废旧锂电池正极材料低温碳还原熟化过程动力学研究

Study on Kinetic of Recycling Cathode Material from Lithium-ion Batteries by Low Temperature Carbon Reduction and Acid Curing

采用低温碳还原硫酸熟化工艺处理废弃锂离子电池正极材料,综合回收有价金属Ni、Co、Mn。考察了熟化反应温度、熟化时间和硫酸用量对金属回收率的影响。结果表明,在反应温度250℃、反应时间30min、硫酸和正极黑粉的用量比为0.97mL/g时,有价金属的回收率均超过了96%。进一步对硫酸熟化过程中金属氧化物转变为金属硫酸盐的过程进行动力学研究,确认了废弃锂离子电池正极材料中有价金属硫酸熟化过程的动力学模型为收缩核模型,反应表观活化能在固膜扩散控制的范围内,浓硫酸低温熟化过程受内扩散控制。

Spent cathode materials in lithium-ion batteries were treated by low temperature carbon reduction and sulfuric acid curing to comprehensively recover valuable metals(Ni,Co,Mn).Effects of curing temperature,curing time,and dosage of sulfuric acid on recovery of valuable metals were investigated.The results show that recovery rate of valuable metals is 97%above under the conditions including reaction temperature of 250℃,reaction time of 30 min,and dosage ratio of sulfuric acid to cathode materials of 0.97 mL/g.Kinetics of metal oxides converting to metal sulfates during sulfuric acid curing are confirmed.The kinetic model of sulfuric acid curing process is shrinking core model and is controlled by internal diffusion,whose apparent activation energy is within range of solid film diffusion control model.