Secondary minerals of Fe, Pb, Cu in sulfide-containing tailings: sequence of formation, electrochemical reactions and physico-chemical model (Talmovskie Sands, Salaire, Russia)

Abstract

The results of studies of the composition and form of secondary minerals Fe, Pb, Cu, formed under contrasting physico-chemical conditions of the accumulated tailings from the enrichment of barite-polymetallic ores of the Salair ore field, are presented. The complex mineral composition of ores (pyrite, chalcopyrite, sphalerite, galena, fahlore) and long-term processes of chemical weathering of the substance contributed to the formation of monomineral and zonal secondary rims and fillings of the intergranular space, which were identified using modern research methods. Plumbojarosite, anglesite, cerussite, and iron hydroxides predominate among them; pyromorphite, ginsdalite, and covellite occur less frequently. The method of thermodynamic modeling was used to solve the inverse problem - the restoration of the composition of solutions that led to a change in the associations of secondary minerals. The nature of the ongoing processes can be characterized not only by chemical interactions, but also by electrochemical reactions in the systems under consideration, where various mineral components act as galvanic pairs, which, in combination with the physico-chemical parameters of the medium (pH, Eh, ionic composition of solutions ), leads to stepwise or incomplete oxidation of the original minerals with subsequent selective deposition of secondary compounds.