Affiliation:
1. Chinese Academy of Sciences
Abstract
Abstract Orpiment (As2S3) is one of the major arsenic sulfide minerals, which can be dissolved by ferric ion and proton produced by the bacteria, and the main intermediates were polysulfides and elemental sulfur. In this study, two strains (Acidithiobacillus thiooxidans and Acidthiobacillus caldus) were used to bioleach the orpiment without iron ions addition. The experimental results show that both the two strains can grow in the pulp and dissolve the orpiment. In the bioleaching, it was found that pH decreased, the concentration of arsenic increased significantly and no elemental sulfur is detected on the surface of the residuals. At the same time the density of the planktonic bacteria increased obviously. These results indicate that the orpiment can be dissolved by the bacteria easily in absence of Fe3+. This study suggests that the release of arsenic which is from orpiment in the mining tailings can be faster than expected in open air.
Publisher
Trans Tech Publications, Ltd.