Folk Copper Bacterial Leaching Pilot Study

Biohydrometallurgy is a discipline of hydrometallurgy, which values the use of the metabolism of microorganism, principally Thiobacillus ferrooxidans, Leptosoirillum ferrooxidans and thennophilic species of Sulfobacillus, Acidianus and Sulfolobus to leach a metal of value such as copper, zinc, uranium from a sulfide mineral. Compared with traditional smelting technologies, biotechnology has the advantages of lower energy expense and capital and operating cost, using resource fully, rebust process. Moreover, it can be applied to treat refractory or low-grade ores, which challenges traditional technologies. Nowadays, a large quantity of bioleaching operations has been applied all over the world. In this thesis, bioleaching has been applied to low-grade copper ores from Minle Copper Mine, Jinggu, Yunnan. In the course of research, several types of experiments have been deserved to determine the optimum leaching conditions, which leads to industrial application.The process mineralogy of the ore samples from Songjiapo district of Minle Copper Mine has been studied to make the conclusion that the copper mineral within the ore are copper sulfides, mostly chalcocite(>99%).By activity mensuration, the most active strain of Thiobacillus Ferrooxidans has been screeened out from several different cultivated strains to apply to the further study. The strain has then been domesticated in the pulp with ore samples in a certain condition of pH. temperature, and bacteria population. With increasing of the pulp density, the strain adapts to the ore, whose activity has been strengthened.Several experiments have been deserved, which are shaking flask leaching, aerated, stirred-tank leaching (in the presence and absence of bacteria) and column leaching, respectively. The results demonstrated as following:1. Copper recovery of the bioleaching is higher than acid leaching, which was up to 94%;2. Leached for 227 days, copper recovery of ore samples of-10+5mm was 74.14%.that of-20+10mm was 39.69%, which proved that ore from Minle Mine suited for bioleaching;3. Little reagents are needed in the leaching operation except for sulfuric acid using for adj usting pH of the solution;4. Ore grind size is an important parameter in the operation.5. Further copper recovery can be achieved from residue of industrial acid leaching process.The mechanism of chalcocite bioleaching has been researched to determine that the mineral CuS would be produced as mediate product in the course of reaction, which agrees to the conclusion of most literatures.