Journal articles: 'Arsenian pyrite'

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Gopon, Phillip, James O. Douglas, Maria A. Auger, Lars Hansen, Jon Wade, Jean S. Cline, Laurence J. Robb, and Michael P. Moody. "A Nanoscale Investigation of Carlin-Type Gold Deposits: An Atom-Scale Elemental and Isotopic Perspective." Economic Geology 114, no. 6 (September 1, 2019): 1123–33. http://dx.doi.org/10.5382/econgeo.4676.

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Abstract Carlin-type gold deposits are one of the most important gold mineralization styles in the world. Despite their economic importance and the large volume of work that has been published, there remain crucial questions regarding their metallogenesis. Much of this uncertainty is due to the cryptic nature of the gold occurrence, with gold occurring as dispersed nanoscale inclusions within host pyrite rims that formed on earlier formed barren pyrite cores. The small size of the gold inclusions has made determining their nature within the host sulfides and the mechanisms by which they precipitated from the ore fluids particularly problematic. This study combines high-resolution electron probe microanalysis (EPMA) with atom probe tomography (APT) to constrain whether the gold occurs as nanospheres or is dispersed within the Carlin pyrites. APT offers the unique capability of obtaining major, minor, trace, and isotopic chemical information at near-atomic spatial resolution. We use this capability to investigate the atomic-scale distribution of trace elements within Carlin-type pyrite rims, as well as the relative differences of sulfur isotopes within the rim and core of gold-hosting pyrite. We show that gold within a sample from the Turquoise Ridge deposit (Nevada) occurs within arsenian pyrite overgrowth (rims) that formed on a pyrite core. Furthermore, this As-rich rim does not contain nanonuggets of gold and instead contains dispersed lattice-bound Au within the pyrite crystal structure. The spatial correlation of gold and arsenic within our samples is consistent with increased local arsenic concentrations that enhanced the ability of arsenian pyrite to host dispersed gold (Kusebauch et al., 2019). We hypothesize that point defects in the lattice induced by the addition of arsenic to the pyrite structure facilitate the dissemination of gold. The lack of gold nanospheres in our study is consistent with previous work showing that dispersed gold in arsenian pyrite can occur in concentrations up to ~1:200 (gold/arsenic). We also report a method for determining the sulfur isotope ratios from atom probe data sets of pyrite (±As) that illustrates a relative change between the pyrite core and its Au and arsenian pyrite rim. This spatial variation confirms that the observed pyrite core-rim structure is due to two-stage growth involving a sedimentary or magmatic-hydrothermal core and hydrothermal rim, as opposed to precipitation from an evolving hydrothermal fluid.

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Filimonova, Olga, Alexander Trigub, Maximilian Nickolsky, Elena Kovalchuk, Vera Abramova, Mauro Rovezzi, Elena Belogub, Ilya Vikentyev, and Boris Tagirov. "X-ray absorption spectroscopy study of the chemistry of «invisible» Au in arsenian pyrites." E3S Web of Conferences 98 (2019): 05007. http://dx.doi.org/10.1051/e3sconf/20199805007.

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Arsenian pyrite is an abundant mineral occurring in many geological settings at the Earth’s surface, including hydrothermal ore deposits which are the main source of Au. So-called “invisible” (or refractory) form of Au is present in pyrites in all types of these deposits, and its concentration is often directly correlated with As content. Here we report results of the investigation of the local atomic structure of Au in natural (Cu-Au-porphyry) and synthetic (450°C/ 1 kbar, 300°C/ Psat) As-free and As-bearing pyrites by means of X-ray absorption spectroscopy (XAS). In addition, the state of As was determined in pyrite samples from Carlin-type deposit. XANES/EXAFS measurements, compiled with previously published data, revealed the chemical state (valence state, local atomic environment) of Au and As in arsenian pyrites. Au is present in the solid solution state (Au1+ in the Fe position, octahedrally coordinated by S atoms), as well as in Au1+2S clusters (Au1+ linearly coordinated by 2 S atoms). The admixture of As has no effect on the Au valence state and Au-S interatomic distance, except one synthetic sample containing a minor amount of FeAsS. Arsenic mostly incorporates into the anion site in pyrite lattice (S1-↔As1-). Our data demonstrate that pyrites of hydrothermal origin can host up to ~300 ppm of structurally bound “invisible” Au independently of As content.

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Fischer, Alicia, James Saunders, Sara Speetjens, Justin Marks, Jim Redwine, Stephanie R. Rogers, Ann S. Ojeda, Md Mahfujur Rahman, Zeki M. Billor, and Ming-Kuo Lee. "Long-Term Arsenic Sequestration in Biogenic Pyrite from Contaminated Groundwater: Insights from Field and Laboratory Studies." Minerals 11, no. 5 (May 19, 2021): 537. http://dx.doi.org/10.3390/min11050537.

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Pumping groundwater from arsenic (As)-contaminated aquifers exposes millions of people, especially those in developing countries, to high doses of the toxic contaminant. Previous studies have investigated cost-effective techniques to remove groundwater arsenic by stimulating sulfate-reducing bacteria (SRB) to form biogenic arsenian pyrite. This study intends to improve upon these past methods to demonstrate the effectiveness of SRB arsenic remediation at an industrial site in Florida. This study developed a ferrous sulfate and molasses mixture to sequester groundwater arsenic in arsenian pyrite over nine months. The optimal dosage of the remediating mixture consisted of 5 kg of ferrous sulfate, ~27 kg (60 lbs) of molasses, and ~1 kg (2 lbs) of fertilizer per 3785.4 L (1000 gallons) of water. The remediating mixture was injected into 11 wells hydrologically upgradient of the arsenic plume in an attempt to obtain full-scale remediation. Groundwater samples and precipitated biominerals were collected from June 2018 to March 2019. X-ray diffraction (XRD), X-ray fluorescence (XRF), electron microprobe (EMP), and scanning electron microscope (SEM) analyses determined that As has been sequestered mainly in the form of arsenian pyrite, which rapidly precipitated as euhedral crystals and spherical aggregates (framboids) 1–30 μm in diameter within two weeks of the injection. The analyses confirmed that the remediating mixture and injection scheme reduced As concentrations to near or below the site’s clean-up standard of 0.05 mg/L over the nine months. Moreover, the arsenian pyrite contained 0.03–0.89 weight percentage (wt%) of sequestered arsenic, with >80% of groundwater arsenic removed by SRB biomineralization. Considering these promising findings, the study is close to optimizing an affordable procedure for sequestrating dissolved As in industry settings.

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Stefanova, Elitsa, Milen Kadiyski, Stoyan Georgiev, Atanas Hikov, Sylvina Georgieva, and Irena Peytcheva. "Optical cathodoluminescence petrography, combined with SEM and LA-ICP-MS analyses: a case study from the Elatsite porphyry Cu-Au deposit." Review of the Bulgarian Geological Society 83, no. 3 (December 2022): 117–20. http://dx.doi.org/10.52215/rev.bgs.2022.83.3.117.

