Effect And Mechanism Of Different Ions Stress On Bioleaching Of Chalcopyrite

During the process of chalcopyrite bio leaching, the gangue minerals which associated with chalcopyrite will be dissolved in ionic form under the microbial and chemical effects of the leaching system. The research on influence of the dissolution ion exerts on the Acidithiobacillus ferrooxidans (for short Ai.f) and the copper leaching rate have been reported rarely. The influence rules of the single cation (potassium, magnesium, calcium, aluminum), silicon disso luted from the quartz with cations, and the ions dissoluted from the combination of quartz-sericite, quartz-dolomite, quartz-fluorite, quartz-apatite, quartz-calcite exerts on the bacterial oxidation activity and copper leaching rate of 9K medium system and chalcopyrite leaching system were studied respectively. In the meanwhile, the influence mechanism of different ions stress on chalcopyrite bio leaching was revealed.The study found that in the 9K medium system, the promoting influence extent of single cations on At.fbacterial oxidation activity was:calcium> potassium>aluminum> magnesium; While in the presence of silicon dissoluted from quartz, the influence sequence was in line with the single cations; Under the stress of ions dissoluted from the combination of gangue minerals, the promotion was the strongest on the bacterial oxidation activity with the combination of silicon-calcium-magnesium. However, in the chalcopyrite bioleaching system, after leaching 45 days, the influence sequence on copper leaching rate of single cation was:aluminum> magnesium> potassium> blank> calcium, and the copper leaching rate up to 71.39% under the stress of aluminum. In the presence of silicon dissoluted from quartz, calcium stress had the largest promoting effect on copper leaching, and the copper leaching rate up to 71.71%, followed by aluminum>magnesium>potassium. Under the stress of combination of gangue mineral dissolution ions, in the presence of silicon-aluminum-potassium dissoluted from quartz-sericite significantly improved the copper leaching, and the copper leaching rate up to 59.55%; While in the presence of silicon-calcium-phosphate dissoluted from quartz-apatite inhibited the copper leaching in greatest degree, and the copper leaching rate only 27.49%.Under the stress of ions dissoluted from different gangue minerals, the XRD analysis of the chalcopyrite bioleaching residue revealed that the jarosite or ammoniojarosite generated in the leaching system under the stress of single cation, silicon with cation, silicon-magnesium-calcium, silicon-calcium-fluorine, silicon-calcium-phosphate; While the calcium sulphate and brushite generated in the leaching system with calcium, the oolite chlorite and copper hercynite generated under the stress of silicon-aluminum-potassium, the calcite appeared in the presence of silicon-calcium-phosphate and silicon-calcium-carbonate. And the sediments absorbing on the surface of chalcopyrite hindered the copper leachingSEM-EDS analyses of the bioleaching residue revealed that the surface of chalcopyrite particles after leaching showed different degrees of corrosion in the presence of different ions. A linear relationship was observed between the decreased order of the weight proportion and atomic number proportion of Cu and the copper leaching rate in the presence of different ions. AFM found that, corrosion phenomenon of the chalcopyrite particles surface was the most serious under the stress of aluminum, and the corrosion quantitative analysis found that the surface of chalcopyrite corrosion situation was not only judged by roughness. Under the stress of different ions, infrared spectrum and Zeta potential changes could be very good to explain bacterial strength in chalcopyrite surface adsorption, revealing the influence mechanism of differences of chalcopyrite bioleaching.