SUPPRESSION OF MICROBIAL PYRITE OXIDATION BY FATTY-ACID AMINE TREATMENT

Numerous techniques have been investigated in the past for the treatme nt and control of acid mine drainage (AMD). While some of these techni ques are directed towards the treatment of the resulting drainage, oth ers are directed towards the prevention of AMD at-source. The at-sourc e prevention methods have been found to be promising since, if achieve d, they can provide permanent solutions to AMD problem. However, thoug h the bacterium, Thiobacillus ferrooxidans plays an important role in the formation of AMD, and is unavoidable in AMD systems, many of the a t-source AMD control and prevention techniques have not been evaluated in the presence of this bacterium. In this study, the stability of fa tty acid amine (FAA) treated pyrite in the presence of T. ferrooxidans was investigated. The rate limiting reactions during the oxidation of pyrite, in the absence and presence of the bacterium, was also invest igated. The FAA treatment reduces the rate of both the chemical and bi ological oxidation of the pyrite. In the absence of the bacteria, ferr ous to ferric ion oxidation is the rate limiting reaction in pyrite ox idation, while in its presence, ferric oxidation of pyrite is the rate limiting reaction.