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In the present research, we have applied a combination of Cold-CL petrography with two in-situ techniques (SEM-EDS and LA-ICP-MS) to study quartz-pyrite-sericite veins with some carbonates from the Elatsite porphyry Cu-Au deposit. Based on Cold-CL images, we found out that these veins are formed during two stages: quartz-pyrite with sericite and later quartz-carbonate with chlorite. Together with the quartz and carbonates small amount of arsenian pyrite, hematite, chalcopyrite, sphalerite, galena and apatite are precipitated. SEM-EDS and LA-ICP-MS allowed determining that the observed zoning of the pyrite from Q-Py stage is due to a variable Co and Ni content. Similarly, the zonal growth of calcite is due to variable Mn content. Pyrite and arsenian pyrite have different trace element composition. Arsenian pyrite has elevated Au, Ag, Cu, Pb, Sb and Tl contents compared to the pyrite. The combination of the three techniques was essential for resolving temporal relationships between the minerals within quartz-pyrite-carbonate veins and changes of the composition of the pyrite from the quartz-pyrite-sericite to the later quartz-carbonate stage.

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Reich, Martin, Stephen E. Kesler, Satoshi Utsunomiya, Christopher S. Palenik, Stephen L. Chryssoulis, and Rodney C. Ewing. "Solubility of gold in arsenian pyrite." Geochimica et Cosmochimica Acta 69, no. 11 (June 2005): 2781–96. http://dx.doi.org/10.1016/j.gca.2005.01.011.

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Stepanov, Aleksandr S., Ross R. Large, Ekaterina S. Kiseeva, Leonid V. Danyushevsky, Karsten Goemann, Sebastien Meffre, Irina Zhukova, and Ivan A. Belousov. "Phase relations of arsenian pyrite and arsenopyrite." Ore Geology Reviews 136 (September 2021): 104285. http://dx.doi.org/10.1016/j.oregeorev.2021.104285.

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7

Voudouris, Panagiotis, Marianna Kati, Andreas Magganas, Manuel Keith, Eugenia Valsami-Jones, Karsten Haase, Reiner Klemd, and Mark Nestmeyer. "Arsenian Pyrite and Cinnabar from Active Submarine Nearshore Vents, Paleochori Bay, Milos Island, Greece." Minerals 11, no. 1 (December 25, 2020): 14. http://dx.doi.org/10.3390/min11010014.

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Active, shallow-water (2–10 m below sea level) and low temperature (up to 115 °C) hydrothermal venting at Paleochori Bay, nearshore Milos Island, Greece, discharges CO2 and H2S rich vapors (e.g., low-Cl fluid) and high-salinity liquids, which leads to a diverse assemblage of sulfide and alteration phases in an area of approximately 1 km2. Volcaniclastic detritus recovered from the seafloor is cemented by hydrothermal pyrite and marcasite, while semi-massive to massive pyrite-marcasite constitute mounds and chimney-like edifices. Paragenetic relationships indicate deposition of two distinct mineralogical assemblages related to the venting of high-Cl and low-Cl fluids, respectively: (1) colloform As- and Hg-bearing pyrite (Py I), associated with marcasite, calcite, and apatite, as well as (2) porous and/or massive As-rich pyrite (Py II), associated with barite, alunite/jarosite, and late-stage hydrous ferric oxides. Mercury, in the form of cinnabar, occurs within the As-rich pyrite (Py I) layers, usually forming distinct cinnabar-enriched micro-layers. Arsenic in colloform pyrite I shows a negative correlation with S indicating that As1− dominates in the pyrite structure suggesting formation from a relatively reducing As-rich fluid at conditions similar to low-sulfidation epithermal systems. On the contrary, As3+ dominates in the structure of porous to massive pyrite II suggesting deposition from a sulfate-dominated fluid with lower pH and higher fO2. Bulk sulfide data of pyrite-bearing hydrothermal precipitates also show elevated As (up to 2587 ppm) together with various epithermal-type elements, such as Sb (up to 274 ppm), Tl (up to 513 ppm), and Hg (up to 34 ppm) suggesting an epithermal nature for the hydrothermal activity at Paleochori Bay. Textural relationships indicate a contemporaneous deposition of As and Hg, which is suggested to be the result of venting from both high-salinity, liquid-dominated, as well as CO2- and H2S-rich vapor-dominated fluids that formed during fluid boiling. The CO2- and H2S-rich vapor that physically separated during fluid boiling from the high-salinity liquid led to calcite formation upon condensation in seawater together with the precipitation of As- and Hg-bearing pyrite I. This also led to the formation of sulfuric acid, thereby causing leaching and dissolution of primary iron-rich minerals in the volcaniclastic sediments, finally resulting in pyrite II precipitation in association with alunite/jarosite. The Paleochori vents contain the first documented occurrence of cinnabar on the seafloor in the Mediterranean area and provide an important link between offshore hydrothermal activity and the onshore mercury and arsenic mineralizing system on Milos Island. The results of this study therefore demonstrate that metal and metalloid precipitation in shallow-water continental arc environments is controlled by epithermal processes known from their subaerial analogues.

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Cabri, Louis J., Stephen L. Chryssoulis, John L. Campbell, and William J. Teesdale. "Comparison of in-situ gold analyses in arsenian pyrite." Applied Geochemistry 6, no. 2 (January 1991): 225–30. http://dx.doi.org/10.1016/0883-2927(91)90032-k.

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9

Qiu, Guohong, Tianyu Gao, Jun Hong, Yao Luo, Lihu Liu, Wenfeng Tan, and Fan Liu. "Mechanisms of interaction between arsenian pyrite and aqueous arsenite under anoxic and oxic conditions." Geochimica et Cosmochimica Acta 228 (May 2018): 205–19. http://dx.doi.org/10.1016/j.gca.2018.02.051.

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10

Deditius, A. P., S. Utsunomiya, R. C. Ewing, and S. E. Kesler. "Nanoscale "liquid" inclusions of As-Fe-S in arsenian pyrite." American Mineralogist 94, no. 2-3 (February 1, 2009): 391–94. http://dx.doi.org/10.2138/am.2009.3116.

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Hu, Kai, Moucheng Pan, Jian Cao, Yin Liu, and Shanchu Han. "The Au-Hosting Minerals and Process of Formation of the Carlin-Type Bojitian Deposit, Southwestern China." Geofluids 2017 (2017): 1–22. http://dx.doi.org/10.1155/2017/2417209.

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The recently discovered middle-sized Bojitian Carlin-type Au deposit is located in southwestern Guizhou Province, China, near the well-known Shuiyindong super-large-sized deposit. To improve the understanding on this deposit, here we investigate the minerals that host Au and the occurrence of Au in the deposit, using a combination of microscopic work and electron probe microanalysis (EPMA). Based on the results, the formation of the deposit was addressed. Results indicate that the dominant minerals that host Au include arsenian pyrite and arsenopyrite. Au in the cores of zoned pyrite exists mainly as natural nanoscale Au (Au0), while Au in the rims exists mainly as solid solution Au (Au+), but it likely also exists in the rims as natural nanoscale Au. The framboidal, coarse-grained, and banded pyrite types contain both natural nanoscale Au0 and solid solution Au+. The arsenopyrite is of hydrothermal origin, and Au within the arsenopyrite exists as gold solution Au+. The Bojitian deposit was formed from As-bearing, H2S-rich, low-to-medium-temperature fluids that migrated along faults and other channels. Au that was already present in the strata or source beds migrated with the fluids in the form of Au(HS)− and ore-forming fluids were then formed in the reducing environment. The ore-forming fluids interacted with Fe-rich carbonates to form an abundance of Au-hosting arsenian sulfides.

