Experimental Research Of Bioleaching Of Heavy Metals From Mine Tailing By Indigenous Thiobacillus Ferrooxidans And Indigenous Thiobacillus Thiooxidans

The mining and metallurgical activities that were particularly intensive during the last century resulted in the generation of huge amounts of mine tailings, including acid-generating sulfidic tailings. Mining of mineral ore and disposal of resulting waste tailings pose a significant risk to the surrounding environment. The improper management in the past resulted in the migration of heavy metals to the surrounding environment.Previous studies demonstrated that the bioleaching of mine tailing by microorganisms was an efficient "green technology" for heavy metals removal, which has the advantages of low cost and environment friendliness and better efficiency. In this paper I carry out bioleaching expentment of mine tailing from a tailing dam in Yongzhou by indigenous indigenous Thiobacillus ferrooxidans and indigenous Thiobacillus thiooxidans to provide an alternative method for heavy metals in tailings disposal and remediation of polluted soil.The effectiveness of bioleaching is highly dependent on the physical, chemical and biological factors. The choice of leaching bacteria of contaminated material and composition of the medium are the important factors because they control the two key bioleaching reaction, the time and running costs. A complete understanding of the factors that affect the bioleaching process was very important to optimize the bioleaching process. In order to reduce response time and cost, the appropriate leaching bacteria and the corresponding concentration of energy source to soil solids concentration are very important.The laboratory results of the experiment demonstrate that the indigenous bacteria have high value of bioleaching and can be used in removing heavy mental from mine tailings. In certain conditions, taking appropriate bacteria for different heavy metals can get better results, change the heavy metals and reduce the concentration of heavy metal pollutants:The optimal bacteria for bioleaching of Zn were the indigenous Thiobacillus ferrooxidans with the solubilization efficiency at98.12%. The optimal bacteria for bioleaching of Cu were the mixture of indigenous Thiobacillus ferrooxidans and Thiobacillus thiooxidans with the solubilization efficiency at88.75%. For further study of leaching process of interaction and to determine the impact of different energy source, I select the mixed bacteria in the process of dealing with the tailings of different sulfur and ferrous ions respectively. Through experiments we found that when mixed bacteria bioleaching of tailings, indigenous Thiobacillus ferrooxidans and indigenous Thiobacillus thiooxidans implact each other:When the sulfur content of the substrate in the process of leaching the decisive role of copper, the sulfur content of the substrate with the increase in copper leaching effects of first decreased and then increased, the substrate sulfur content of3%to obtain the best removal rate of83.79%. To zinc metal, the sulfur content of the substrate with the increase of zinc leaching results showed declining trend, when the sulfur content of the substrate is0, the maximum removal of zinc, to82.52%; When the substrate iron ions play a decisive role in the process of leaching time on copper, the substrate with increasing the content of ferrous ions, copper leaching effect reaches a certain value remained stable, when ferrous ions The key content of0.5%. To zinc metal, the substrate with increasing concentrations of ferrous ions, zinc leaching results show gradual upward trend, the substrate ferrous iron content is3%, the highest removal rate of zinc.