| There have been lots of researches and summaries on the global cobalt and lithium resources, market and its application in Li-ion battery, cobalt and lithium resources recycling etc. Li-ion battery is important application of nonferrous metal lithum and colbt, at the same time, also become important twice resource of lithum and colbt. Therefore, the technology and its scientific foundation on materialization metallurgy of LiCoO2 film covered on aluminum foil have been studied in this paper.The LiCoO2 covered on aluminum foil can be separated from Al-foil by heat treatment. PVDF is decomposed from 381.8℃to 449.5℃. In the temperature above 500℃, the reaction of aluminum foil in the positive electrode flat are to be made strongly with oxygen, thus strong heat emitted in oxidization reaction led to materials on fire. PVDF in positive electrode flat has decomposed completely by the heat treatment of 2 hours in 450℃. After binder PVDF is decomposed the materials containing LiCoO2 and covering on Al foil can be peeled off from the base material of aluminum foil. In the course of heat treatment the original layer structure of LiCoO2 have been partially destroyed by the HF that is produced in PVDF decomposition and react with LiCoO2. The Li/Co mole ratio of the LiCoO2 powers after the heating is lower than 1.00. At the same time, LiCoO2 pellet surface becomes relatively rough with obvious slight crackles occurred.The dissolution of LiCoO2 is related closely with its stability in aqueous solution. The potential-pH figure of Li-Co-H2O system has been drawn and the solubility of LiCoO2 in aqueous solution have been analysed. LiCoO2 can exist steadily in aqueous solution. The thermodynamic advantage district of LiCoO2 is adjacent with thermodynamic advantage districts of Co(OH)3, Co2+ and Co(OH)2. LiCoO2 can be dissolved in aqueous solution by 3 ways with the LiCoO2 dissolved into Co2+ and Li+ by acids through intermediate outcome Co(OH)3 firstly, and that directly dissolved by acids secondly, and finally with that dissolved by reducing agent and through intermediate outcome Co(OH)2. The acid dissolution with the role of reducing agent is the most effective way. The process of LiCoO2 dissolved in mix solvent of H2O2+ H2SO4 has studied by this test. The reaction speed of dissolution of LiCoO2 for concentration of H2O2 and H2SO4 is an apparent reaction order. The apparent activation energy of the process is 14.9 KJ·mol-1. The controlling step of the process is a diffusion of reactants to interface of solid and liquid. The suitable process conditions are that the concentration of H2SO4 is 2.0～2.5 mol·L-1, the concentration of H2O2 is 1.1～1.2 mol·L-1, reaction temperature is larger than 80℃, stirring and reaction time is 120 min. Under these conditions LiCoO2 dissolution rate can be larger than 99%.The hydrolysis behavior of aluminum in strong electrolyte sulphate solution is the foundation of separation aluminum from lithium and cobalt sulphate solution. In aqueous solution strong electrolysis sulfate have buffering effect to the acid in solution due to the hydrolysis of SO42-, and has important influence on the hydrolysis of aluminum. According to synthesizing balanced principle in solution reaction and reasonable system design, aluminum hydrolysis is studied by mathematics simulated analysis firstly. Al3+, AlOH2+, Al(OH)4-, Al2(OH)24+, Al6(OH)153+ and Ali3(OH)327+ are the major existent bodies of aluminum ion hydrolysis in solution. When pH is higher (larger than 9) Al(OH)3 is formed in aluminum hydrolysis. Hydrolysis tests of alkali titration to aluminum in solution are made. Two platforms in the curve of titration occur when COH/CAl is from 0 to 3.5, and respectively show hydrolysis-polymerization and hydrolysis-precipitation of aluminum in solution. Hydrolysis-precipitation goes on obviously when COH/CAl is larger than 2.2, and finishes when COH/CAl is at 3.5. Higher temperature is helpful to the hydrolysis-precipitation of aluminum in solution. The light hydrolysis of cobalt can strengthen the hydrolysis-precipitation of aluminum in cobalt sulfate solution. In lower pH cobalt salt hydrolyzes and Co(OH)2 sediment pellets are produced. These pellets adhere to, are swept and entrapped by aluminum-polymers that are produced in the hydrolysis course and have positive charge and plane reticular structure. Therefore, the aluminum-polymers can precipitate together with Co(OH)2 sediment pellets in lower pH. The solid-phase transformation based on anion CO32- put frist forward for separating cobalt in lithium and cobalt sulfate solution is based on the chemical equilibriums of CO2-H2O system. Solid Li2CO3 is used to be as precipitation and low CO32- environment is made with solid Li2CO3 suspension solution. CoCO3 is made from cobalt and lithium mix sulfate solution with replacing Li+ in solid Li2CO3 by Co2+ in solution.The process of solid phase transformation on the basis of anion CO32- has been confirmed by the experiments, and a series of test results has been gotten. The quality of Li2CO3 that react with Co2+is nearly equal