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Simon, Grigore, Hui Huang, James E. Penner-Hahn, Stephen E. Kesler, and Li-Shun Kao. "Oxidation state of gold and arsenic in gold-bearing arsenian pyrite." American Mineralogist 84, no. 7-8 (August 1, 1999): 1071–79. http://dx.doi.org/10.2138/am-1999-7-809.

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Saunders, Jim, Mark Steltenpohl, and Robert B. Cook. "Gold Exploration and Potential of the Appalachian Piedmont of Eastern Alabama." SEG Discovery, no. 94 (July 1, 2013): 1–17. http://dx.doi.org/10.5382/segnews.2013-94.fea.

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ABSTRACT: The discovery and production of gold from epithermal and volcanogenic massive sulfide deposits in the Carolina slate belt of the southern Appalachians perhaps have overshadowed the gold potential of orogenic gold deposits in relatively higher grade metamorphic terranes of the southern Appalachian Piedmont. There has been a limited amount of exploration in the non-Carolina slate belt southern Appalachians since the early 1980s. Here we describe some of the recent exploration activity and geology of gold occurrences in the most productive part of the Alabama Piedmont, including the Goldville and Devil’s Backbone districts. In this area, there is a strong geochemical association of gold and arsenic in bedrock, saprolite, and soils, which reflects the mineralogical association of gold with arsenian pyrite and arsenopyrite in mineralized zones.

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Xia, Fang, Jing Zhao, Joël Brugger, Yung Ngothai, Brian O'Neill, Guorong Chen, and Allan Pring. "Experimental synthesis of auriferous arsenian pyrite/marcasite by pseudomorphic replacement of pyrrhotite." Journal of Geochemical Exploration 101, no. 1 (April 2009): 114. http://dx.doi.org/10.1016/j.gexplo.2008.11.051.

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Laird, J. S., C. M. MacRae, A. Halfpenny, R. Large, and C. G. Ryan. "Microelectronic junctions in arsenian pyrite due to impurity and mixed sulfide heterogeneity." American Mineralogist 100, no. 1 (December 23, 2014): 26–34. http://dx.doi.org/10.2138/am-2015-4648.

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Deditius, Artur P., Satoshi Utsunomiya, Devon Renock, Rodney C. Ewing, Chintalapalle V. Ramana, Udo Becker, and Stephen E. Kesler. "A proposed new type of arsenian pyrite: Composition, nanostructure and geological significance." Geochimica et Cosmochimica Acta 72, no. 12 (June 2008): 2919–33. http://dx.doi.org/10.1016/j.gca.2008.03.014.

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Deditius, Artur P., and Martin Reich. "Constraints on the solid solubility of Hg, Tl, and Cd in arsenian pyrite." American Mineralogist 101, no. 6 (June 2016): 1451–59. http://dx.doi.org/10.2138/am-2016-5603.

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Jiuling, Li, Qi Feng, and Xu Qingsheng. "A negatively charged species of gold in minerals - Further study of chemically bound gold in arsenopyrite and arsenian pyrite." Neues Jahrbuch für Mineralogie - Monatshefte 2003, no. 5 (May 12, 2003): 193–214. http://dx.doi.org/10.1127/0028-3649/2003/2003-0193.

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Sun, Lei, Shuhab Khan, and Peter Shabestari. "Integrated Hyperspectral and Geochemical Study of Sediment-Hosted Disseminated Gold at the Goldstrike District, Utah." Remote Sensing 11, no. 17 (August 23, 2019): 1987. http://dx.doi.org/10.3390/rs11171987.

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The Goldstrike district in southwest Utah is similar to Carlin-type gold deposits in Nevada that are characterized by sediment-hosted disseminated gold. Suitable structural and stratigraphic conditions facilitated precipitation of gold in arsenian pyrite grains from ascending gold-bearing fluids. This study used ground-based hyperspectral imaging to study a core drilled in the Goldstrike district covering the basal Claron Formation and Callville Limestone. Spectral modeling of absorptions at 2340, 2200, and 500 nm allowed the extraction of calcite, clay minerals, and ferric iron abundances and identification of lithology. This study integrated remote sensing and geochemistry data and identified an optimum stratigraphic combination of limestone above and siliciclastic rocks below in the basal Claron Formation, as well as decarbonatization, argillization, and pyrite oxidation in the Callville Limestone, that are related with gold mineralization. This study shows an example of utilizing ground-based hyperspectral imaging in geological characterization, which can be broadly applied in the determination of mining interests and classification of ore grades. The utilization of this new terrestrial remote sensing technique has great potentials in resource exploration and exploitation.

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Kadel-Harder, Irene M., Paul G. Spry, Audrey L. McCombs, and Haozhe Zhang. "Identifying pathfinder elements for gold in bulk-rock geochemical data from the Cripple Creek Au–Te deposit: a statistical approach." Geochemistry: Exploration, Environment, Analysis 21, no. 1 (October 26, 2020): geochem2020–048. http://dx.doi.org/10.1144/geochem2020-048.

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The Cripple Creek alkaline igneous rock-related, low-sulfidation epithermal gold telluride deposit, Colorado, is hosted in the 10 km wide Oligocene alkaline volcanic Cripple Creek diatreme in Proterozoic rocks. Gold occurs as native gold, Au-tellurides, and in the structure of arsenian pyrite, in potassically altered high-grade veins, and as disseminations in the host rocks.Correlation coefficients, principal component analysis, hierarchical cluster analysis and random forests were used to analyse major and trace element compositions of 995 rock samples primarily from low-grade gold mineralization in drill core from three currently operating pits (Wild Horse Extension, Globe Hill and Schist Island) in the northwestern part of the Cripple Creek diatreme. These methods suggest that Ag, As, Bi, Te and W are the best pathfinders to gold mineralization in low-grade disseminated ore. Although Mo correlates with gold in other studies and is spatially related to gold veins, molybdenite post-dated the formation of gold and is likely related to a late-stage porphyry overprint. These elements, in conjunction with mineralogical studies, indicate that tellurides, fluorite, quartz, carbonates, roscoelite, tennantite-tetrahedrite, pyrite, sphalerite, muscovite, monazite, bastnäsite and hübnerite serve as exploration guides to ore.

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Fleet, Michael E., and A. Hamid Mumin. "Gold-bearing arsenian pyrite and marcasite and arsenopyrite from Carlin Trend gold deposits and laboratory synthesis." American Mineralogist 82, no. 1-2 (February 1, 1997): 182–93. http://dx.doi.org/10.2138/am-1997-1-220.

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Vishiti, Akumbom, Sven Petersen, Colin Devey, and Cheo Emmanuel Suh. "Arsenian pyrite-bearing altered volcanics dredged SE of Cheshire Seamount, western Woodlark Basin, Papua New Guinea." Neues Jahrbuch f??r Mineralogie - Abhandlungen: Journal of Mineralogy and Geoche 190, no. 3 (April 1, 2013): 327–40. http://dx.doi.org/10.1127/0077-7757/2013/0241.

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Morishita, Yuichi, Nobutaka Shimada, and Kazuhiko Shimada. "Invisible gold in arsenian pyrite from the high-grade Hishikari gold deposit, Japan: Significance of variation and distribution of Au/As ratios in pyrite." Ore Geology Reviews 95 (April 2018): 79–93. http://dx.doi.org/10.1016/j.oregeorev.2018.02.029.

