Approaches to uranium dump processing by bioleaching technology

Abstract

This paper discusses a method of extracting uranium from uranium dumps by bacterial leaching using association of thion bacteria. Bioleaching mechanism is based on interaction of biological, chemical and electrochemical processes. The microstructure and composition of uranium-containing wastes were also investigated. The work presents the results of the study (changes in volumetric activity) before and after leaching. Results of the research proved that at microbiological processing of uranium production waste by association of thionic bacteria the degree of uranium leaching out of dumps at pachuca leaching was 59.3%. Nevertheless the residual radioactivity allows classifying the obtained material to be low-level radioactive waste one. At percolation leaching, having the aim to determine the effect of particle size of feed stock on the degree of uranium extraction, two samples were under study: breakstone in initial condition and ground breakstone. According to results of the study the degree of uranium extraction (a grinded one 0.3-0.5mm fraction) from dumps is 35.18%. Using breakstone in initial condition (10-25 mm fraction) degree of uranium leaching from dumps at percolation leach-ing measures up to 100%. Thus, residual radioactivity corresponds to all national sanitary standards for classifying a solid phase to a nonradioactive one. In addition, using microbial leaching there’s no need in further uranium ore grinding and that reduces costs to process ura-nium dumps. The work proposes a scheme for processing uranium dumps in the technological process. This technology will contribute to transforming the places for uranium waste storage into anthropogenic deposits.