Microbial Community Succession Laws Of Pb, Zn, Sn Complex Copper Concentrate Tank Leaching

Bioleaching of chalcopyrite has been the problem of the field of hydrometallurgy. This article use the moderately thermophilic bacterias leaching the chalcopyrite at45℃, record the concentration of copper ions in the leaching solution of the leaching process. Use the restriction fragment length polymorphism analysis the16S rDNA sequence of different types leaching bacterias. Research the microbial community succession laws in the leaching solution.Bioleaching bacteria used in this experiment are Acidithiobacillus caldus、Leptospirillum ferriphilum and Sulfobacillus thermosulfidooxidans. Optimize the growth conditions before use them to leaching chalcopyrite, and carried high concentrations of chalcopyrite concentrate tolerance domestication. After a series of growth conditions optimization experments, get the optimum culture conditions:growth temperature are45℃、pH1.5、and0.6g/L peptone. After7days of shake flask culture, the highest bacteria concentration of8.0×108/mL,when use the stirred reactor only need5days, the highest bacteria concentration reach1.0×109/mL. After make sure the optimum culture conditions, begin the high concentrations of chalcopyrite concentrate tolerance domestication. After several generations of different concentrations of chalcopyrite pulp domestication, moderately thermophilic bioleaching bacteria grow well in100g/L chalcopyrite pulp within30days of copper leaching rate of80%. Compared with the untamed moderately thermophilic bacteria (100g/L of slurry concentration, the leaching rate of only30%), the moderately thermophilic bacteria after domestication have improved in th highest bacteria concentration and the leaching rate of copper. Through the validation of the two sets of parallel experiments, indicating that the moderately thermophilic bacteria mixing in a stirred reactor leaching of chalcopyrite concentrate optimum mixing speed is350r/min, the intensity of the optimal inflation is500mL/min.Domesticated moderately thermophilic bacteria in the optimun leaching conditions leaching the chalcopyrite, stirring after30days of leaching, the copper ion concentration of17.36g/L, the copper leaching rate was85.6%.Sampling from the leach solution at three time points (7th day,17th day and27th day), using RFLP technique analysis on different types of leaching bacteria16S rDNA sequence, the evolution of the microbial communities in the leaching solution in the comparison of different leaching time. The study found that in the three samples the three bacterias(Acidithiobacillus caldu, Leptospirillum ferriphilu, Sulfobacillus thermosulfidooxidans) all exist. Samples of seventh day, At.caldus proportion reached73.8%. At17th day, bioleaching microbial community composition was greatly changed, S.thermosulfidooxidans the proportion rose to52.4%, to become the dominant strain. This trend has continued to the end of leaching, S.thermosulfidooxidans proportion rose to66.7%at27th day.