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Gadzhalov, Aleksandar, Irina Marinova, Mihail Tarassov, and Elena Tacheva. "Coupled and uncoupled to δ34S behavior of gold and silver in pyrite and marcasite from the low-sulfidation Sarnak gold deposit, SE Bulgaria." Review of the Bulgarian Geological Society 83, no. 3 (December 2022): 185–88. http://dx.doi.org/10.52215/rev.bgs.2022.83.3.185.

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In this study, the contents of Au and Ag in five pyrite±marcasite samples from the Sarnak gold deposit, the respective δ34S, and the sample distances to the contact between metamorphic basement and overlying sedimentary cover were considered. We found that two samples from lower horizons (levels of 69 and 30 m below the contact) display relatively low Au and Ag contents, negative values of δ34SV-CDT (–3.14 and –6.42‰) and pronounced oscillatory zoning, resulting from oscillating contents of As. Three samples from higher horizons (levels of 8, 7 and 0 m below the contact) have higher Au and Ag contents, positive or slightly negative values of δ34SV-CDT (+0.5, +1.73 and –1.85‰) and poorly expressed or absent arsenian zoning. Two of them contain microscopic electrum and adularia. Based on these contrasting features we assume different mechanisms of precipitation: intense fluid-rock interaction for samples from lower horizons under steady conditions and boiling of fluid for samples from higher horizons under fluctuating conditions.

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Simon, Grigore, Stephen E. Kesler, and Stephen Chryssoulis. "Geochemistry and textures of gold-bearing arsenian pyrite, Twin Creeks, Nevada; implications for deposition of gold in carlin-type deposits." Economic Geology 94, no. 3 (May 1, 1999): 405–21. http://dx.doi.org/10.2113/gsecongeo.94.3.405.

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Sung, Y. H., J. Brugger, C. L. Ciobanu, A. Pring, W. Skinner, and M. Nugus. "Invisible gold in arsenian pyrite and arsenopyrite from a multistage Archaean gold deposit: Sunrise Dam, Eastern Goldfields Province, Western Australia." Mineralium Deposita 44, no. 7 (June 10, 2009): 765–91. http://dx.doi.org/10.1007/s00126-009-0244-4.

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Sung, Y. H., J. Brugger, C. L. Ciobanu, A. Pring, W. Skinner, L. V. Danyushevsky, and M. Nugus. "Invisible gold in arsenian pyrite and arsenopyrite from a multistage Archaean gold deposit: Sunrise Dam, Eastern Goldfields Province, Western Australia." Mineralium Deposita 44, no. 7 (July 16, 2009): 793. http://dx.doi.org/10.1007/s00126-009-0251-5.

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Spangenberg, Jorge E., Nicolas J. Saintilan, and Sabina Strmić Palinkaš. "Safe, accurate, and precise sulfur isotope analyses of arsenides, sulfarsenides, and arsenic and mercury sulfides by conversion to barium sulfate before EA/IRMS." Analytical and Bioanalytical Chemistry 414, no. 6 (January 23, 2022): 2163–79. http://dx.doi.org/10.1007/s00216-021-03854-y.

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AbstractThe stable isotope ratios of sulfur (δ34S relative to Vienna Cañon Diablo Troilite) in sulfates and sulfides determined by elemental analysis and isotope ratio mass spectrometry (EA/IRMS) have been proven to be a remarkable tool for studies of the (bio)geochemical sulfur cycles in modern and ancient environments. However, the use of EA/IRMS to measure δ34S in arsenides and sulfarsenides may not be straightforward. This difficulty can lead to potential health and environmental hazards in the workplace and analytical problems such as instrument contamination, memory effects, and a non-matrix-matched standardization of δ34S measurements with suitable reference materials. To overcome these practical and analytical challenges, we developed a procedure for sulfur isotope analysis of arsenides, which can also be safely used for EA/IRMS analysis of arsenic sulfides (i.e., realgar, orpiment, arsenopyrite, and arsenian pyrite), and mercury sulfides (cinnabar). The sulfur dioxide produced from off-line EA combustion was trapped in an aqueous barium chloride solution in a leak-free system and precipitated as barium sulfate after quantitative oxidation of hydrogen sulfite by hydrogen peroxide. The derived barium sulfate was analyzed by conventional EA/IRMS, which bracketed the δ34S values of the samples with three international sulfate reference materials. The protocol (BaSO4-EA/IRMS) was validated by analyses of reference materials and laboratory standards of sulfate and sulfides and achieved accuracy and precision comparable with those of direct EA/IRMS. The δ34S values determined by BaSO4-EA/IRMS in sulfides (arsenopyrite, arsenic, and mercury sulfides) samples from different origins were comparable to those obtained by EA/IRMS, and no sulfur isotope fractionations were introduced during sample preparation. We report the first sulfur isotope data of arsenides obtained by BaSO4-EA/IRMS. Graphical abstract

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Merkulova, Margarita, Olivier Mathon, Pieter Glatzel, Mauro Rovezzi, Valentina Batanova, Philippe Marion, Marie-Christine Boiron, and Alain Manceau. "Revealing the Chemical Form of “Invisible” Gold in Natural Arsenian Pyrite and Arsenopyrite with High Energy-Resolution X-ray Absorption Spectroscopy." ACS Earth and Space Chemistry 3, no. 9 (July 19, 2019): 1905–14. http://dx.doi.org/10.1021/acsearthspacechem.9b00099.

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Su, Wenchao, Hongtao Zhang, Ruizhong Hu, Xi Ge, Bin Xia, Yanyan Chen, and Chen Zhu. "Mineralogy and geochemistry of gold-bearing arsenian pyrite from the Shuiyindong Carlin-type gold deposit, Guizhou, China: implications for gold depositional processes." Mineralium Deposita 47, no. 6 (January 29, 2011): 653–62. http://dx.doi.org/10.1007/s00126-011-0328-9.

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Su, Wenchao, Bin Xia, Hongtao Zhang, Xingchun Zhang, and Ruizhong Hu. "Visible gold in arsenian pyrite at the Shuiyindong Carlin-type gold deposit, Guizhou, China: Implications for the environment and processes of ore formation." Ore Geology Reviews 33, no. 3-4 (June 2008): 667–79. http://dx.doi.org/10.1016/j.oregeorev.2007.10.002.

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Pašava, Jan, Lukáš Ackerman, Patricie Halodová, Ondřej Pour, Jana Ďurišová, Federica Zaccarini, Thomas Aiglsperger, and Anna Vymazalová. "Concentrations of platinum-group elements (PGE), Re and Au in arsenian pyrite and millerite from Mo–Ni–PGE-Au black shales (Zunyi region, Guizhou Province, China): results from LA-ICPMS study." European Journal of Mineralogy 29, no. 4 (October 10, 2017): 623–33. http://dx.doi.org/10.1127/ejm/2017/0029-2640.

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Wang, Shuhao, Junfeng Shen, Baisong Du, Kexin Xu, Zhengshuai Zhang, and Chengyu Liu. "The Relationship between Natural Pyrite and Impurity Element Semiconductor Properties: A Case Study of Vein Pyrite from the Zaozigou Gold Deposit in China." Minerals 11, no. 6 (June 1, 2021): 596. http://dx.doi.org/10.3390/min11060596.

