Recovery Of Metal From Spent Lithium-ion Batteries

Disposal of spent lithium-ion batteries(LIBs) have becoming more and more important with the growth of production and use of LIBs. Recycling treatment has attracted more and more attentions. Compared to other methods of treatment, recycling can not only resolves environmental problem, but also slows the lack of resource effectively by recovering and reusing of valued metals from LIBs.In exploration experiment foundation, in view of waste lithium-ion batteries composition characteristic and combining actual situation, the technical process of recycling the valuable metal aluminum, copper, cobalt, lithium etc. from spent lithium-ion batteries is as follows:Battery discharge processing→machinery broken→separation anode and cathode→separation cobalt from aluminum→solution leaching with vitriol and hydrogen peroxide→precipitation and separation cobalt and lithium. This technological design simple, focuses to the practical application, has realized the resources recycling use, the non-waste production, is friendly to the environment. The concrete research contents and obtained achievements are as follows:Through pretreatment, machinery broken monomer battery, divided the battery anode and cathode, the positive electrode material in 450℃roasted 2h, excepted cementing agent PVDF, supersonic vibrated 2min, succeeded separation LiCoO2 from the aluminum foil, recycled aluminum. The cathode material in 200℃roasted 2h, supersonic vibrated 1min, recycled copper. Under 400℃,600℃,800℃temperatures carried on the heat treatment to LiCoO2, through XRD and SEM analysis discovery:Along with the roasting temperature increase, the Co3O4 content gradually increases, LiCoO2 pellet tiny and uniformity, dispersivity good, is easy to leach.With the sulfuric acid-hydrogen peroxide solution system leaching to positive electrode active material LiCoO2, successful separation acetylene black impurity. Carried on the chiasma experiment in the single factor experiment foundation, finally discovered:The cobalt and the lithium leaching rate advanced with the reaction temperature and time growth, the sulfuric acid density and the quantity of the hydrogen peroxide increase. The determination best leaching condition is:The temperature is 80℃, time is 120min, the acid:oxygen is 4:1, sulfuric acid density is 4mol/L, the cobalt and the lithium leaching rate achieved 94.3%.This article also has researched the leaching reaction kinetics of LiCoO2, obtained the following conclusion by the experiment:(1)According to the formula lntc=-mlnc+I, figured out the reaction order of sulfuric acid(m) is 0.82. Therefore between the cobalt leaching response speed and the acid concentration relations may be represented as: Explained it is bigger influence the sulfuric acid density to the cobalt leaching rate,Response dynamic equation is lntc=-0.82 lncH++3.6812.(2) According to the formula figured out the apparent activation energy(E) is 17.3kJ/mol, this value indicated, cobalt leaching response control step is the diffusing step.Carried on the precipitation separation experiment to the cobalt and lithium, wound compared with the direct synthesis and the process legitimately to sink the cobalt effect, separately precipitated alpha-Co(OH)2 and beta-Co(OH)2, and burnt 4h in 800℃, manufactured Co3O4. Sinked the lithium with saturated Na2CO3, manufactured Li2CO3. Through XRD analysis discovery, the Co3O4 and Li2CO3 product diffraction peak is incisive, the purity is higher.The entire experiment designs simply, efficiency high, the recycling is thorough, has the better application prospect.