Leaching Behaviors of Yulong Refractory Oxide Copper Ores from Tibet in Sulfuric Acid Solutions

摘要

Abstract Yulong copper mine is located in the Changdu region in the eastern mountainous area of Tibetan Plateau, where the elevation of mining area is over 4500?m. At present, the oxide ores from Yulong No. II bodies are refractory to direct agitation leaching in sulfuric acid media under normal leaching conditions. In this research, the mineralogical characteristics of this type of copper ores have been examined using automated mineral liberation analysis (MLA) integrated with scanning electron microscopy. The results showed that this type of copper ores had an extremely high binding rate due to the encapsulation of copper-bearing minerals within gangue minerals, such as kaolinite clay. For the agitation leaching process of Yulong copper ores in sulfuric acid media, the effects of leaching parameters were investigated on copper extraction, aluminum and iron dissolution, respectively. The studied parameters include liquid/solid ratio, agitation speed, leaching temperature, initial sulfuric acid concentration and particle size. The results of kinetic analysis of the leaching data under various leaching temperature indicated that the agitation leaching of copper ores belongs to diffusion control, giving an activation energy of 6.86?kJ/mol for copper extraction, 6.99?kJ/mol for aluminum dissolution and 14.96?kJ/mol for iron dissolution, respectively. Copper recovery from agitation leaching after ball milling as high as 85% was obtained, whereas the direct leaching process resulted in the recovery of only 60% in sulfuric acid solutions. The high-efficiency and low-cost recovery method for this type of oxide copper ore from Tibet Yulong Mines still needs further development in the future.Graphical Abstract