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Pyrite is a common sulfide mineral in gold deposits, and its unique thermoelectricity has received extensive attention in the field of gold exploration. However, there is still a lack of detailed research and direct evidence about how impurity elements affect mineral semiconductor properties. In this paper, combined with first-principles calculations, laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) mapping technology and in situ Seebeck coefficient scanning probe technology were used to study the law of changing semiconductor properties in pyrite containing impurity elements such as As, Co, Ni, and Cu. The results showed that pyrite containing arsenic is a P-type semiconductor, and pyrites containing Ni, Co, Cu, and other elements are N-type semiconductors. When P-type pyrites containing As were supplemented with Ni, Cu, and other elements, the semiconductor type changed to N-type. However, Co addition did not change the semiconductor type of arsenic-rich pyrite. Pyrite formed under different temperature conditions tended to be enriched with different combinations of impurity elements, leading to the relative accumulation of P-type or N-type pyrites.

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Zachariáš, J., J. Frýda, B. Paterová, and M. Mihaljevič. "Arsenopyrite and As-bearing pyrite from the Roudný deposit, Bohemian Massif." Mineralogical Magazine 68, no. 1 (February 2004): 31–46. http://dx.doi.org/10.1180/0026461046810169.

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AbstractThe major- and trace-element chemistry of pyrite and arsenopyrite from the mesothermal Roudný gold deposits was studied by electron microprobe and laser ablation ICP-MS techniques. In total, four generations of pyrite and two of arsenopyrite were distinguished. The pyrite is enriched in As through an Fe (AsxS1–x)2 substitution mechanism. The As-rich zones of pyrite-2 (up to 4.5 wt.% As) are also enriched in gold (up to 20 ppm), lead (commonly up to 220 ppm, exceptionally up to 1500 ppm) and antimony (commonly <600 ppm, rarely up to 1350 ppm). Positive correlation of As and Au in the studied pyrites is not coupled with an Fe deficiency, in contrast to Au-rich As-bearing pyrites in Carlintype gold deposits. The As-rich pyrite-2 coprecipitated with the Sb-rich (1 –4.2 wt.%) and Au-rich (40 –150 ppm) arsenopyrite-1. The younger arsenopyrite-2 is significantly less enriched in these elements (0 –70 ppm of Au).The chemical zonality of pyrites in the Roudný gold deposits reflects the chemical evolution of orebearing fluids that are not observed in any other mineral phases. The data available suggest relatively high activity of sulphur and low activities of arsenic and gold during crystallization of the older pyrite generation (pyrite-1). Later, after particular dissolution of pyrite-1, Au-rich As-bearing pyrite-2 and arsenopyrite precipitated. These facts suggest a marked increase in the arsenic and gold activities in ore-bearing fluids. The As-content of pyrite-2 decreases in an oscillatory manner from the core to the rim, reflecting changes in the As activity or/and in the P-T conditions. The As-bearing pyrites were formed at temperatures of at least 320–330°C, based on arsenopyrite thermometers and fluid inclusion data.

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Chen, Guobao, Zhangfu Zhu, and Yong Qin. "Synthesis of Pure Micro- and Nanopyrite and Their Application for As (III) Removal from Aqueous Solution." Advances in Materials Science and Engineering 2016 (2016): 1–6. http://dx.doi.org/10.1155/2016/6290420.

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Arsenic is one of the materials that has a worldwide concern because of its high toxicity and chronic effects on human health. The existence of arsenic as As (III) is about 56 times poisonous as As (V) and more difficult to process. The investigation takes the pyrite as an adsorbent to remove As (III) from waste water. Different morphology and granularity of pyrite were synthesized by hydrothermal and liquid-phase precipitation methods, respectively. The findings show that the addition of pyrite nanoparticles to the solution provided highest As (III) removal efficiency of 88.53%. 1 gL−1pyrite nanoparticles can reduce the concentration of arsenite in the waste water from an initial As content of 30 mgL−1to 3.4 mgL−1at pH 11. Under the similar operating conditions, the synthetic micropyrite and natural pyrite have a lower As (III) removal; both were less than 70%. In addition, the synthetic pyrite nanowires obtained 86.70% removal efficiency of arsenite. The results confirmed that the morphology and granularity of pyrite can significantly influence the adsorption of arsenite removal from aqueous solution.

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Liang, Jin-long, Wei-dong Sun, Yi-liang Li, San-yuan Zhu, He Li, Yu-long Liu, and Wei Zhai. "An XPS study on the valence states of arsenic in arsenian pyrite: Implications for Au deposition mechanism of the Yang-shan Carlin-type gold deposit, western Qinling belt." Journal of Asian Earth Sciences 62 (January 2013): 363–72. http://dx.doi.org/10.1016/j.jseaes.2012.10.020.

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Topa, D., E. Makovicky, H. Tajedin, H. Putz, and G. Zagler. "Barikaite, Pb10Ag3(Sb8As11)Σ19S40, a new member of the sartorite homologous series." Mineralogical Magazine 77, no. 7 (October 2013): 3039–46. http://dx.doi.org/10.1180/minmag.2013.077.7.13.

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AbstractBarikaite, ideally Pb10Ag3(Sb8As11)Σ19S40, is a new mineral species from the Barika Au-Ag deposit, Azarbaijan Province, western Iran. It was formed in fractures developed in silica bands situated in massive banded pyrite and baryte ores. These fractures house veinlets that contain a number of Ag-As-Sb-Pb-rich sulfosalts, tetrahedrite-tennantite, realgar, pyrite and electrum. Barikaite appears as inclusions in guettardite. The mineral is opaque, greyish black with a metallic lustre; it is brittle without any discernible cleavage. In reflected light barikaite is greyish white, pleochroism is distinct, white to dark grey. Internal reflections are absent. In crossed polars, anisotropism is distinct with rotation tints in shades of grey. The reflectance data (%, in air) are: 37.0, 39.3 at 470 nm, 34.1, 36.9 at 546 nm, 33.1, 36.2 at 589 nm and 31.3, 34.1 at 650 nm. The Mohs hardness is 3–3½, microhardness VHN50 exhibits the range 192 – 212, with a mean value of 200 kg mm–2. The average results of five electron-microprobe analyses in a grain are (in wt.%): Pb 35.77(33), Ag 5.8(1), Tl 0.15(08), Sb 18.33(09), As 15.64(16), S 24.00(15), total 99.69(10) wt.%, corresponding to Pb9.31Ag2.90Tl0.04(Sb8.12As11.26)Σ19.36S40.37 (on the basis of 32Me + 40S = 72 a.p.f.u.). The simplified formula, Pb10Ag3(Sb8As11)Σ19S40, is in accordance with the results of a crystal-structure analysis, and requires Pb 37.89, Ag 5.91, Sb 17.79, As 15.05 and S 23.42 (wt.%). The variation of chemical composition is minor, the empirical formula ranging from Pb10.39Ag2.32Tl0.02Sb7.52As11.27S40.49 to Pb9.24Ag2.93Tl0.04Sb8.13As11.35S40.31. Barikaite has monoclinic symmetry, space group P21/n and unit-cell parameters a 8.5325(7) Å, b 8.0749(7) Å, c 24.828(2) Å, and b 99.077(6)o, Z = 1. Calculated density for the empirical formula is 5.34 (g cm–3). The strongest eight lines in the (calculated) powder-diffraction pattern [d in Å(I)(hkl)] are: 3.835(63)(022), 3.646(100)(016), 3.441(60)(212), 3.408(62)(14), 2.972(66)(16), 2.769(91)(222), 2.752(78)(24) and 2.133(54)(402). Barikaite is the N = 4 member of the sartorite homologous series with a near-equal role of As and Sb, which have an ordered distribution pattern in the structure. It is a close homeotype of rathite and more distantly related to dufrénoysite (both distinct, pure arsenian N = 4 members) and it completes the spectrum of Sb-rich members of the sartorite homologous series. The new mineral and its name have been approved by the IMA-CNMNC (IMA 2012-055).

