Standard Test Method for Determining the Rate of Bioleaching of Iron From Pyrite by Thiobacillus Ferrooxidans (Withdrawn 2010)

The development and refinement of processes for bioleaching of metal ores and coal desulfurization require intercomparison of bioleaching data both to better understand metal ore bioleaching mechanisms and to develop more effective strains. For uncertain reasons, different strains of T. ferrooxidans exhibit different pyrite leaching rates and different sources of pyrite vary widely in susceptibility to microbial attack.

This test method has been developed to provide a standard procedure for evaluating the rate of bioleaching of iron from iron pyrite (FeS₂), a commonly used growth substrate for T. ferrooxidans and an important mineral that is biologically degraded in commercial bioleaching operations and in many exposed coal deposits. A high leaching rate in this test is evidence for potential degradability of the mineral in mining operations. A low rate of bioleaching suggests that the mineral is inherently not a good substrate or that it contains toxicants toward thiobacilli, and might not be readily bioleaching in a mining operation.