High Efficiency-short Process Of Waste Lithium Iron Phosphate Study On The Recovery Of Lithium Dihydrogen Phosphate

With the rapid development of the field of new energy vehicles,the use of lithium iron phosphate batteries is increasing day by day,leading to its increasing amount of end-of-life.A reasonable recycling process is necessary to achieve comprehensive utilization of resources and environmental protection.At present,most of the recycling technologies for used lithium iron phosphate batteries have long recycling processes,complex operations and high energy consumption,and there is an urgent need for a highly efficient,short process and low energy consumption method for resource recovery of used lithium iron phosphate batteries.To this end,this thesis proposes a high-efficiency-short-process-low-consumption technology process to achieve large-scale recycling of lithium iron phosphate batteries and obtain high value-added products,so as to further promote the green and efficient recycling process of used lithium iron phosphate batteries.The main conclusions are as follows.（1）The results of waste lithium iron phosphate batteries after crushing and sieving show that the material<0.300 mm accounts for 63.346%,the main component of this part of the material is Li Fe PO₄ and a small amount of copper and aluminum foil,74.94%of the lithium enrichment in the battery at this particle level,therefore,the material<0.300 mm is selected for phosphoric acid-hydrogen peroxide system leaching,and then purified and de-mixed lithium enrichment solution Recovery of valuable metal Li.（2）The results of organic extraction and hydrolytic precipitation experiments on the purification and de-hybridization of lithium enrichment solution showed that the effect of using hydrolysis for de-hybridization was better.The best purification and de-hybridization conditions were p H=6,T=20°C,and 0.1 g/m L of Li OH for 30 min.The removal rates of impurities Al,Fe and Cu were 100%,100%and 82.61%,respectively,and the loss rate of Li was 53.541%.The purification solution was evaporated and concentrated to produce lithium dihydrogen phosphate powder,which has a regular flake structure and can be subsequently tried to be used in the manufacture of lithium iron phosphate for lithium-ion battery materials.（3）Lithium dihydrogen phosphate was produced from waste lithium iron phosphate batteries by the leaching-Li OH hydrolysis and decontamination-evaporation and concentration process with H₃PO₄-H₂O₂ system,which is a short process with low energy consumption and provides technical guidance for green and efficient recycling of waste lithium iron phosphate batteries.