Thermodynamic model for acidic Fe(II) sulphate from solubility data

Kobylin, Petri; Sippola, Hannu; Taskinen, Pekka

doi:10.1016/j.calphad.2012.06.011

Cited by 15 publications

(6 citation statements)

References 28 publications

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“…The in situ formation of kieserite from high Mg-content (14.1%) saprolite ore and its dissolution behavior have also been demonstrated by X-ray diffraction studies [61]. There is also potential for kieserite-szomolnokite (MgSO4.H2O-FeSO4.H2O) solid solutions [62] to form during the current tests since the solubility of ferrous sulfate in sulfuric acid is of similar magnitude to nickel sulfate at high temperatures [63]. However, as the concentration of ferrous sulfate does not remain high due to ferrous iron oxidation, the following discussion is focused mainly on the nickel and magnesium sulfate concentrations of co-processing leach liquor.…”

Section: Divalent Metal Sulfate Solubilitymentioning

confidence: 61%

The High Temperature Co-Processing of Nickel Sulfide and Nickel Laterite Sources

McDonald

2020

Minerals

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The pressure oxidation of low-grade nickel sulfide concentrate with high iron sulfides content generates significant amounts of sulfuric acid that must be neutralized. This acid can be utilized to leach metal values from ores such as nickel laterites. The present study demonstrates the use of a low-grade nickel concentrate generated from Poseidon Nickel Mt Windarra ore to enable additional nickel and cobalt extraction from a Bulong Nickel Operation nickel laterite blend. The co-processing of these materials at 250 °C, with oxygen overpressure, using total pulp densities of 30% or 40% w/w, and a range of nickel concentrate to nickel laterite mass ratios between 0.30–0.53, yielded base metal extractions of 95% or greater. The final free acid range was between 21.5–58.5 g/L, which indicates that enough in situ sulfuric acid was generated during co-processing. The acid was shown from mineralogical analysis to be efficiently utilized to dissolve the laterite ore, which indicates that the primary iron hydrolysis product was hematite, while the aluminum-rich sodium alunite/jarosite phase that formed hosts approximately 5% of the hydrolyzed iron.

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Section: Divalent Metal Sulfate Solubilitymentioning

confidence: 61%

The High Temperature Co-Processing of Nickel Sulfide and Nickel Laterite Sources

McDonald

2020

Minerals

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“…Aqueous mixtures of sulfuric acid and metal sulfates are not only relevant for "acid mine drainage" (or other situations where sulfides oxidize in natural environments), but also for acid pressure leaching of latertites or oxidative leaching of sulfide ores. Kobylin [19][20][21]. Combined with a Pitzer model for the Zn 2+ −H + −SO 4 2− −H 2 O system [22], the solubility of Ni (1-x) Zn x SO 4 ؒ7H 2 O will be predicted and compared with experimental data [23].…”

Section: Stable Solubility Equilibriamentioning

confidence: 99%

Solid-solute phase equilibria in aqueous solution: Fundamentals and applications

Königsberger¹

2013

Pure and Applied Chemistry

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Carbonates 1 Phase Transitions 1 Solutions 1 ThermodynamicsSolid binary carbonate phases often dissolve congruently in aqueous media, even when they are not stable under the prevailing conditions. From the thermodynamic point of view these dissolution reactions lead to a metastable equilibrium with fixed composition, when neither diffusion in the solid state nor recrystallization from the solution occurs. The solubility of natural huntite, CaMg3(C03)4, was studied potentiometrically at 50°C and I = 3.0 mol kg-' (Na)C104. Since it dissolved congruently the solubility constant log * . Amazingly enough phase equilibria of solid mixtures in aqueous media have seldom been studied in detail, although the corresponding reactions play an important role in geochemistry as well as in hydrometallurgy. Lippmann [S] described the aqueous solubility of binary mineral systems using the total solubility product and the mole fraction as master variables of phase diagrams. These diagrams are based on the solubility products of the pure end members and a simple electrostatic mixing model, but have in most cases not been verified experimentally. One of the reasons for this lack of scientific activity in an obviously interesting field is certainly the fact that the rates of heterogeneous ionic reactions are rather slow at temperatures between the freezing and the boiling point of water at ordinary pressure, and differing results have been obtained when equilibrium was approached from undersaturation and supersaturation respectively. A pertinent example are the contradictory results for the solubilities of magnesian calcites obtained by different research groups [6].In this paper the thermodynamic formalism for solid-solute ionic equilibria in the system CaC03 -MgC03 -H,O is presented with particular emphasis on phase transitions without diffusion in the solid state [7]. It is applied for the determination of the solubility constant, phase equilibria and free enthalpy of formation of huntite, CaMg3(CO&. This mineral occurs naturally although its decomposition into dolomite, CaMg(CO&, and magnesite, MgC03, is thermodynamically favoured.

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“…nH 2 O in sulfuric acid media. The number of molecules of water in the hydrate structure (n) strongly depends on the concentration of H 2 SO 4 and on the temperature [26], with, for instance, n =1, 4, 5, 6 or 7 for M = Fe (II) [27], n = 1, 3 or 5 for M = Cu (II) [26] and n =1, 4, 6, 7 for M = Zn (II) [28]. In the case of vanadium, it is usually admitted that V (V) precipitates in its oxide form V 2 O 5 [29] while V (IV) , V (III) and V (II) form sulfate salts, respectively VOSO 4 ,V 2 (SO 4 ) 3 and VSO 4 [14].…”

Section: Aging and Precipitation Of Vanadium Supersaturated Electrolytementioning

confidence: 99%

Stability of highly supersaturated vanadium electrolyte solution and characterization of precipitated phases for vanadium redox flow battery

Carvalho

Cassayre²,

Quaranta³

et al. 2021

Journal of Energy Chemistry

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The vanadium redox flow battery (VRFB) has been receiving great attention in recent years as one of the most viable energy storage technologies for large-scale applications. However, higher concentrations of vanadium species are required in the H 2 O-H 2 SO 4 electrolyte in order to improve the VRFB energy density. This might lead to unwanted precipitation of vanadium compounds, whose nature has not been accurately characterized yet. For this purpose, this study reports the preparation of V (II) ,V (III) ,V (IV) and V (V) supersaturated solutions in a 5 M H 2 SO 4 -H 2 O electrolyte by an electrolytic method, from the only vanadium sulfate compound commercially available (VOSO 4 ). The precipitates obtained by ageing of the stirred solutions are representative of the solids that may form in a VRFB operated with such supersaturated solutions. The solid phases are identified using thermogravimetric analysis, X-ray diffraction and SEM. We report that dissolved V (II) ,V (III) and V (IV) species precipitate as crystals of VSO 4 ,V 2 (SO 4 ) 3 and VOSO 4 hydrates and not in their anhydrous form; conversely V (V) precipitates as an amorphous V 2 O 5 oxide partially hydrated. The measured hydration degrees (respectively 1.5, 9, 3 and 0.26 mol of H 2 O per mol of compound) might significantly affect the overall engineering of VRFB operating with high vanadium concentrations.

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Thermodynamic model for acidic Fe(II) sulphate from solubility data

Cited by 15 publications

References 28 publications

The High Temperature Co-Processing of Nickel Sulfide and Nickel Laterite Sources

The High Temperature Co-Processing of Nickel Sulfide and Nickel Laterite Sources

Solid-solute phase equilibria in aqueous solution: Fundamentals and applications

Stability of highly supersaturated vanadium electrolyte solution and characterization of precipitated phases for vanadium redox flow battery

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