Thermodynamics of Arsenates, Selenites, and Sulphates in the Oxidation Zone of Sulfide Ores. XVI. Solubility of the Synthetic Analogue of Mandarinoite at 25°C

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2024年12月1日

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M. V. Charykova,
K. L. Ushakova,
A. Holzheid,
V. G. Krivovichev,
N. M. Efimenko,
N. V. Platonova

摘要

Abstract

This study aims to synthesize two iron(III) selenites—Fe₂(SeO₃)₃·5H₂O (analogous to the mineral mandarinoite) and Fe₂(SeO₃)₃·3H₂O—and to investigate their solubility. The obtained samples were identified by powder X-ray diffraction and energy-dispersive X-ray microanalysis. Solubility was determined through the method of isothermal saturation at 25°C. To suppress the hydrolysis of Fe³⁺ ions and prevent the precipitation of iron hydroxide, the experiments were conducted in nitric- or sulfuric-acid solutions. The compositions of the saturated solutions were used to calculate the solubility product using a Geochemist’s Workbench (GMB 9.0, SpecE8 program). The calculated values of the solubility product are log K_sp(Fe₂(SeO₃)₃·5H₂O) = –38.6 ± 0.5 and log K_sp(Fe₂(SeO₃)₃·3H₂O) = –39.0 ± 0.2.