Dissolution and Solubility of the Erythrite/Annabergite Solid Solution [(CoxNi1-x)3(AsO4)2•8H2O] at 25 ºC

Wang, Xiaoming; Zhang, Xuehong; Zhu, Yinian; Wei, Caichun; Liu, Jie

doi:10.14233/ajchem.2013.14571

Cited by 7 publications

(12 citation statements)

References 25 publications

(58 reference statements)

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“…In both cases, the gels are thought to be precursors or companions to tungstite (WO 3 ⋅H 2 O), hydrotungstite (WO 3 ⋅2H 2 O) and related minerals. Wei et al (2013) noted that vigorous stirring of the starting solutions "was important to suppress the formation of gelatinous, poorly crystallized arsenate phase" during the synthesis of annabergite [Ni 3 (AsO 4 ) 2 ⋅8H 2 O] and erythrite [Co 3 (AsO 4 ) 2 ⋅8H 2 O].…”

Section: Crystallisation From Gelsmentioning

confidence: 99%

Processes of metastable-mineral formation in oxidation zones and mine waste

Majzlan

2020

MinMag

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Oxidation zones and mine wastes are metal-rich, near-surface environments, natural and man-made critical zones of ore deposits, respectively. They contain a number of minerals which, despite their metastability, occur consistently and in abundance. Field studies, presented as examples in this work, show that metastable minerals form not only directly from aqueous solutions, but also from more complex precursors, such as nanoparticles, gels, X-ray amorphous solids, or clusters. Initial precipitation of metastable phases and their conversion to stable phases is described by the Ostwald's step rule. Thermodynamic data show that there is a tendency, but no rule, that structurally more complex phases are also thermodynamically more stable. The Ostwald's step rule could then state that the initial metastable phases are structurally simple and easily assembled from aqueous solutions, nanoparticles, gels, disordered solids, or clusters. The structural similarity of the precursor and the forming phase is a kinetic factor favouring the crystallisation of the new phase. Calculation of saturation indices for mine drainage solutions show that they are mostly supersaturated with respect to the stable phases and the aqueous concentrations are sufficient to precipitate metastable minerals. In our fieldwork, we often encounter gelatinous substances with copper, manganese or tungsten that slowly convert to metastable oxysalt minerals. Another possibility is the crystallisation of various metastable minerals from solid, homogeneous ‘resins’ that are X-ray amorphous. Minerals typical for near-surface environments may be stabilised by their surface energy at high specific surface areas. For example, ferrihydrite is often described as a metastable phase but can be shown to be stable with respect to nanosised hematite.

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Section: Crystallisation From Gelsmentioning

confidence: 99%

Processes of metastable-mineral formation in oxidation zones and mine waste

Majzlan

2020

MinMag

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“…Thermodynamic measurements of the vivianite-group arsenates were made mostly by solubility determinations (Chukhlantsev, 1956;Charykova et al, 2013;Wei et al, 2013;Zhu et al, 2013). Many of these studies suffered from incongruent dissolution of the studied solids.…”

Section: Structure and Crystal Chemistry Of The Vivianite-group Mineralsmentioning

confidence: 99%

“…Many of these studies suffered from incongruent dissolution of the studied solids. Wei et al (2013) wrote that "the release of cobalt or nickel into the bulk solution was always less when compared with release of arsenate". On the other hand, Charykova et al (2013) wrote that the "As content is systematically underestimated with regard to cobalt and nickel in all analyzed solutions".…”

Section: Structure and Crystal Chemistry Of The Vivianite-group Mineralsmentioning

confidence: 99%

Thermodynamics of vivianite-group arsenates M₃(AsO₄)₂ ⋅ 8H₂O (M is Ni, Co, Mg, Zn, Cu) and chemical variability in the natural arsenates of this group

Majzlan,

Reichstein,

Haase

et al. 2024

Eur. J. Mineral.

