylenetetramine, which is a powerful, selective extracting agent towards lead sulphate, was used as a leaching medium. The developed technology is the closed loop, almost effluent-free, and satisfies high lead recovery yield around 90%. It allows to lower the energy required for processing leaching residues (in comparison to pyrometallurgy) and emissions of toxic gases (SO₂, CO₂, NO_X). The main product is pure lead carbonate (72% Pb and low amount of impurities) that can be smelted at a much lower temperature than the initial lead sulphate contained in the residue.