Thermodynamic properties and stoichiometry of As (III) hydroxide complexes at hydrothermal conditions

Pokrovski, Gleb S.; Gout, Robert; Schott, Jacques; Зотов, А. В.; Harrichoury, Jean-Claude

doi:10.1016/0016-7037(95)00427-0

Cited by 165 publications

(93 citation statements)

References 38 publications

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“…Fleet and Mumin (1997) suggested, based on observations of fine-grained experimental runs, that precipitation of Au-rich arsenian pyrite is a kinetically-favoured and surface-controlled phenomenon resulting in As reduction. For example, sorption of the dominant dissolved As-species As 3+ (OH) 3 (Pokrovski et al, 1996) under ambient conditions results in reduction of As 3+ to As 1-in the pyrite structure with local formation of a FeAsS-like precipitate (Bostick and Fendorf, 2003). Also, experimental data show that reaction paths involved in the formation of arsenian pyrite and speciation of As in its structure depend on the type or nature of the initial mineral nucleus (Fleet and Mumin, 1997;Qian et al, 2012).…”

Section: Arsenic Solubility and Speciationmentioning

confidence: 99%

The coupled geochemistry of Au and As in pyrite from hydrothermal ore deposits

Deditius¹,

Reich²,

Kesler³

et al. 2014

Geochimica et Cosmochimica Acta

471

205

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The ubiquity of Au-bearing arsenian pyrite in hydrothermal ore deposits suggests that the coupled geochemical behaviour of Au and As in this sulfide occurs under a wide range of physico-chemical conditions. Despite significant advances in the last 20 years, fundamental factors controlling Au and As ratios in pyrite from ore deposits remain poorly known. Here we explore these constraints using new and previously published EMPA, LA-ICP-MS, SIMS, and μ-PIXE analyses of As and Au in pyrite from Carlin-type Au, epithermal Au,

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Section: Arsenic Solubility and Speciationmentioning

confidence: 99%

The coupled geochemistry of Au and As in pyrite from hydrothermal ore deposits

Deditius¹,

Reich²,

Kesler³

et al. 2014

Geochimica et Cosmochimica Acta

471

205

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“…Superimposed predominance diagrams for the Fe±S± K±CO 2 ±H 2 ±O 2 system (after Nordstrom and Munoz (1994)), and for the As±H 2 ±O 2 system as a function of pH and pE at 258C, 1 bar. Arsenic speciation (solid phases not shown) from thermodynamic data in Bowell (1994), Cherry et al (1979), Pokrovsky et al (1996) and Hem (1977 minerals and predominance ®elds for aqueous Fe species in the system Fe±S±K±CO 2 ±H 2 ±O 2 ; predominance ®elds for aqueous As species are superimposed on the Fe diagram. Both ferrihydrite, a precursor to goethite (Schwertmann and Fischer, 1973;Schwertmann et al, 1985), and jarosite are common weathering products of pyrite.…”

Section: Arsenic Distribution In Secondary Phasesmentioning

confidence: 99%

Arsenic speciation in pyrite and secondary weathering phases, Mother Lode Gold District, Tuolumne County, California

Savage

Tingle

O’Day

et al. 2000

Applied Geochemistry

381

126

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Arsenian pyrite, formed during Cretaceous gold mineralization, is the primary source of As along the Melones fault zone in the southern Mother Lode Gold District of California. Mine tailings and associated weathering products from partially submerged inactive gold mines at Don Pedro Reservoir, on the Tuolumne River, contain H20±1300 ppm As. The highest concentrations are in weathering crusts from the Clio mine and nearby outcrops which contain goethite or jarosite. As is concentrated up to 2150 ppm in the ®ne-grained (<63 mm) fraction of these Fe-rich weathering products.Individual pyrite grains in albite-chlorite schists of the Clio mine tailings contain an average of 1.2 wt.% As. Pyrite grains are coarsely zoned, with local As concentrations ranging from H0 to 5 wt.%. Electron microprobe, transmission electron microscope, and extended X-ray absorption ®ne-structure spectroscopy (EXAFS) analyses indicate that As substitutes for S in pyrite and is not present as inclusions of arsenopyrite or other As-bearing phases. Comparison with simulated EXAFS spectra demonstrates that As atoms are locally clustered in the pyrite lattice and that the unit cell of arsenian pyrite is expanded by H2.6% relative to pure pyrite. During weathering, clustered substitution of As into pyrite may be responsible for accelerating oxidation, hydrolysis, and dissolution of arsenian pyrite relative to pure pyrite in weathered tailings. Arsenic K-edge EXAFS analysis of the ®ne-grained Ferich weathering products are consistent with corner-sharing between As(V) tetrahedra and Fe(III)-octahedra. Determinations of nearest-neighbor distances and atomic identities, generated from least-squares ®tting algorithms to spectral data, indicate that arsenate tetrahedra are sorbed on goethite mineral surfaces but substitute for SO 4 in jarosite. Erosional transport of As-bearing goethite and jarosite to Don Pedro Reservoir increases the potential for As mobility and bioavailability by desorption or dissolution. Both the substrate minerals and dissolved As species are expected to respond to seasonal changes in lake chemistry caused by thermal strati®cation and turnover within the monomictic Don Pedro Reservoir. Arsenic is predicted to be most bioavailable and toxic in the reservoir's summer hypolimnion. 7

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“…9. Pokrovski et al (1996); 10. Flis et al (2007), 0 T P r r S , recalculated using elemental data from NIST; 11.…”

Section: C223 Derivation Of Thermodynamic Properties Of Arsenic Solmentioning

confidence: 99%

Research Project on CO2 Geological Storage and Groundwater Resources: Water Quality Effects Caused by CO2 Intrusion into Shallow Groundwater

Birkhölzer¹,

Apps²,

Zheng³

et al. 2008

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Thermodynamic properties and stoichiometry of As (III) hydroxide complexes at hydrothermal conditions

Cited by 165 publications

References 38 publications

The coupled geochemistry of Au and As in pyrite from hydrothermal ore deposits

The coupled geochemistry of Au and As in pyrite from hydrothermal ore deposits

Arsenic speciation in pyrite and secondary weathering phases, Mother Lode Gold District, Tuolumne County, California

Research Project on CO2 Geological Storage and Groundwater Resources: Water Quality Effects Caused by CO2 Intrusion into Shallow Groundwater

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