to chemical reaction measure for complete precipitation of cobalt in solution. A little excessive Li2CO3 (chemical reaction measure rate times is 1.05～1.10) is suitable for the process of solid phase transformation. By the way of reducing Co2+ concentration in solution and increasing reaction temperature, reaction time and maturation time etc. the size of reaction outcome CoCO3 can be increased. In the condition of higher temperature, lower pH value and less joining speed of cobalt salt solution, complete crystallization and dense CoCO3 sediment can be made. The comprehensive test of the reactor scale of 20 L is made and suitable conditions are obtained. The suitable test conditions are that temperature is 50℃, ratio of liquid to solid is 4:1, concentration of Co2+ in sulfate solution (Co/Li=1) is 1.50 mol·L-1 and pH value of the solution is 4.0, chemical reaction measure rate times of Li2CO3 is 1.1, feeding and reaction time is 90 min and maturation time is 60 min. In the suitable test conditions, precipitation ratio of Co2+ is 99.76%, central size of the CoCO3 particle is 8.26μm and particle size distribution is good.The Li+,Na+//SO42-,CO32--H2O interactive equilibrium is the theoretical foundation of the process of reaction crystallization Li2CO3 in lithium sulfate solution. The reaction equilibrium law is used to research partial crystallization process of Li+,Na+//SO42-,CO32--H2O interactive equilibrium related to the responsive crystallizing process of Li2CO3. When steady Li2CO3-Na2SO4 salt-pair is balanced for reaction crystallization, the average activity coefficients of Li2CO3 and Na2SO4 in solution are in agreement with the improved typical electrolyte solution model. The dissolution equilibriums of Na2SO4 and Li2CO3 in interactive system of Li+,Na+//SO42-,CO32--H2O accords with following mathematic relation.The tested data analysis of the crystallization equilibrium of steady Li2CO3-Na2SO4 salt-pair in Li+,Na+/SO42-,CO32--H2O interactive system shows that high crystallization ratio of Li2CO3, low liquid-solid ratio and relatively high comprehensive reaction transformation ratio could be got when reactant measure ratio (Na2CO3/Li2SO4) is 1.0.The crystallization Li2CO3 process in lithium sulfate solution has been done by experiments with the research results showing that with solid reactant (sodium carbonate), Li crystallization rate increases with the increase of initial Li salt concentration, reactant measure ratio (Na2CO3/Li2SO4), reaction temperature and reaction time. The better crystallization conditions are that initial Li+ concentration is 20g·L-1, the chemical reaction measure of reactants is equal (Na2CO3/Li2SO4 is 1.0), reaction temperature is normal, reaction and feeding time is 60 minutes and stirring and mature time is 30 minutes. Orthogonality test results show that the influence order from big to little of the influencing factor is:initial concentration of lithium in solution, sodium carbonate quantity used in crystallization course, reaction time, and reaction temperature. Under the optimization condition of Li2CO3 reaction crystallization, Li receipt rate is larger than 82%. The analysis of XRD, SEM and TG/TDA shows that structure of Li2CO3 crystallization is complete and in order, the form of Li2CO3 pellets dehydrated is flat, size of pellets is more even, the melting point of Li2CO3 is 723.1℃, decomposition of Li2CO3 occur in more than melting point temperature under the optimization condition of crystallization.The method by that the nanometer Co3O4 is prepared with completely dry and automatic purification is suggested for the first time. Based on solid-state reaction at low temperature and hot sublimation of NH4C1, CoCl2·6H2O and (NH4)2C2O4·H2O are used as raw materials, and the mixture of CoC2O4·2H2O and NH4Cl is prepared through solid-state reaction at low temperature. The mixture is handled at the temperature above sublimating temperature of NH4Cl, NH4C1 is sublimated, CoC2O4·2H2O is decomposed, and pure nanometer Co3O4 is prepared. Grinding and using reactant containing crystallization water can promote the solid-state reaction at lower temperature, properly excessive (NH4)2C2O4·H2O can guarantee the complete transformation of CoCl2·6H2O, the sublimation of NH4Cl can reduce reunite of outcome particles. Nanometer Co3O4 prepared is in good scattering and with complete crystal shape by joining suitable quantity scatter dose, adapting suitable dry temperature and heat-decomposing temperature of forerunner mixture. Synthesizing test results, the better conditions of solid-state reaction at low temperature in which nanometer Co3O4 is prepared are that ratio of CoCl2·6H2O and (NH4)2C2O4·H2O is 1:1.2, suitable quantity (the 2% of reactants amount) assemble glycol is added, grinding and reaction time is 30 minutes, outcome mixture is dried in 120℃for 10 hours, and dried mixture is burn in 350℃for 3 hours. Under these technology conditions, the synthesized nanometer Co3O4 has a particle size of 8nm with symmetrical distribution.
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