Significance of jarosite dissolution from the biooxidized pyrite surface on further biooxidation of pyrite

Abstract

Coal-derived pyrite biooxidation using Acidithiobacillus ferrooxidans is a principal method for coal desulfurization. However, jarosite synthesized in the pyrite biooxidation system can get distributed on the pyrite surfaces and inhibit pyrite biooxidation. In this study, K-jarosite, NH4-jarosite, and Na-jarosite biosynthesis was studied in liquid systems. Then, quick dissolution of K-jarosite was investigated at pH0.2–1.0, and pyrite biooxidation efficiency before and after jarosite removal from the biooxidized pyrite surface was examined. The results showed that pure K-jarosite was collected from K-jarosite biosynthesis system. However, the minerals harvested from NH4-jarosite and Na-jarosite biosynthesis systems were a mixture of jarosite and schwertmannite. The K-jarosite dissolution efficiency reached 46.0% and 78.4% at 48h when the initial pH of dissolve system was 1.0 and 0.2, respectively. Moreover, jarosite removal from biooxidized pyrite surface by rapidly dissolving could enhance iron and sulfur dissolution from pyrite in the subsequent biooxidation process.