Recovery Of Cobalt From Cathode Materials Of Waste Lithium-ion Batteries

The widespread use of handheld devices such as mobile phones and portable computers has contributed to a large increase in the production and use of lithium-ion batteries,but the service life of lithium-ion batteries was only a few years,so the production of lithium-ion batteries in China is increasing every year.If lithium-ion battery was be abandoned without harmless treatment,it will not only cause great pollution to the environment,but also harm the health of human beings greatly.At the same time,waste lithium-ion battery contains a lot of valuable metals,especially cobalt,it has great value to realize the recovery and reuse of valuable metal resources in waste lithium-ion battery.This study selected 18650 lithium-ion battery,this type of battery is widely used in portable notebook computers.First of all,the waste lithium-ion battery was discharged and dismantling,then the cathode material of dismantling battery was taken for alkali leaching,separated the active substances LiCoO2 and aluminum foil.After obtained the active LiCoO2 in waste lithium-ion battery,the acid leaching was carried out by sulfuric acid-bagasse system.The cobalt was leached from the waste lithium ion battery electrode material in order to study the effect of various reaction factors on cobalt leaching efficiency.The optimum conditions for acid leaching of sulfuric acid-bagasse system were obtained.The reaction mechanism of sugarcane bagasse improving the leaching effect was discussed.And then compared with the acid leaching effect of conventional system to explore the feasibility of acid leaching of sulfuric acid-bagasse system.Finally,cobalt in the leaching liquid were precipitated by ammonium oxalate solution.The effects of reaction factors on the recovery of cobalt were studied.The products were characterized by scanning electron microscopy,inductively coupled plasma emission spectroscopy and X-ray diffraction.The results indicates that:1.Separation experiment of lithium cobalt oxide active material and aluminum foil,compared with different conditions of separation effect,to determine the temperature at room temperature,NaOH solution concentration was 2.5mol/L,reaction time was 9h,without crushing.The optimum reaction conditions were as follows:the concentration of sulfuric acid solution was 2.54mol/L,the amount of sulfuric acid solution is 20mL,the reaction temperature was 80?,the ratio of liquid to solid was 199.20mL/g,the dosage of bagasse was 0.59g,the bagasse of the particle size of 0.50mm,metal Co leaching efficiency was 97.35%.The leaching effect of sulfuric acid-bagasse system is better than conventional acid leaching system.2.The bagasse as the reducing agent is involved in the leaching reaction.The aldehyde group in the bagasse and the intermediate RCOO.H2 can react with Co3+ to reduce it to Co2+,improve the leaching efficiency of cobalt.3.The optimum experimental conditions for the precipitation of cobalt oxalate were as follows:pH was 2,reaction temperature was 70?,reaction time was 60 min,[C2O42-]/[Co2+]ratio was 1.10.The results show that,the impurity of cobalt oxalate precipitate are few,the purity is high and the crystal form is good.In this paper,the sulfuric acid-bagasse system was used for the acid leaching of the electrode material,the recovery of cobalt was carried out by using ammonium oxalate as precipitating agent.At the same time it recovers lithium.And it realizes the secondary utilization of the bagasse.The recovery of cobalt in the cathode material from the used lithium-ion battery has certain application prospect.