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Tan, Xia, Xie, Wang, Wei, Zhao, Yan, and Li. "Two Hydrothermal Events at the Shuiyindong Carlin-Type Gold Deposit in Southwestern China: Insight from Sm–Nd Dating of Fluorite and Calcite." Minerals 9, no. 4 (April 12, 2019): 230. http://dx.doi.org/10.3390/min9040230.

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The Shuiyindong Gold Mine hosts one of the largest and highest-grade, strata-bound Carlin-type gold deposits discovered to date in Southwestern China. The outcrop stratigraphy and drill core data of the deposit reveal Middle–Upper Permian and Lower Triassic formations. The ore is mainly hosted in Upper Permian bioclastic limestone near the axis of an anticline. The gold is mainly hosted in arsenian pyrite and arsenopyrite, mainly existing in the form of crystal lattice gold, submicroscopic particles and nanoparticles. Fluorite commonly occurs at the vicinity of an unconformity between the Middle–Upper Permian formations, which is proposed to be the structural conduit that fed the ore ﬂuids. Calcite commonly fills fractures at the periphery of decarbonated rocks, which contain high grade orebodies. This study aimed to verify the occurrence of two distinct hydrothermal events at the Shuiyindong, based on Sm–Nd isotope dating of the fluorite and calcite. For this purpose, rare-earth element (REE) concentrations, Sm/Nd isotope ratios, and Sm–Nd isochron ages of the fluorite and calcite were determined. The fluorite and calcite contain relatively high total concentrations of REE (12.3–25.6 μg/g and 5.71–31.7 μg/g, respectively), exhibit variable Sm/Nd ratios (0.52–1.03 and 0.57–1.71, respectively), and yield Sm–Nd isochron ages of 200.1 ± 8.6 Ma and 150.2 ± 2.2 Ma, with slightly different initial εNd(t) values of −4.4 and −1.1, respectively. These two groups of Sm–Nd isochron ages suggest two episodes of hydrothermal events at the Shuiyindong gold deposit. The age of the calcite probably represents the late stage of the gold mineralization period. The initial εNd(t) values of the fluorite and calcite indicate that the Nd was probably derived from mixtures of basaltic volcanic tuff and bioclastic limestone from the Permian formations.

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Voisey, Christopher R., Andrew G. Tomkins, and Yanlu Xing. "Analysis of a Telescoped Orogenic Gold System: Insights from the Fosterville Deposit." Economic Geology 115, no. 8 (October 26, 2020): 1645–64. http://dx.doi.org/10.5382/econgeo.4767.

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Abstract The Fosterville gold (Au) deposit is hosted in the Bendigo zone within the western Lachlan orogen, southeast Australia, and contains three distinct mineralization styles: (1) refractory Au in fine-grained arsenopyrite and arsenian pyrite disseminated throughout metasedimentary rocks near brittle faults, (2) visible Au hosted in fault-controlled quartz-carbonate veins associated with stibnite mineralization, and (3) vein-hosted visible Au with little or no associated stibnite. Refractory Au mineralization is found throughout the deposit, whereas visible Au ± stibnite occurs deeper in the system (>800-m depth from surface). Thus, Fosterville provides a unique opportunity to study a telescoped orogenic Au system that changes mineralization style as a function of depth. Microscopy, neutron tomography, nanoscale secondary ion mass spectrometry, and field observations have been conducted to investigate mineralogical and structural controls on the various styles of Au mineralization. These observations are used as the foundation for reactive mass transport geochemical modeling using HCh software. Results are considered in the context of an evolving mineral system over the formation history of the deposit, and relative timing of mineralization is inferred. Two alternatives for the genesis of such a system include the following: (1) metal deposition was controlled by ongoing physicochemical changes at a very shallow level in the crust in one evolving mineralization stage or (2) two or three deposits formed in the same location, with each different style of mineralization representing a separate period of fluid infiltration, each potentially tens of millions of years apart. Based on careful observations, microanalysis, and thermodynamic modeling, we suggest that the latter is more likely. Therefore, we suggest that Fosterville is to be recognized as a telescoped orogenic Au system, where relatively high temperature mineralization and alteration assemblages were overprinted vertically by later, lower-temperature assemblages.

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Dave, Shailesh R., and K. H. Gupta. "Interactions of Acidithiobacillus ferrooxidans with Heavy Metals, Various Forms of Arsenic and Pyrite." Advanced Materials Research 20-21 (July 2007): 423–26. http://dx.doi.org/10.4028/www.scientific.net/amr.20-21.423.

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An arsenic resistant ferrous iron oxidizing bacterium Acidithiobacillus ferrooxidans (GenBank no. EF010878) was isolated from reactor leachate. The reactor leachate showed extreme environmental parameters. Ferrous iron concentrations of more than 60 g/L were found to be inhibitory in the presence and absence of arsenite. Ks values of 12.5 and 8.0 g/L ferrous sulphate and Vmax of 0.124 and 0.117 g/L/h/0.8 mg of protein were found in the presence and absence of arsenite respectively. At 14.9 g/L of arsenite and arsenate the culture showed 26.8 and 59.7 % ferrous iron oxidizing activity respectively. Amongst the metals studied, copper was found to be more toxic as compared to nickel and zinc. In the presence of 3.51 g/L nickel or 4.68 g/L zinc, about 30 % biooxidation activity was registered. In the pyrite oxidation study 87, 67 and 64 % of pyrite oxidation was found and 2.02, 3.19 and 5.96 g/L total iron was solubilized with 5, 10 and 20 g/L of pyrite respectively. The isolate was also able to oxidize refractory arsenopyrite gold ore and 0.531 g/L of arsenic was solubilized along with 0.872 g/L of soluble total iron. During this period the numbers of planktonic bacteria increased from 2.4 x 106 to 1.0 x 108 cells/mL.

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Jin, Xiao-Ye, Albert H. Hofstra, Andrew G. Hunt, Jian-Zhong Liu, Wu Yang, and Jian-Wei Li. "NOBLE GASES FINGERPRINT THE SOURCE AND EVOLUTION OF ORE-FORMING FLUIDS OF CARLIN-TYPE GOLD DEPOSITS IN THE GOLDEN TRIANGLE, SOUTH CHINA." Economic Geology 115, no. 2 (March 1, 2020): 455–69. http://dx.doi.org/10.5382/econgeo.4703.

