Firstprinciples calculations of the thermodynamic
Abstract The thermodynamic mixing properties of As into pyrite and marcasite have been investigated using firstprinciples and Monte Carlo calculations in order to understand the incorporation of this important metalloid into solid solution The exchange parameters J for marcasite and pyrite series are presented in Table 2 and indicate that As and S strongly interact at the atomic scale Their magnitude and sign show that ordering in both marcasite and pyrite solid solutions promotes heteroanionic As–S nearestneighbor and 4thnearest neighbor interactions (negative Js) Since there is always an equal number of nearest and second nearest neighbor As–S interactions in arsenian pyrites and marcasites, Firstprinciples calculations of the thermodynamic INTRODUCTION Iron disulfide (FeS2) forms two common polymorphs, pyrite and marcasite From 5700 K marcasite is metastable with respect to pyrite and above 700 K marcasite irreversibly transforms to pyrite (Gronvold and Westrum, 1976) At 29815 K pyrite is more stable by 3901 kj/molEpitaxial overgrowths of marcasite on pyrite from the
Pyrite: Mineral information, data and localities
Pyrite Group The isometric (cubic) polymorph of orthorhombic marcasite Compare UM199743S:Fe Pyrite is a very common mineral (also one of the most common natural sulfides, and the most common disulfide ), found in a wide variety of geological formations from sedimentary deposits to hydrothermal veins and as a constituent of metamorphic rocks pyrite may represent mixing of pyrite with fi ne layers of arsenopyrite or marcasitetype phases, and that the gold is structurally bound in the latter as Au+ and Au0 Another important consideration is that models of traceelement incorporation in pyrite have been based on studies of samples from mineral deposits (sediCRYSTALLOGRAPHIC CONTROLS ON TRACEELEMENT Based on the assumption that arsenic substitutes for sulphur they studied by firstprinciples and Monte Carlo methods the solubility of arsenic in pyrite and marcasite They found that up to 6 wt% of arsenic can be incorporated in solid solution in pyrite while beyond this concentration, arsenic segregates into arsenopyrite domainsArsenic incorporation into FeS2 pyrite and its
(PDF) Mechanisms of sedimentary pyrite formation
Incorporation of ImpuritiesElemental analyses of natural pyrite or marcasite often show that iron disulfi des contain signifi cant amounts of heavy metals (eg, Ni, Cu, Co, Hg) and metalloids (see Table 2) The utilization of waste from marcasite jewelry production as pyrite FeS 2 source incorporated with commercial TiO 2 as a photocatalyst composite material for lignin degradation has a potential The TiO 2 particles were attached on the surface of waste particles by physical bonds to form the core/shell microparticles by simple methodPossible use of waste from marcasite jewelry industry Revised version, 10 August 2006 Arsenic incorporation into FeS2 pyrite and its influence on dissolution: a DFT study Marc Blancharda, Kate Wrightb, C Richard A Catlowa a Royal Institution of Great Britain, 21 Albemarle Street, London W1S 4BS, UK b Nanochemistry Research Institute, Department of Applied Chemistry, Curtin University of Technology, PO Box U1987, Perth 6845, Arsenic incorporation into FeS2 pyrite and its influence
Trace Element Signatures in Pyrite and Marcasite From
In addition, crystal structures may also play an important role in the incorporation of trace elements into pyrite and marcasite (Deditius and Reich, 2016; Keith et al, 2018a) Marcasite is a polymorph of pyrite and isostructural with arsenopyrite, which leads to a higher capacity of the orthorhombic marcasite lattice to host As compared to pyrite may represent mixing of pyrite with fi ne layers of arsenopyrite or marcasitetype phases, and that the gold is structurally bound in the latter as Au+ and Au0 Another important consideration is that models of traceelement incorporation in pyrite have been based on studies of samples from mineral deposits (sediCRYSTALLOGRAPHIC CONTROLS ON TRACEELEMENT Trace metals in pyrite and marcasite from the Agua Rica porphyryhigh sulfidation epithermal deposit, Catamarca, Argentina: Textural features and metal zoning at the porphyry to epithermal transition Ore Geology Reviews, 2015 Marta Franchini Laura Maydagan David Lentz Martin Reich Marta Franchini Laura Maydagan(PDF) Trace metals in pyrite and marcasite from the
Trace metals in pyrite and marcasite from the Agua
Pyrite from the porphyry stage is fine grained and depleted in most trace elements analyzed, except for traces of Co (up to 276 ppm) and Ni (up to 131 ppm) Pyrite from the epithermal stage is texturally complex, compositionally heterogeneous, and the trace metal content varies with depth and within substages of mineralization Revised version, 10 August 2006 Arsenic incorporation into FeS2 pyrite and its influence on dissolution: a DFT study Marc Blancharda, Kate Wrightb, C Richard A Catlowa a Royal Institution of Great Britain, 21 Albemarle Street, London W1S 4BS, UK b Nanochemistry Research Institute, Department of Applied Chemistry, Curtin University of Technology, PO Box U1987, Perth 6845, Arsenic incorporation into FeS2 pyrite and its influence systems, but their incorporation into pyrite may be severely limited All other candidate alloys exhibit large gap bowing effects due to size and/or electronegativity mismatch 52 Relative stability of pyrite and marcasite as a function of particle size 83 Photovoltaic Properties and SizepH Phase Stability of
