A THERMODYNAMIC MODEL OF CHEMICAL WEATHERING OF WASTE FROM FLOTATION ENRICHMENT OF SULFIDE PGE–Cu–Ni ORES
S.I. Starostina1,2, O.L. Gaskova2, N.V. Yurkevich2,3
1Trofimuk Institute of Petroleum Geology and Geophysics Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia
2V.S. Sobolev Institute of Geology and Mineralogy Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia
3Peoples' Friendship University of Russia named after Patrice Lumumba, Moscow, Russia
Keywords: Thermodynamic modeling, wastes of flotation enrichment, sulphide ores, alternate resources.
Abstract
A thermodynamic model of the interaction between surface waters and the wastes of flotation enrichment of sulfide PGE–Cu–Ni ores from the ore region under consideration (Krasnoyarsk krai) is presented. The relevance of the study is determined by the need to assess the long-term stability of mineral associations. The aim of the work is to establish the patterns of transformation of mineral associations during long-term storage. The initial information was provided by mineralogical and chemical composition of samples from two pits, as well as the chemical composition of water extracts [Starostina et al., 2025]. Calculations were carried out in the solid–water–gas system under variations of Eh, simulating different degrees of system openness to atmospheric oxygen (standard T–P, pCO2(gas)
= 10–3.5 atm). Based on the modeling results, it was found that pyrrhotite is stable under extremely reducing conditions (pO2(gas) = 10–79 atm), where the dissociation of water into atomic oxygen and hydrogen may occur. In general, the obtained models reflect the transition from sulfide to oxide–silicate associations with a decrease in the number of mineral phases as oxidation progresses. The modeled associations correspond well with mineral parageneses observed in polished sections. It was shown that the material retains its primary mineral structure even after decades of storage, which is explained by the high content of rock-forming minerals within a dense clay matrix that prevents oxygen and moisture from penetrating in amounts sufficient for intensive oxidation. The results obtained are recommended for use in the development of technological schemes for the recovery of potentially valuable metals from the flotation wastes of sulfide PGE–Cu–Ni ores.
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