A method for preparation and cleaning of uniformly sized arsenopyrite particles

Journal Article · Sat Oct 11 00:00:00 EDT 2014 · Geochemical Transactions

DOI: https://doi.org/10.1186/s12932-014-0014-9 · OSTI ID:1168806

Parthasarathy, Hariprasad ^[1]; Baltrus, John P ^[2]; Dzombak, David A ^[1]; Karamalidis, Athanasios K ^[1]

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1. Carnegie Mellon Univ., Pittsburgh, PA (United States)
2. National Energy Technology Lab. (NETL), Pittsburgh, PA, (United States)

The oxidative dissolution of sulfide minerals, such as arsenopyrite (FeAsS), is of critical importance in many geochemical systems. A comprehensive understanding of their dissolution rates entails careful preparation of the mineral surface. Measurements of dissolution rates of arsenic from arsenopyrite are dependent on the size and degree of oxidation of its particles, among other factors. In this work, a method was developed for preparation and cleaning of arsenopyrite particles with size range of 150–250 μm. Four different cleaning methods were evaluated for effectiveness based on the removal of oxidized species of iron (Fe), arsenic (As) and sulfur (S) from the surface. The percentage oxidation of the surface was determined using X-ray photoelectron spectroscopy (XPS), and surface stoichiometry was measured using scanning electron microscopy – energy dispersive X-ray spectroscopy (SEM-EDS). Results indicate that sonicating the arsenopyrite particles and then cleaning them with 12N HCl followed by 50% ethanol, and drying in nitrogen was the most effective method. This method was successful in greatly reducing the oxide species of Fe while completely removing oxides of As and S from the arsenopyrite surface. Although sonication and acid cleaning have been widely used for mineral preparation, the method described in this study can significantly reduce grain size heterogeneity as well as surface oxidation, which enables greater control in surface and dissolution experiments.

• Research Organization: National Energy Technology Laboratory (NETL), Pittsburgh, PA, and Morgantown, WV (United States). In-house Research
• Sponsoring Organization: USDOE Office of Fossil Energy (FE)
• Grant/Contract Number: FE0004000
• OSTI ID: 1168806
• Report Number(s): UNIV-PUB--265
• Journal Information: Geochemical Transactions, Journal Name: Geochemical Transactions Journal Issue: 1 Vol. 15; ISSN 1467-4866
• Publisher: American Chemical Society, Geochemistry Div.Copyright Statement
• Country of Publication: United States
• Language: English