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Optimization of bacterial leaching of pyrite in coal. Final report

Technical Report ·
DOI:https://doi.org/10.2172/5722369· OSTI ID:5722369

This report presents an account of research dealing with the solubilization of pyrite in coal by ferric ions regenerated through bacterial action. The original plan of investigation set out a number of areas in which information was to be obtained relevant to the basic question: Can enhancement of the rate of bacterial oxidation of ferrous ions in a recirculated leaching system result in rapid removal of pyrite from coal. As work proceeded it became evident that the rate of pyrite removal in the systems under investigation was rarely limited by the rate of reoxidation of iron, but rather by the rate of reaction of the dilute ferric solutions with the pyrite in coal. In some cases, the bacterial reoxidation of ferrous ions, in lixiviant solutions, resulted in the deposition of jarosite, which left the leached coal particles coated with an oxidized iron residue containing sulfur, thereby diminishing net sulfur removal as well as retarding pyrite oxidation. Accordingly, a portion of our effort was directed toward understanding the process of jarosite deposition and in seeking practical means by which this product could be removed from leached coal and either disposed of or utilized as a by-product of the leaching process.

Research Organization:
State Univ. of New York, Binghamton (USA). Dept. of Biological Sciences
OSTI ID:
5722369
Report Number(s):
FE-2749-T1
Country of Publication:
United States
Language:
English