Underground leaching of uranium by innovative biotechnological methods
Intensification of the process of underground bioleaching of uranium-based on increased immobilization of bacteria on solid carriers to increase the concentration of uranium in productive solutions and reduce the cost of sulfuric acid.
Problem: Low levels of ferric iron are present in the leaching solutions of the mines. To increase the content of ferric iron in the mine, a specialist uses hydrogen peroxide, which significantly increases the cost of the process.
Solution: At the first stage of the work, we conducted a complex of studies for a uranium mine laboratory, sampling with bacteria, studying the kinetics of the process in laboratory conditions on models and production solutions. As a result, unique data on the temperature regimes of operation, the modes of bacterial reproduction. Bacteria adapted to mine solutions proliferate actively without the need for regular additions. At the second stage of the work, an experimental setup tested the application of biotechnological methods directly on mine solutions. The installation with a volume of up to 500 m3 for industrial promotion can provide the necessary degree of transition of ferrous iron to ferric. The installation in the container assembly was delivered to the mine and put into operation. During the tests, we investigated several options of creating a technological scheme. Laboratory data has confirmed the effectiveness of the process of the transition of ferrous iron in solution to the ferric form. To achieve the kinetics of the process, we used innovative methods using an increased concentration of bacteria in the work. This allowed several times to increase the flow of solution through the installation, which is of fundamental importance for the industrial implementation of the project.
Economic efficiency: Biotechnological methods for underground leaching will allow:
● increase the uranium content in productive solutions by 1020%,
● reduce the consumption of sulfuric acid by 515%,
● increase the redox potential of solutions.