Characterization of Two Sludges from a Pyrometallurgical Copper Smelting Complex for Designing a Se and Pb Recovery Proposal

Abstract

Gas scrubbing sludge (SS) and fine dust of converters (SC) are wastes generated in the off-gas cleaning system of smelting and converting processes. Both wastes are considered hazardous materials due to their high metal contents and leaching characteristics. The main purpose of this study was to gain essential knowledge on the recovery of valuable elements contained in these wastes. Thus, an exhaustive characterization was carried out to determine the composition, mineral phases, particle size, and leachability of both wastes (SS and SC) as a preliminary step to select the most appropriate applications and treatment for them. These wastes are composed of fine particles (~ 95% < 63 µm), mainly containing Pb (> 20%) as anglesite (PbSO 4), while SS presents a high concentration of Se (34%), which is mainly identified as metallic selenium. Therefore, these residues could be used as secondary sources of Pb and Se. The recovery of Se by roasting process and Pb recovery by hydrometallurgical route seem to be the best options for the management of these wastes.