Process For The Leaching Of Metal Values From Typical Spent Lithium Ion Batteries Using Organic Reductants

Change with our country emphasis on resources and evrionment protection,the legislative provisions had been gradually built.The regulation of waste lithium ion batteries belongs to solid waste.The improper management and handling will bring serious damage to the environment and humanbeing’s health.Therefore,Recycling of value metals from waste lithium ion batteries has multiple benefits,not only protecting the environment,but also recycled metals can bring economic benefits.Due to these double benefits from these ideas,this study aimed at collecting the mobile phone batteries and using waste lithium ion batteries as raw materials,dismantling batteries.Using hydrometallurgy method that the combination of sulfuric acid and biodegradable reductants applied in waste battery which containing cobalt and lithium value metals materials,research about the leaching efficiencies of lithium and cobalt optimal conditions.The research aim was to provide a more efficient and feasible solution for leaching process.（1）It was necessary to pretreat the waste lithium batteries before the metal leaching,and then analyzed the various substances obtained after pretreatment by means of characterizations.Herein a hydrometallurgical process was proposed to explore the possibility for the leaching of value metals from waste cathodic materials（LiCoO₂）of spent lithium ion batteries using organics as reductant in sulfuric acid medium.Using sulfuric acid as leaching reagent,cellulose,sucrose,glucose as reductants respectively,three different leaching systems were formed.The optimum parameters for leaching were obtained:concentration of sulfuric acid-3 mol/L,slurry density-25 g/L,reductive agent dosage-0.4 g/g,reaction time-120 min,reaction temperature-95 ^oC.Under the optimal leaching conditions,in sulfuric with cellulose system,the leaching efficiency of cobalt and lithium were 54%,and 100%respectively;In sulfuric acid with sucrose system,the leaching efficiency of cobalt and lithium were96%,and 100%respectively;In sulfuric acid with glucose system,the leaching efficiency of cobalt and lithium were 98%,and 96%respectively.Using different characterization methods,including UV–Vis,FT-IR,SEM and XRD,were employed for the tentative exploration of reductive leaching reactions using organic as reductants in sulfuric acid medium.All the leaching and characterization results confirm that both glucose and sucrose are effective reductants during leaching,while cellulose should be further degraded to organics with low molecular to achieve a satisfactory leaching performance.（2）According to the analysis of potentail-pH diagram of Li-Co-H₂O.With the decrease of pH,the LiCo O₂ were dissolved into the solution.Two approaches to leach LiCoO₂ can developed in theory:（1）Li CoO₂ were reduced directly to Co²⁺by decreasing potential and pH valuable of solution simultaneously and then transported into the solution.（2）LiCoO₂ were reduced to the intermediate product Co（OH）₂ by lowering solution’s potential,then Co（OH）₂ was transformed to Co²⁺by the decrease of the pH value and transported into the solution.It can be also concluded from reaction kinetics studies that the leaching of Co and Li were controlled by chemical reaction and internal diffusion respectively.In sulfuric acid with cellulose system,the apparent activation energies（Ea）for Co and Li are 48.5 kJ/mol and 10.6 kJ/mol respectively;In sulfuric acid with sucrose system,the apparent activation energies（Ea）for Co and Li are 36.2 kJ/mol and 16.8 kJ/mol respectively;In sulfuric acid with glucose system,the apparent activation energies（Ea）for Co and Li are 48.9k J/mol and 9.73 kJ/mol respectively.（3）In sulfuric acid with sucrose leaching system,the total annual cost of the calculated industry is 168.2 ten thousand yuan,and the total value of the total metal resource is 112.3 ten thousand yuan per year;In sulfuric acid with sucrose leaching system,the total annual cost of the calculated industry is 152.2 ten thousand yuan,and the total value of the total metal resource is 128.3 ten thousand yuan per year.