Transactions of Nonferrous Metals Society of China
JOURNAL OF RAILWAY SCIENCE AND ENGINEERING
|Vol. 18 No. 6 December 2008|
（School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, China）
Abstract:Oxidation of arsenopyrite with Acidithiobacillus ferrooxidans was studied. The electrochemical results show that arsenopyrite is firstly oxidized to As2S2 at the potential of 0.2−0.3 V (vs SHE) and As2S2 covers the electrode and retards the process continuously. While at higher potential over 0.3 V (vs SHE), As2S2 is oxidized to H3AsO3, and H3AsO3 is then oxidized to H3AsO4 at 0.8 V (vs SHE). The leaching results show that the addition of FeS2 can promote the oxidation of As3+ to As5+ and increase the activity of the bacteria. The best bio-oxidation technical parameters are the initial pH of 1.8−2.0, particle sizes less than 0.074 mm, temperature in the range of 25−30 ℃ and rotating speed of the orbital incubator of 100−160 r/min. The results provide theoretical and technological supports of bio-oxidation arsenopyrite for pretreating refractory arsenic gold ores.
Key words: arsenopyrite; electrochemistry; bio-oxidation; Acidithiobacillus ferrooxidans