Experimental study of silicates phosphatization in conditions of the supergene zone (hornblende, orthoclase, labrador)

Experimental verification of the hypothesis of silicates phosphatization in conditions of the supergene zone was carried out. In addition to previous experiments with clay minerals (kaolinite and montmorillonite), phosphatization of aluminosilicates of other structural types (hornblende, orthoclase, and labrador), which for 9 months interacted with 1.2–6.0 mM orthophosphate solutions over a wide range of acidity, was studied. The existence of common for all minerals close to the linear dependence between changes in the concentrations of phosphorus and silicon in solution Δ[Si] ≈ –Δ[P]. is ascertained. The possibility of aluminosilicates substitution with phosphate minerals at relatively low concentrations of dissolved phosphorus, corresponding to the phosphate content in soil solutions, is proved.

Supergene gold transformation in technogenic mineral formations

This article is about the research on gold obtained from mine wastes and other technogenic mineral formations. The authors investigated how solid phases of gold in supergene zone transform from various deposits. Results show the following supergene gold transformations by various physical, chemical, biological and mechanical processes occurring in the wastes. Transformations result in changes in morphology and chemical composition, and special redistribution of gold in wastes.

Chemical composition and formation conditions of NaHCO3 type of waters in the eastern Transbaikalia

The chemical composition of the supergene zone groundwater in the Eastern Transbaikalia is considered. The main geochemical processes for steppe landscapes are identified and determined the causes of some component’s concentrations in groundwater. To understand the formation conditions of NaHCO3 water, were calculated equilibria of this water with the main minerals of the region’s rocks.

Stabilities of byströmite, MgSb2O6, ordoñezite, ZnSb2O6 and rosiaite, PbSb2O6, and their possible roles in limiting antimony mobility in the supergene zone

In order to clarify the roles that secondary minerals may have in determining the extent of dispersion of Sb in the supergene environment, syntheses and stability studies of the Sb(V) oxides byströmite, MgSb2O6, ordoñezite, ZnSb2O6 and rosiaite, PbSb2O6, have been undertaken. Solubilities in aqueous HNO3 were determined at 298.2 K and the data obtained used to calculate values of Δ at the same temperature. The derived Δ(s, 298.2 K) values for MgSb2O6 (–1554.1 ±3.6 kJ mol–1), ZnSb2O6 (–1257.0 ±2.6 kJ mol–1) and PbSb2O6 (–1154.2 ±2.6 kJ mol–1) have been used in subsequent calculations to determine their relative stabilities and relationships with other secondary Sb minerals.