Metal Electrochemical Recovery And Process Research Of Waste Lithium Ion Batteries

The spent lithium ion battery not only has a high content of valuable metals such as copper,cobalt,nickel,but also components such as LiCoO₂ and LiPF₆ which are likely to pollute the environment and endanger human health.With the rapid growth of lithium-ion battery production and the large number of waste lithium-ion batteries,spent lithium-ion batteries have high recycling value from the perspective of environmental protection and resource recycling.In order to reduce the amount of acid,create an environment-friendly and safe environment,and improve the leaching rate of metal,a bacterial strain ESY06 with the properties of high efficiency and high tolerant metals,identified as Thiobacillus ferrooxidans?T.f.?,was obtained by the method of isolating and cultivating a long term.The bioleaching of three kinds metals of copper,cobalt and nicke in spent lithium ion batteries by strain ESY06were investigated,including the effect of different concentrations of Fe²⁺on the growth of a strain ESY06.The results showed that the tolerant ability of strain ESY06 to copper,cobalt and nickel was respectively 1224.78 mg/L,2213.93 mg/L and 289.62 mg/L;When Fe²⁺concentration was 20 g/L,the growth of strain ESY06 was the best.The leaching rate of copper,cobalt and nicke in mixed electrodes can reach 99.88%,99.93%and 99.55%respectively.The combined process of acid leaching pre-treated and bioleaching has good effect on copper,cobalt and nickel recovery,and has advantages in recovering valuable metals from battery electrode materials.In order to increase the added value of copper,copper containing solution by edulcoration and extraction separation was treated by electro-deposition method and copper was recovered at cathode simultaneously.The effect of Electrode materials,voltage,electrodepositiontime,electrodepositing temperature and additives on Cu²⁺copper recovery were investigated.The recovery rate of copper can reach 99.26%at the best technological conditions.In order to further understand the kinetics of copper electrodeposition,electrochemical reduction of manganese Cu???on copper electrode was researched by cyclic voltammetry?CV?and linear sweep voltammetry?LSV?.The results showed that under-0.2 V and-0.4 V scanning potential,the apparent activation energy?G of the reaction is 15.77 KJ/mol and 12.48 KJ/mol respectively.The mixed additive of Cl^-,thiourea and gelatin can polarizing the deposition of copper,and can inhibit copper electrodeposition and hydrogen precipitation.The extraction conditions of cobalt and nickel were studied by Cyanex272,and high purity cobalt sulfate crystals were obtained by evaporation crystallization.The experimental results show that the extraction rate of cobalt is 99.06%and the loss rate of nickel is2.43%when the pH value of water phase is 3,the concentration of cobalt is 8 g/L,the O/A is 1and the Cyanex272 is 15%.When the dilute sulfuric acid of 0.075 mol/L was applied as the stripping agent,recovery rate of copper was more than 98%.