Research On The Recovery Of Valuable Metals In Cathode Materials Of Waste Lithium Batteries

In recent years,the increasing market demand of lithium batteries leads to the increasing waste.In order to reduce the pollution caused by the spent lithium batteries and improve the utilization rate of the waste lithium batteries,the spent lithium batteries are usually recovered by hydrometallurgy,which can not only recover spent lithium batteries effectively,but bring some recovery benefits.In the process of hydrometallurgy,mainly rely on the leaching system composed of leactant and reductant to leaching the valuable metals in the cathode material of the waste lithium battery,and then the chemical precipition is used for recovery.Biomass has been gradually widely used in a variety of research due to their advantages of low cost and wide source.However,little research has been done in the field of waste lithium battery recycling.Research on the recovery of valuable metals in the cathode materials of spent lithium batteries.This paper took the spent Li Co O₂ battery and the spent Li Ni_xCo_yMn_zO₂ battery after factory test cycle failure as the research objects.Firstly,the spent Li Co O₂ battery was discharged and deactivated,and the collected fluid of the spent lithium battery was recovered with organic solvent to obtain the cathode materials for the research.The optimal recovery of the collected fluid of the spent lithium Li Co O₂ batteries and the spent Li Ni_xCo_yMn_zO₂ batteries was 98%and 97%,respectively.Then,the leaching system of citric acid-cornstalk was used to leaching the valuable metal in the cathode material of spent lithium batteries.The results showed that the leaching efficiency of Co and Li in the cathode materials of spent Li Co O₂ batteries were the optimal under the conditions of citric acid concentration of 2.5 mol/L,reductant mass fraction of 0.4%,solid-liquid ratio of 25 g/L,reaction temperature of 80?and reaction time of 150 min,were 84%and 98%,respectively.Under the conditions of citric acid concentration of 3.0 mol/L,reductant mass fraction of 0.5%,solid-liquid ratio of 30 g/L,reaction temperature of 80?and reaction time of 120 min,the leaching efficiency of Li,Ni,Co and Mn in the cathode materials of spent Li Ni_xCo_yMn_zO₂ were the optimal,were 98%,98%,88%and 90%,respectively.The cathode material of spent lithium batteries and cornstalk before and after leaching were tested by XRD and FT-IR.Finally,the valuable metals in the leaching solution were recovered by chemical precipitation.The optimal recovery of Co and Li were 93%and 95%,respectively,in the recovery of valuable metals from cathode materials of spent Li Co O₂ batteries.Ni,Co and Mn were recovered in form of co-precipition,the optimal recovery was 95%,and the optimal recovery of Li was 94%.The XRD was used to characterize the product recovered by chemical precipitation,the citric acid-cornstalk leaching system was economically analyzed.Taking 1 t spent Li Co O₂ batteries as an example,the cost of using citric acid-corn stalk leaching system was 13.5%lower than that of inorganic acid-hydrogen peroxide system,and brought considerable economic benefits.The use of cornstalk for the research of the recycling of spent lithium batteries has a relatively simple process and obvious treatment effects.This also provides new ideas for the effective utilization of cornstalks and realizes the recycling of biomass.