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Abstract. In this work, we investigated the M3(AsO4)2⋅ 8H2O end members annabergite (M is Ni), erythrite (M is Co), and hörnesite (M is Mg) and their solid solutions. Acid-solution calorimetry and relaxation calorimetry were used to determine the solubility products (log Ksp) for annabergite (−33.7), erythrite (−32.1), and hörnesite (−22.3). Solubility products for other end members of this group were extracted from the literature and critically evaluated. The enthalpies of mixing are complex, related to subsystems M(1)3(AsO4)2⋅ 8H2O–M(1)M(2)2(AsO4)2⋅ 8H2O and M(1)M(2)2(AsO4)2⋅ 8H2O–M(2)3(AsO4)2⋅ 8H2O. They are small and positive for the annabergite–erythrite solid solution and small and negative for the annabergite–hörnesite solid solution. Autocorrelation analysis of Fourier-transform infrared (FTIR) spectra shows correlation of strain decrease in the structure with the negative enthalpies of mixing in the annabergite–hörnesite solid solution. A set of more than 600 electron microprobe analyses of the M3(AsO4)2⋅ 8H2O minerals documents the variability and complexity in this group. Most common compositions are those dominated by Ni, Co, or Ni–Co. The analytical results were used to calculate the maximal configurational entropies which could be a factor that compensates for the small enthalpies of mixing in the annabergite–erythrite solid solution. The data presented here can be used to model sites polluted with metals and arsenic and to enhance our understanding of complex solid solutions.

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“…This finding is in accordance with the solubility studies of erythrite and köttigite. Erythrite is less soluble (solubility constant: Ksp = 10 -34.02 [15]) than köttigite (Ksp = 10 -32.40 [23]). Moreover, whereas erythrite is stable in a near-neutral pH range (pH 5-8) [24], köttigite requires an acidic environment (pH < 3) for stability [25].…”

Section: Minerals 2020 10 X For Peer Review 8 Of 24mentioning

confidence: 99%

“…While reports on the occurrence of limited solid solutions within the arsenate series minerals are frequent [5,[9][10][11][12], no complete or extended solid solutions have been observed as yet in natural samples. Experiments involving syntheses showed a complete solid solution for the erythrite-annabergite binary [13][14][15] and a continuous solid solution for the erythrite-annabergite-hörnesite ternary up to the experimental limits [13].…”

Section: Introductionmentioning

confidence: 99%

Crystal Chemistry of an Erythrite-Köttigite Solid Solution (Co3–xZnx) (AsO4)2·8H2O

et al. 2020

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A wide compositional range, covering about 90% of an expected erythrite-köttigite substitutional solid solution with extreme compositions of (Co2.84Mg0.14Zn0.02) (AsO4)2·8H2O and (Zn2.74Co0.27) (AsO4)2·8H2O, was revealed in a suite of samples from a polymetallic ore deposit in Miedzianka, SW Poland. Members of the solid solution series were examined by means of Electron Probe Microanalysis (EPMA), Scanning Electron Microscopy (SEM)/Energy-Dispersive Spectrometer (EDS), X-ray single-crystal and powder diffraction, and Raman spectroscopy. Metal cations were randomly distributed between two special octahedral sites in the erythrite–köttigite structure. In response to Co ↔ Zn substitutions, small but significant changes in bond distances (particularly in [AsO4] tetrahedra), rotation, and distortion of co-ordination polyhedra were observed. Two sub-series of dominant cationic substitutions (Co-Mg-Ni and Co-Fe-Zn) were noted within the arsenate series of vivianite-group minerals linked by erythrite. The paragenetic sequence erythrite → Zn-rich erythrite → Co-rich köttigite → köttigite reflects the evolution of the solution’s pH towards increased acidity and a relative increase in the concentration of Zn ions following precipitation of erythrite.

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Dissolution and Solubility of the Erythrite/Annabergite Solid Solution [(CoxNi1-x)3(AsO4)2•8H2O] at 25 ºC

Cited by 7 publications

References 25 publications

Processes of metastable-mineral formation in oxidation zones and mine waste

Processes of metastable-mineral formation in oxidation zones and mine waste

Thermodynamics of vivianite-group arsenates M₃(AsO₄)₂ ⋅ 8H₂O (M is Ni, Co, Mg, Zn, Cu) and chemical variability in the natural arsenates of this group

Crystal Chemistry of an Erythrite-Köttigite Solid Solution (Co3–xZnx) (AsO4)2·8H2O

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Dissolution and Solubility of the Erythrite/Annabergite Solid Solution [(CoxNi1-x)3(AsO4)2•8H2O] at 25 ºC

Cited by 7 publications

References 25 publications

Processes of metastable-mineral formation in oxidation zones and mine waste

Processes of metastable-mineral formation in oxidation zones and mine waste

Thermodynamics of vivianite-group arsenates M3(AsO4)2 ⋅ 8H2O (M is Ni, Co, Mg, Zn, Cu) and chemical variability in the natural arsenates of this group

Crystal Chemistry of an Erythrite-Köttigite Solid Solution (Co3–xZnx) (AsO4)2·8H2O

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Thermodynamics of vivianite-group arsenates M₃(AsO₄)₂ ⋅ 8H₂O (M is Ni, Co, Mg, Zn, Cu) and chemical variability in the natural arsenates of this group