| Copper resources which are uesd in important fields such as national defense,building materials and electic and provide important support for the development of the nationnal economy are crucial strategic resources for mineral products in China.At present,China's degree of dependence on foreign trade of copper resources are up to 70%.China faces huge potential mineral risks.With the continuous exploitation and utilization of easy-selected copper mines,the proportion of refractory copper mines is gradually increasing.But the treatment of refractory copper mines lacks efficient technology.Therefore,the research and development of new technologies for the efficient recycling of refractory copper mines in domestic is extremely important and imminent.The copper oxide ores which belong to typical refractory copper oxide ores with high oxidation rate,high combination rate and high calcium and magnesium content are selected from Dali Yunnan Province as the research object in the paper,containing about 2.20%copper,88.80%copper oxide,60.11%binding copper,20.80%MgO and CaO.The results show that the copper ore is a refractory copper oxide ore.A large amount of literature indicates that the main methods for processing such copper ore are flotation,hydrometallurgy and combined process of beneficiation and metallurgy.While the flotation method and ammonia leaching method have very low copper recovery rate,resulting in serious waste of resources.Therefore,The process of“acid leaching–extraction–electrowinning”is selected to treat the copper oxide ore in the paper.The process technology has obtained the ideal technical index of copper leaching rate of 90.83%,copper extraction rate of 99.70%,copper stripping rate of98.36%,and cathode copper purity of 99.95%.The paper draws the following conclusions through studies on leaching kinetics,leaching,solvent extraction and electrowinning tests:?1?The acid leaching kinetics analysis showed that the leaching process accorded with the“shrinking unreacted core model”,and the diffusion across the product layer is the rate-controlling step.The kinetic equation is in accordance with1-2/3a-?1-a?2/3=Kt.The apparent activation energy of the leaching process was11.43 kJ/mol.?2?The acid leaching test showed that the main factors affecting copper leaching rate are:sulfuric acid concentration?liquid-solid ratio?stirring strength?grinding fineness?leaching time and temperature.The CCD response surface model was established by single factor conditional test,and the leaching conditions were further optimized.The optimum leaching conditions were:normal temperature and pressure,sulfuric acid concentration of 13%?liquid-solid ratio of 2.5:1?stirring intensity of300r/min?grinding fineness of the ore in-0.074mm accounted for 40%and the leaching time was 120 min.The copper leaching rate obtained under this condition was 90.83%.?3?Extraction pH?value?1.9?,strict regulation of the pH value of the leachate is beneficial to the extraction operation.The pH adjustment of the leachate can be achieved by pre-reacting a part of the raw material with the leachate.?4?M5640 is an effective extractant for this leachate.The optimum extraction conditions are extractant concentration of 10%,phase ratio of 1:1?extraction time of 3min and two-stage countercurrent extraction,copper extraction rate can reach 99.70%;the best stripping conditions are:sulfuric acid concentration of 180g/L?stripping phase ratio of 1:1,stripping time of 3 min and the two-stage countercurrent stripping,the copper stripping rate is 98.36%.?5?Electrowinning experiments show that:adding appropriate amount of Gul glue can obtain a smooth,flat surface cathode copper,which purity?value?99.95%?. |
PDF Full Text Request