Behavior of Сu, Zn, Pb, As compounds during copper-zinc concentrate and matte comelting in converters

Abstract

The practicability of improving the existing technology of converting copper mattes by comelting with the difficult-toprocess high-sulfur copper-zinc concentrate. The basis for research in the behavior of non-ferrous metals, arsenic and antimony is thermodynamic analysis of the reactions of matte components, converter slag and copper-zinc concentrate interaction in the temperature range 1073–1573 K. The behaviour mechanism of copper, zinc, lead, arsenic, and antimony compounds during co-processing of copper-zinc concentrate with matte is established. High values of the Gibbs free energy of reactions of interaction between oxides of lead and zinc with elemental sulfur, sulfides of non-ferrous metals and iron show the feasibility of the highest possible extraction of lead and zinc into dust in the form of their volatile compounds: sulfides, as well as oxides of lead and zinc in the metallic state in the form of gas. There is shown the possibility of the highest possible extraction of arsenic and antimony into dust by means of converting their nonvolatile pentavalent oxides (As2O5, Sb2O5) into volatile trivalent oxides (As2O3, Sb2O3) and non-toxic sulfides (As2S3, Sb2S3) by the converter slag sulfidizing with the components of copper–zinc concentrate: elemental sulfur and iron sulfide. Direct processing of copper-zinc concentrate in converter allows selective extracting copper into matte as well as lead and zinc into a rich semiproduct suitable for their extraction by existing technologies. It is shown that a significant quality improvement of the resulting converter slag and blister copper is achieved by the high sublimation of arsenic and antimony into dust under conditions of converting copper-lead mattes together with a high-sulfur concentrate.