| Gold is a precious metal that plays an important role in society and the economy.Wet leaching is usually used to extract gold from gold deposits,and cyanide leaching of gold has been adopted by most gold mining enterprises because of its high leaching efficiency.But cyanide leaching gold has high chemical consumption and toxicity,which is harmful to the environment.Biorefinery has become a new method for gold leaching due to its environmental friendliness.In this paper,Bacillus megafilus was selected as the bacteria for microbial leaching in Fanzhi gold mine.Based on the process mineralogy analysis of Fanzhi gold mine,the bacteria were cultured and tamed,and the optimal parameters of bacterial domestication were obtained.Then,the single factor experiment was used to investigate the bioleaching and optimization process of gold ore,and the correlation analysis was made on the bioleaching mechanism and ecological evaluation of gold ore,which provided a new idea for bioleaching of gold.The growth curve of Bacillus megacarum culture showed that Bacillus megacarum had good activity in the first cycle.During the second cycle,the activity of the bacteria decreased significantly.In the third cycle,the activity of Bacillus megacarba had been greatly reduced and the growth of the bacteria slowed down.The results indicated that the activity of Bacillus megathiensis showed an obvious linear declining trend with the passage of time.The results of leaching gold ore by Bacillus megacarbium show that the highest leaching rate of gold ore is 91.47% under the conditions of grinding particle size of200?300 mesh,ore liquid ratio of 10g/L,glycine concentration of 12g/L and p H value of 9.5.On this basis,through process optimization,when the ratio of addition liquid to leaching liquid is 75 m L /L,and the ratio of glycine to addition liquid is 0.1g/ m L,the gold ore leaching rate increased and reached to 98.25%The gold leaching mechanism of Bacillus megacephala is that the cyanogen producing microorganism Bacillus megacephala can produce the secondary metabolite hydrocyanic acid through its own metabolism.This king of hydrocyanic acid complexes with the gold in the mineral,to form a soluble gold cyanide complex,which dissolves the gold in the mineral into the leaching solution.The results of ecological evaluation and analysis on the leaching of gold by Bacillus megacarum showed that the gold leaching environment was not suitable for the growth of Bacillus megacarum on the whole.The activity of Bacillus megacarum could be effectively enhanced through the improvement of additive experiments,which improved the cyanide production efficiency and indirectly increased the leaching rate. |
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