TY - JOUR
T1 - Arsenopyrite oxidation
T2 - A review
AU - Corkhill, C. L.
AU - Vaughan, D. J.
N1 - Funding Information:
This research was supported by an EPSRC doctoral training Grant to Claire L. Corkhill and by funding from NERC to David J. Vaughan. The authors wish to thank Don Rimstidt, Pierfranco Lattanzi and Antonella Rossi for their invaluable comments and suggestions during the review process.
PY - 2009/12
Y1 - 2009/12
N2 - Arsenopyrite (FeAsS) is the most common As-bearing sulfide mineral. Under oxidising conditions, such as those in mine waste systems, it breaks down to release acids of As and S into the environment, resulting in acid mine drainage with high concentrations of dissolved As. In this communication, current knowledge of arsenopyrite oxidation is reviewed based on a survey of the existing literature, which has focused on processes and reactions at the mineral surface. X-ray photoelectron spectroscopy (XPS) has shown that the oxidation of arsenopyrite in acid is more rapid than in air, water, or in alkaline solutions. Oxidation products reported by XPS include Fe(III) oxide, As(III), As(V), SO32 - and SO42 -. The elemental constituents of arsenopyrite oxidise at different rates, although there is no consensus as to which is the fastest or slowest to oxidise. Electrochemical studies have highlighted the formation of elemental S on the arsenopyrite surface, while XPS studies suggest that only oxy-anions of S form. Kinetic studies of arsenopyrite oxidation suggest that O2 and Fe3+ are the dominant inorganic agents causing arsenopyrite dissolution. The bacterially-mediated oxidation of arsenopyrite by acidophilic Fe- and S-oxidising bacteria such as Acidithiobacillus ferrooxidans and Acidithiobacillus caldus, is more extensive than abiotic oxidation. The literature pertaining to arsenopyrite oxidation is divided regarding the reaction stoichiometry, and the composition and layering of surface overlayers.
AB - Arsenopyrite (FeAsS) is the most common As-bearing sulfide mineral. Under oxidising conditions, such as those in mine waste systems, it breaks down to release acids of As and S into the environment, resulting in acid mine drainage with high concentrations of dissolved As. In this communication, current knowledge of arsenopyrite oxidation is reviewed based on a survey of the existing literature, which has focused on processes and reactions at the mineral surface. X-ray photoelectron spectroscopy (XPS) has shown that the oxidation of arsenopyrite in acid is more rapid than in air, water, or in alkaline solutions. Oxidation products reported by XPS include Fe(III) oxide, As(III), As(V), SO32 - and SO42 -. The elemental constituents of arsenopyrite oxidise at different rates, although there is no consensus as to which is the fastest or slowest to oxidise. Electrochemical studies have highlighted the formation of elemental S on the arsenopyrite surface, while XPS studies suggest that only oxy-anions of S form. Kinetic studies of arsenopyrite oxidation suggest that O2 and Fe3+ are the dominant inorganic agents causing arsenopyrite dissolution. The bacterially-mediated oxidation of arsenopyrite by acidophilic Fe- and S-oxidising bacteria such as Acidithiobacillus ferrooxidans and Acidithiobacillus caldus, is more extensive than abiotic oxidation. The literature pertaining to arsenopyrite oxidation is divided regarding the reaction stoichiometry, and the composition and layering of surface overlayers.
UR - http://www.scopus.com/inward/record.url?scp=70350619339&partnerID=8YFLogxK
U2 - 10.1016/j.apgeochem.2009.09.008
DO - 10.1016/j.apgeochem.2009.09.008
M3 - Review article
AN - SCOPUS:70350619339
SN - 0883-2927
VL - 24
SP - 2342
EP - 2361
JO - Applied Geochemistry
JF - Applied Geochemistry
IS - 12
ER -