| Since lithium-ion batteries (LIBs) were first produced by Sony in 1991, these batteries are extensively used as electrochemical power sources in mobile telephones, personal computers, video-cameras and other modern-life appliances due to their favorable characteristics of high energy density, light weight and good performance. With the wide utilization and consumption of LIBs, there are amounts of spent lithium-ion batteries produced which are harmful for the environment. Therefore, the development of novel recycling technology of spent LIBs has become an hotspot problem from the viewpoint of environmental protection and resource conservation.In this study, according to the constituent characteristics of the spent LIBs which came from the factory in Xiangtan city, the flow sheet consisted of the following processes:stirring scrubbing and dilute acid leaching with stirring scrubbing were used to separate the active materials from current collectors, leaching of the active materials with H2SO4 +H2O2 was investigated after incineration, separating copper by extraction－precipitating iron in sodium jarosite form－precipitating aluminium with NH4HCO3－the advanced removal of the residual impurities by P204 solvent extraction－the separation of Co and Ni by P507 solvent extraction－precipitating cobalt with (NH4)2C2O4.Stirring scrubbing and dilute acid leaching with stirring scrubbing were used to separate the active materials from current collectors, copper and aluminum here were recovered with the metallic form. The carbon powder was completly removed by the incineration.The active materials was lixiviating by sulphuric acid and hydrogen peroxide. To obtain the optimized leaching conditions of the mixture powder, the following operational variables and levels were performed in time and temperature, various sulfuric acid and hydrogen peroxide concentration, liquid-to-solid ratio, respectively. A leaching efficiency of more than 95% of Ni, Co and Mn could be achieved at optimum conditions. Extraction of copper from this leach liquor was carried out with the extractants N902. The removal rate of Cu achieved 99.5%, and the optimum extraction and stripping technical conditions were determined through the single factor experiments; The method of ferrum-removal by sodium jarosite was adopted, of which the content of Co in the residue was low and the removal rate of Fe was over 99.9%; Aluminium is removed by precipitating with NH4HCO3, the removal efficiency of aluminium reaches 98%, almostly, while the loss rate of cobalt is less than 2%Solvent extraetion was utilized here for the advanced removing of the residual impurities and the advanced separation of Co and Ni. P204 was selected as the extractant for the advanced removal of impurities. Through the study on the single factor such as equilibruim pH, phase ratio, scrubbing stage, stripping acidity. The optimum technical conditions were determined. It's proved that the excellent effect of the extractant P204 for the advanced purification of Co and Ni solution under the optimum conditions. Then, the extractant P507 was utilized to separate Co and Ni. The result of the experiment showed the excellent effect on separation of Co and Ni, which benefited the subsequent proeess, i.e. the preparation of high purity metals cobalt compound. Finally, cobalt was chemically deposited as oxalate from the strip liquor.This hydrometallurgical process is found to be simple, the final purity of cobalt oxalate was at least 99%. This process will contribute a new teehnical scheme to the industrialized practice and production. |
PDF Full Text Request