Abstract
Copper-bearing dross generated in lead metal smelting operations is composed of very complex compounds which include Pb, Sn and Sb. The presence of these elements makes the dross difficult to process. The copper compounds also include valuable metals and rare earth elements, therefore an efficient refining technology is required. In previous works, we have shown that evaluating the dross phases by using both fast Silicon drift detector technology (Thermo Scientific UltraDry) and multivariate statistical component analysis (Thermo Scientific COMPASS) is very effective. In this work, we investigated the refining heat treatment conditions in the process of the copper-bearing dross. The results of the COMPASS phase analysis showed that a Cu-Sn alloy was the main copper-bearing phase generated in the dross when small amounts of oxygen were introduced during the heat treatment process. Conversely, under high oxygen conditions during the process CuO is generated as the principal copper-bearing dross component. The leaching rate of Cu was about 50% after sulfuric acid leaching for the unprocessed dross. The leaching rate of Cu increased to more than 95% for the processed dross in which the principal component was CuO. Using these analysis results, we were able to rapidly and accurately determine the efficiency improvement of the copper refining process.