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Abstract Precise constraints on the source and evolution of ore-forming fluids of Carlin-type gold deposits in the Golden Triangle (south China) are of critical importance for a better understanding of the ore genesis and a refined genetic model for gold mineralization. However, constraints on the source of ore fluid components have long been a challenge due to the very fine grained nature of the ore and gangue minerals in the deposits. Here we present He, Ne, and Ar isotope data of fluid inclusion extracts from a variety of ore and gangue minerals (arsenian pyrite, realgar, quartz, calcite, and fluorite) representing the main and late ore stages of three well-characterized major gold deposits (Shuiyindong, Nibao, and Yata) to provide significant new insights into the source and evolution of ore-forming fluids of this important gold province. Measured He isotopes have R/RA ratios ranging from 0.01 to 0.4 that suggest a maximum of 5% mantle helium with an R/RA of 8. The Ne and Ar isotope compositions are broadly comparable to air-saturated water, with a few analyses indicating the presence of an external fluid containing nucleogenic 38Ar and radiogenic 40Ar. Plotted on the 20Ne/4He vs. helium R/RA and 3He/20Ne vs. 4He/20Ne diagrams, the results define two distinct arrays that emanate from a common sedimentary pore fluid or deeply sourced metamorphic fluid end-member containing crustal He. The main ore-stage fluids are interpreted as a mixture of magmatic fluid containing mantle He and sedimentary pore fluid or deeply sourced metamorphic fluid with predominantly crustal He, whereas the late ore-stage fluids are a mixture of sedimentary pore fluid or deeply sourced metamorphic fluid bearing crustal He and shallow meteoric groundwater containing atmospheric He. Results presented here, when combined with independent evidence, support a magmatic origin for the ore-forming fluids. The ascending magmatic fluid mixed with sedimentary pore fluid or deeply sourced metamorphic fluid in the ore stage and subsequently mixed with the meteoric groundwater in the late ore stage, eventually producing the Carlin-type gold deposits in the Golden Triangle.

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Duquesne, K., S. Lebrun, C. Casiot, O. Bruneel, J. C. Personné, M. Leblanc, F. Elbaz-Poulichet, G. Morin, and V. Bonnefoy. "Immobilization of Arsenite and Ferric Iron by Acidithiobacillus ferrooxidans and Its Relevance to Acid Mine Drainage." Applied and Environmental Microbiology 69, no. 10 (October 2003): 6165–73. http://dx.doi.org/10.1128/aem.69.10.6165-6173.2003.

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ABSTRACT Weathering of the As-rich pyrite-rich tailings of the abandoned mining site of Carnoulès (southeastern France) results in the formation of acid waters heavily loaded with arsenic. Dissolved arsenic present in the seepage waters precipitates within a few meters from the bottom of the tailing dam in the presence of microorganisms. An Acidithiobacillus ferrooxidans strain, referred to as CC1, was isolated from the effluents. This strain was able to remove arsenic from a defined synthetic medium only when grown on ferrous iron. This A. ferrooxidans strain did not oxidize arsenite to arsenate directly or indirectly. Strain CC1 precipitated arsenic unexpectedly as arsenite but not arsenate, with ferric iron produced by its energy metabolism. Furthermore, arsenite was almost not found adsorbed on jarosite but associated with a poorly ordered schwertmannite. Arsenate is known to efficiently precipitate with ferric iron and sulfate in the form of more or less ordered schwertmannite, depending on the sulfur-to-arsenic ratio. Our data demonstrate that the coprecipitation of arsenite with schwertmannite also appears as a potential mechanism of arsenite removal in heavily contaminated acid waters. The removal of arsenite by coprecipitation with ferric iron appears to be a common property of the A. ferrooxidans species, as such a feature was observed with one private and three collection strains, one of which was the type strain.

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Ross-Lindeman, Jocelyn, and Dirk Kirste. "Characterization study of As and Se in pyrites from two historic mines in British Columbia." E3S Web of Conferences 98 (2019): 09026. http://dx.doi.org/10.1051/e3sconf/20199809026.

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Arsenic (As) and selenium (Se) can be toxic if they occur as soluble species at elevated concentrations. One process that can mobilize these elements into the environment is the oxidation of As- and Se-containing pyrites. This study presents the initial mineralogical (XRD, SEM-EDS, LA-ICP-MS, and synchrotron micro-XRF and micro-XANES) characterization of As- and Se-pyrites from two historic mines in British Columbia, the Sullivan Mine and the Sunro Mine. Results show that As occurs in some of the pyrites from the Sullivan Mine; comparison of the micro-XANES measurements to published data suggests As substitutes for sulphur. Selenium is detected in pyrites from the Sunro Mine but this Se is slightly more oxidized than measured in previous studies on Se-pyrite and further investigation of these samples is required. Results from this characterization study will be incorporated into the next phase of research measuring element mobilization after oxidation reactions to identify the effects of As or Se substitution on these reactions.

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Vega, Silvia, Jan Weijma, and Cees N. J. Buisman. "Immobilization of Arsenic by a Thermoacidophilic Mixed Culture with Pyrite as Energy Source." Solid State Phenomena 262 (August 2017): 656–59. http://dx.doi.org/10.4028/www.scientific.net/ssp.262.656.

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Arsenic is an abundant element associated with a wide range of minerals and a major contaminant in metallurgical wastewater. For the immobilization of arsenic, iron arsenate in the very stable mineral scorodite (FeAsO4 2H2O) is the preferred route. Microorganisms of the natural iron cycle living at pH below 2 and high temperatures can conduct the oxidation of ferrous iron with oxygen, which is not feasible chemically at these extreme conditions. Remarkably, at similar acidic conditions and high temperature these microorganisms can also carry out the oxidation of arsenite (As(III)) to arsenate (As(V)). Using these intrinsic features of the microorganisms, we have investigated the role of a thermoacidophilic mixed culture in the oxidation of As(III) and precipitation of (As(V) in the form of scorodite from a synthetic wastewater containing 6.7mM of As(III) and 0.5%Wt pyrite as main iron Fe(II) source. The results indicate that As(III) was completely oxidized from the synthetic wastewater in the presence of pyrite and scorodite was formed only in presence of the mixed culture at a Fe/As:1.3. This is a combination of biological oxidation and biocrystallisation accomplished to the presence of pyrite not only as the main energy source for the microorganisms, but as catalyst in the As(III) oxidation reaction.

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Dmitrijeva, Marija, Nigel J. Cook, Kathy Ehrig, Cristiana L. Ciobanu, Andrew V. Metcalfe, Maya Kamenetsky, Vadim S. Kamenetsky, and Sarah Gilbert. "Multivariate Statistical Analysis of Trace Elements in Pyrite: Prediction, Bias and Artefacts in Defining Mineral Signatures." Minerals 10, no. 1 (January 10, 2020): 61. http://dx.doi.org/10.3390/min10010061.

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Pyrite is the most common sulphide in a wide range of ore deposits and well known to host numerous trace elements, with implications for recovery of valuable metals and for generation of clean concentrates. Trace element signatures of pyrite are also widely used to understand ore-forming processes. Pyrite is an important component of the Olympic Dam Cu–U–Au–Ag orebody, South Australia. Using a multivariate statistical approach applied to a large trace element dataset derived from analysis of random pyrite grains, trace element signatures in Olympic Dam pyrite are assessed. Pyrite is characterised by: (i) a Ag–Bi–Pb signature predicting inclusions of tellurides (as PC1); and (ii) highly variable Co–Ni ratios likely representing an oscillatory zonation pattern in pyrite (as PC2). Pyrite is a major host for As, Co and probably also Ni. These three elements do not correlate well at the grain-scale, indicating high variability in zonation patterns. Arsenic is not, however, a good predictor for invisible Au at Olympic Dam. Most pyrites contain only negligible Au, suggesting that invisible gold in pyrite is not commonplace within the deposit. A minority of pyrite grains analysed do, however, contain Au which correlates with Ag, Bi and Te. The results are interpreted to reflect not only primary patterns but also the effects of multi-stage overprinting, including cycles of partial replacement and recrystallisation. The latter may have caused element release from the pyrite lattice and entrapment as mineral inclusions, as widely observed for other ore and gangue minerals within the deposit. Results also show the critical impact on predictive interpretations made from statistical analysis of large datasets containing a large percentage of left-censored values (i.e., those falling below the minimum limits of detection). The treatment of such values in large datasets is critical as the number of these values impacts on the cluster results. Trimming of datasets to eliminate artefacts introduced by left-censored data should be performed with caution lest bias be unintentionally introduced. The practice may, however, reveal meaningful correlations that might be diluted using the complete dataset.