Iron Pyrite (FeS2
Pyrite nanocrystals: A challenge Early results: aggregates • multiple FeS phases • difficult to crystallize • tends to aggregate Ilfidh Pyrite (FeS 2) cubic, E g = 095 eV (indirect; 101 eV direct gap) diamagnetic semiconductor (Van Vleck paramagnet) Mit(F S ) th h bi E 04 V(i di t) Iron sulfide phases Marcasite (FeS 2 orthorhombic, g A simple onestep hydrothermal method was developed to synthesize pyrite (FeS2) sheet and bulklike pyrite mineral The Fe/S molar ratio determines the phase of FeS2, including pyrite and marcasite The reaction temperature and time are key factors to regulate the structure, morphology, and size of pyrite Scanning electron and transmission electron microscopy showed the formation of Hydrothermal Monodisperse Microspherulite Pyrite: The reaction of FeS2 (pyrite) with gaseous H2O, O2, and H2O/O2 was investigated using horizontal attenuated total reflection Fourier transform infrared spectroscopy (HATRFTIR) Spectra were interpreted with the aid of hybrid molecular orbital/density functional theory calculations of sulfateiron hydroxide clusters Reaction of pyrite in gaseous H2O led primarily to the formation of iron Mechanistic Aspects of Pyrite Oxidation in an
Nickeliferous pyrite tracks pervasive hydrothermal
Nickeliferous pyrite tracks pervasive hydrothermal alteration in Martian regolith breccia: A study in NWA 7533 JeanPierre LORAND1*, Roger H HEWINS2,3, Laurent REMUSAT2, Brigitte ZANDA2,3,4, Sylvain PONT2, Hugues LEROUX5, Maya MARINOVA6, Damien JACOB5, Munir HUMAYUN7, Alexander NEMCHIN8, Marion GRANGE8, Allen KENNEDY8, and Christa GOPEL€ 9 pyrite may represent mixing of pyrite with fi ne layers of arsenopyrite or marcasitetype phases, and that the gold is structurally bound in the latter as Au+ and Au0 Another important consideration is that models of traceelement incorporation in pyrite have been based on studies of samples from mineral deposits (sediCRYSTALLOGRAPHIC CONTROLS ON TRACEELEMENT Pyrite from the porphyry stage is fine grained and depleted in most trace elements analyzed, except for traces of Co (up to 276 ppm) and Ni (up to 131 ppm) Pyrite from the epithermal stage is texturally complex, compositionally heterogeneous, and the trace metal content varies with depth and within substages of mineralizationTrace metals in pyrite and marcasite from the Agua
Photovoltaic Properties and SizepH Phase Stability of
systems, but their incorporation into pyrite may be severely limited All other candidate alloys exhibit large gap bowing effects due to size and/or electronegativity mismatch 52 Relative stability of pyrite and marcasite as a function of particle size 83 Repositorio académico de la Universidad de Chile Tesis, artículos y libros publicados en formato digital con distintos niveles de accesoTrace metals in pyrite and marcasite from the Agua Transformation of pyrite to pyrrhotite in the presence of AuAg alloys at 500 °C American Mineralogist Synsedimentary, Diagenetic, and Metamorphic Pyrite, Pyrrhotite, and Marcasite at the Homestake BIFHosted Gold Deposit, South Dakota, USA: Insights on AuAs Ore Genesis from Textural and LAICPMS Trace Element StudiesStrength and deformation of pyrite and pyrrhotite
Iron Pyrite (FeS2
Pyrite nanocrystals: A challenge Early results: aggregates • multiple FeS phases • difficult to crystallize • tends to aggregate Ilfidh Pyrite (FeS 2) cubic, E g = 095 eV (indirect; 101 eV direct gap) diamagnetic semiconductor (Van Vleck paramagnet) Mit(F S ) th h bi E 04 V(i di t) Iron sulfide phases Marcasite (FeS 2 orthorhombic, g Reich M, Becker U (2006) Firstprinciples calculations of the thermodynamic mixing properties of arsenic incorporation into pyrite and marcasite Chem Geol 225(3):278–290 Article Google Scholar Reuss A, Angnew Z (1929) A calculation of the bulk Firstprinciples study of highpressure stability The disulfides of iron occur in two modes — mainly pyrite and occasionally marcasite with wide size ranges and in various forms, such as: framboid, colloidal precipitate, colloformbanded, fine disseminations, discrete grains, dendritic (feathery), recrystallized, nuggets, discoidal, massive, cavityfracture and cleatfillingsMineral matter and the nature of pyrite in some high
Hydrothermal Monodisperse Microspherulite Pyrite:
A simple onestep hydrothermal method was developed to synthesize pyrite (FeS2) sheet and bulklike pyrite mineral The Fe/S molar ratio determines the phase of FeS2, including pyrite and marcasite The reaction temperature and time are key factors to regulate the structure, morphology, and size of pyrite Scanning electron and transmission electron microscopy showed the formation of Solubility of gold in arsenian pyrite MARTIN REICH,1,2,*STEPHEN E KESLER,1 SATOSHI UTSUNOMIYA,1 CHRISTOPHER S PALENIK,1,3 STEPHEN L CHRYSSOULIS,4 AND RODNEY C EWING 1 1Department of Geological Sciences, University of Michigan, Ann Arbor, MI 481091063, USA 2Departamento de Geología, Facultad de Ciencias Físicas y Matemáticas, Universidad de Chile, Solubility of gold in arsenian pyrite