Improvement of metals leaching optimal parameters from technogenic waste dumps with using mesophilic association of acidophilic chemolithotrophic bacteria

Abstract

The results of improving the standard parameters of the process of bacterial leaching of metals, which allow to shorten the term of carrying out technological process and increase the efficiency of the extraction of germanium and other useful components are provided in article. To achieve the goal the mineralogical and chemical analysis of waste dumps have been made and the composition and leaching potential of the main groups of microorganisms of waste dumps were established also. Bacterial leaching was carried out using the mesophilic association of acidophilic chemolithotrophic bacteria, which are characterized by a high level of leaching activity. To determine the optimal parameters of the biotechnological process were compared results obtained with used: standard 9K medium with ferrous iron as an energy source; at constant elevated values of the oxidation-reduction potential at the level of 0.650 V; with ferric iron as an oxidizing agent, and using an optimized nutrient medium (OPM), the composition of which has been determined on the basis of mathematical optimization. The obtained results showed, that the using of ferric iron, OPM and elevated values the oxidation-reduction potential allow to shorten the term of leaching process and increase the recovery of germanium and other metals by 2 to 5 times. Moreover, the advantage of leaching with OPM is the absence of iron ions, which are an impurity and interfere with further sorption recovery of germanium from polymetallic solutions to produce germanium concentrate. Thus, optimum process parameters of bacterial leaching of metals, allows using them depending on the conditions and needs receiving of the targets metals from waste dumps.