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Zhang, Meng, Shu Juan Dai, Lian Tao Yu, Jia Hong Han, and Guo Zhen Liu. "Experimental Research on a Cyanidation of Gold Ore Containing Arsenic." Advanced Materials Research 826 (November 2013): 53–56. http://dx.doi.org/10.4028/www.scientific.net/amr.826.53.

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The main metal minerals are magnetic pyrite arsenopyrite pyrites, galenite sphalerite,etc.The main gangue minerals are quarts,sericite,chlorite,carbonate,etc.Nature gold,electrum,bullion and nature silver are main gold silver minerals. The useful element is gold and silver and the impurity is arsenic. The experimental results of cyanide leaching crude and flotation concentrate show that the index of leaching rate of gold and silver being 93.90% and 81.38% are got on the condition of grinding fineness being 95.3%-0.074mm，pulp thickness being 33%，dosage if CaO being 2.5kg/t（pH≈11），dosage of NaCN being 3.0kg/t,leaching time being 24h by leaching crude of gold and silver grade being 0.82g/t、4.78g/t.

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Vaughan, J. P., and A. Kyin. "Refractory gold ores in Archaean greenstones,Western Australia: mineralogy, gold paragenesis, metallurgical characterization and classification." Mineralogical Magazine 68, no. 2 (April 2004): 255–77. http://dx.doi.org/10.1180/0026461046820186.

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AbstractMesothermal gold ores in the Archaean Yilgarn Craton of Western Australia are dominated by a pyrite ± arsenopyrite ± pyrrhotite sulphide assemblage. Many of these ores are refractory to varying degrees and require treatment by roasting, bacterial oxidation or finer milling. The most common sulphide ore types can be sub-divided broadly into pyritic (pyrite±pyrrhotite) and arsenical types (pyrite+arsenopyrite± pyrrhotite). Arsenical ores vary from highly refractory to free-milling. Arsenopyrite in highly refractory ores is finer grained, As-deficient (27 –32.5 at.% As), contains high average concentrations of submicroscopic gold (60 –270 ppm), but does not contain inclusions of particulate gold. Arsenopyrite in free-milling ores is coarser grained, less As-deficient to slightly As-rich (30 –35 at.% As), contains low or negligible concentrations of submicroscopic gold, but contains inclusions and fracture fillings of particulate gold. In some refractory arsenical ores, pyrite also contains moderately high levels of submicroscopic gold (20 –40 ppm), the concentration of which is directly related to As content of the pyrite.Pyritic ores are free-milling to mildly refractory, or rarely moderately refractory. Pyrite in pyritic ores contains negligible to low levels of submicroscopic gold (<5 ppm). Other reasons for refractory behaviour in pyritic ores include very fine-grained native gold inclusions in pyrite, or the presence of gold-bearing tellurides.It is concluded that submicroscopic gold is incorporated into the crystal lattices of arsenopyite and arsenical pyrite at sub-greenschist to lower greenschist-facies temperatures, and is progressively expelled as inclusions and fracture fillings of native gold in sulphides, and ultimately into the gangue, as recrystallization proceeds through upper greenschist- into amphibolite-facies temperatures, during deformation and burial. Submicroscopic gold is expelled more rapidly from pyrite than arsenopyrite.Pyrrhotite progressively replaces primary pyrite at higher temperatures, but rarely contains gold. Finally, a metallurgical classification scheme for refractory ores is presented which incorporates the above mineralogical conclusions.

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Bondar, D. B., A. V. Chugaev, Y. S. Polekhovsky, and N. N. Koshlyakova. "ORE MINERALOGY OF THE KEDROVSKOE GOLD DEPOSIT (MUYSKY DISTRICT, REPUBLIC OF BURYATIA, RUSSIA)." Moscow University Bulletin. Series 4. Geology, no. 3 (June 28, 2018): 60–69. http://dx.doi.org/10.33623/0579-9406-2018-3-60-69.

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Ore mineralogy of the largest quartz vein Osinovaya at the Kedrovskoye gold deposit has been studied. Three stages of mineral formation are identified: marcasite-pyrrhotite-pyrite, gold-polysulphide and hypergenic ones. Native gold belongs to gold-polysulfide stage and is represented by two generations. The earlier high fineness (600–870, prevails 780–820) generation cements fragments of pyrite grains and forms inclusions in pyrite, and the later low fineness (520–580, prevails 540–580) generation associates with sphalerite-chalcopyrite-galena veinlets in pyrite. The disappearance of arsenoan pyrite, the increase in iron content of sphalerite, the change of pyrite to pyrrhotite with depth is noted.

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He, Chun Lin, Shao Jian Ma, Xiu Juan Su, and Qiu Hong Mo. "Microwave Roasting Pyrite for Removal of the Sulfur and Arsenic." Advanced Materials Research 881-883 (January 2014): 1531–35. http://dx.doi.org/10.4028/www.scientific.net/amr.881-883.1531.

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The application of microwave technique in the roasting pyrite which contained little arsenic was described. The characteristics of microwave absorption of pyrite were investigated. The results indicated that pyrite was a good absorbent of microwave and heated rapidly to high temperature by microwave flied in a short time, causing decomposition and oxidization to removal the sulfur and arsenic. The effects of microwave irradiation time and sample mass on the removal efficiencies of sulfur and arsenic with microwave power of 4 kW and 6 kW were investigated. The big microwave power could shorten the time for removal of sulfur and arsenic. Finally iron concentrate contained 64.52% Fe, S<0.1%, As<0.094% were obtained.

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Wang, Yongliang, Li Xiao, Ya Liu, Guoyan Fu, Shufeng Ye, and Yunfa Chen. "Alkalic Leaching and Stabilization of Arsenic from Pyrite Cinders." Open Waste Management Journal 10, no. 1 (November 30, 2017): 41–50. http://dx.doi.org/10.2174/1876400201710010041.

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Introduction: Pyrite cinder is one of the important secondary resources, but typically contains a certain amount of arsenic, which is harmful to metallurgical process. It usually hopes to remove the arsenic prior to recycle the valuable element in the pyrite cinders. Methods & Materials: In this study, the arsenic in the cinders was selectively removed using the alkalic leaching method so as to reduce the loss of ferric and other valuable elements. Results & Discussion: The content of arsenic in pyrite cinders was reduced to 0.08% through the investigation of the factors, including particle size, alkaline concentration, temperature, solid-liquid ratio (S/L) and leaching time. Then, the ferric precipitation method was used to remove the arsenic in the leaching solution. More than 99% of the arsenic can be removed by controlling the pH and the ratio of ferric and arsenic (Fe/As) in ambient temperature, and the arsenic concentration in the solution was reduced to less than 0.5mg/L. Conclusion: It was found that the precipitated arsenic was mainly amorphous based on the analysis of sediment.

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Journal articles on the topic 'Arsenian pyrite'

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