Study of the Effect of Endemic Microorganisms from a Copper Deposit on the Efficiency of Sulfuric Acid Leaching

This paper presents the results of testing a copper bioleaching technology applied to two types of ore sampled from different sections of deposits within one of the deposits in the Balkhash region. Preliminary microbiological studies of microorganisms present in mineral raw material samples from the deposit revealed that, under conditions favorable for the growth of iron- and sulfur-oxidizing bacteria, active proliferation of yeast-like fungi was also observed, along with a bacterial culture identified as Skermanella aerolata. Preliminary experiments demonstrated that the effect of the identified bacterial culture, in association with A. Ferrooxidans and A. Thiooxidans, positively influences oxidative processes involved in the decomposition of sulfur- and iron-containing minerals. The complete consortium of endemic microorganisms used in bioleaching experiments exhibited the highest efficiency compared to both individual cultures and the conventional sulfuric acid leaching method. The effect of biological oxidation on a simple-composition ore sample resulted in a 5.4% increase in copper recovery, while the efficiency of sulfuric acid consumption improved by nearly 40%. The use of bacterial oxidation for a low-grade, high acid-consuming ore sample showed comparable copper recovery; however, sulfuric acid consumption was reduced by a factor of 2.5.