The thermodynamics of arsenates, selenites, and sulfates in the oxidation zone of sulfide ores. XI. Solubility of synthetic chalcomenite analog and zinc selenite at 25°C

Charykova, M. V.; Кривовичев, В. Г.; Иванова, Н. М.; Semenova, V. V.

doi:10.1134/s1075701515080036

Cited by 6 publications

(3 citation statements)

References 12 publications

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“…As shown previously, the stability of hydrous selenites of cobalt (cobaltomenite CoSeO3•2H2O) [3], nickel (ahlfeldite, NiSeO3•2H2O) [3], zinc (ZnSeO3•2H2O and ZnSeO3•H2O) [5,27] and cadmium (CdSeO3•H2O) [5,28] correspond to the conditions of mandarinoite formation, with the only difference that mandarinoite crystallized in a more wide range of pH values. It should be noted that zinc and cadmium selenites have not yet been found in in the oxidation zone of sulfide and selenide ores because, in our opinion, diagnostics are partly hampered: Zn and Cd (in contrast to Cu, Co, Ni, and Fe) are not chromophores and therefore their salts are colorless or white.…”

Section: Stability Of Mandarinoite In the Oxidation Zonesupporting

confidence: 64%

A Calorimetric and Thermodynamic Investigation of the Synthetic Analogue of Mandarinoite, Fe2(SeO3)3·5H2O

et al. 2018

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Thermophysical and thermochemical calorimetric investigations were carried out on the synthetic analogue of mandarinoite. The low-temperature heat capacity of Fe2(SeO3)3∙5H2O(cr) was measured using adiabatic calorimetry between 5.3 and 324.8 K, and the third-law entropy was determined. Using these Cp,mo(T) data, the third law entropy at T = 298.15 K, Smo, is calculated as 520.1 ± 1.1 J∙K–1∙mol–1. Smoothed Cp,moT values between T → 0 K and 320 K are presented, along with values for Smo and the functions [HmoT-Hmo0] and [ΦmoT-Φmo0]. The enthalpy of formation of Fe2(SeO3)3∙5H2O(cr) was determined by solution calorimetry with HF solution as the solvent, giving ΔfHmo(298 К, Fe2(SeO3)3∙5H2O, cr) = –3124.6 ± 5.3 kJ/mol. The standard Gibbs energy of formation for Fe2(SeO3)3∙5H2O(cr) at T = 298 K can be calculated on the basis on ΔfHmo(298 К) and ΔfSmo(298 К): ΔfGmo(298 К, Fe2(SeO3)3∙5H2O, cr) = ‒2600.8 ± 5.4 kJ/mol. The value of ΔfGm for Fe2(SeO3)3·5H2O(cr) was used to calculate the Eh–pH diagram of the Fe–Se–H2O system. This diagram has been constructed for the average contents of these elements in acidic waters of the oxidation zones of sulfide deposits. The behaviors of selenium and iron in the surface environment have been quantitatively explained by variations of the redox potential and the acidity-basicity of the mineral-forming medium. These parameters precisely determine the migration ability of selenium compounds and its precipitation in the form of solid phases.

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Section: Stability Of Mandarinoite In the Oxidation Zonesupporting

confidence: 64%

A Calorimetric and Thermodynamic Investigation of the Synthetic Analogue of Mandarinoite, Fe2(SeO3)3·5H2O

et al. 2018

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“…Chalcomenite is the more abundant mineral; clinochalcomenite is poorly documented and remains a controversial mineral species. The thermal stability, the solubility and thermochemical calorimetric investigations were carried out on a synthetic analogue of chalcomenite [17,54,55].…”

Section: Thermodynamic System Cu-se-h2omentioning

confidence: 99%

“…The solubility and the thermal behavior of synthetic ZnSeO3·2H2O, and ZnSeO3·H2O were discussed in [55,57]. It was shown that ZnSeO3·2H2O is a more stable phase than ZnSeO3·H2O under environmental conditions.…”

Section: Thermodynamic System Zn-se-h2omentioning

confidence: 99%

The Thermodynamics of Selenium Minerals in Near-Surface Environments

2017

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Selenium compounds are relatively rare as minerals; there are presently only 118 known mineral species. This work is intended to codify and systematize the data of mineral systems and the thermodynamics of selenium minerals, which are unstable (selenides) or formed in near-surface environments (selenites), where the behavior of selenium is controlled by variations of the redox potential and the acidity of solutions at low temperatures and pressures. These parameters determine the migration of selenium and its precipitation as various solid phases. All selenium minerals are divided into four groups-native selenium, oxide, selenides, and oxysalts-anhydrous selenites (I) and hydrous selenites and selenates (II). Within each of the groups, minerals are codified according to the minimum number of independent elements necessary to define the composition of the mineral system. Eh-pH diagrams were calculated and plotted using the Geochemist's Workbench (GMB 9.0) software package. The Eh-pH diagrams of the Me-Se-H 2 O systems (where Me = Co, Ni, Fe, Cu, Pb, Zn, Cd, Hg, Ag, Bi, As, Sb, Al and Ca) were plotted for the average contents of these elements in acidic waters in the oxidation zones of sulfide deposits. The possibility of the formation of Zn, Cd, Ag and Hg selenites under natural oxidation conditions in near surface environments is discussed.

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Mineral systems and the thermodynamics of selenites and selenates in the oxidation zone of sulfide ores – a review

Charykova

Кривовичев

2016

Miner Petrol

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The thermodynamics of arsenates, selenites, and sulfates in the oxidation zone of sulfide ores. XI. Solubility of synthetic chalcomenite analog and zinc selenite at 25°C

Cited by 6 publications

References 12 publications

A Calorimetric and Thermodynamic Investigation of the Synthetic Analogue of Mandarinoite, Fe2(SeO3)3·5H2O

A Calorimetric and Thermodynamic Investigation of the Synthetic Analogue of Mandarinoite, Fe2(SeO3)3·5H2O

The Thermodynamics of Selenium Minerals in Near-Surface Environments

Mineral systems and the thermodynamics of selenites and selenates in the oxidation zone of sulfide ores – a review

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