酸浸—萃取—沉淀法回收废锂离子电池中的钴

Recover of cobalt from spent lithium ion batteries by acid leaching-extraction-precipitation process

采用酸浸—萃取—沉淀法回收废锂离子电池中的钴。实验结果表明:废锂离子电池在600℃下煅烧5 h可将正极材料上的有机黏结剂与正极活性物质分离;正极活性物质在Na OH溶液浓度为2.0 mol/L、n(Na OH)∶n(铝)=2.5、碱浸温度为20℃的条件下碱浸反应1 h后,铝浸出率达99.7%;已除铝的正极活性物质在硫酸浓度为2.5 mol/L、H_2O_2质量浓度为7.25 g/L、液固比为10、酸浸温度为85℃的条件下酸浸反应120 min,钴浸出率高达98.0%;酸浸液在p H为3.5、萃取剂P507与Cyanex272体积比为1∶1的条件下,经2级萃取,钴萃取率为95.5%;采用H_2SO_4溶液反萃后在硫化钠质量浓度为8 g/L、反萃液p H为4的条件下沉淀反应10 min,钴沉淀率达99.9%。

Cobalt was recovered from spent lithium ion batteries by acid leaching-extraction-precipitation process. The experimental results show that： Organic binders on cathode material of spent lithium ion batteries can be separated from positive active materials （PAMs） by calcinations at 600 ℃ for 5 h; When PAMs is treated under the conditions of NaOH concentration 2.0 mol/L, n （NaOH） ： n （A1）=2.5, alkaline leaching temperature 20 ℃ and alkaline leaching time 1 h, the leaching rate of aluminum is 99.7%; Under the conditions of H2SO4 concentration 2.5 mol/L, H202 mass concentration 7.25 g/L liquid-solid ratio 10, acid leaching temperature 85 ℃ and acid leaching time 120 min, the leaching rate of cobalt is 98.0%; When the acid leaching solution is extracted twice under the conditions of pH 3.5 and volume ratio of extracting agent P507 to Cyanex272 is 1 ： 1, the cobalt extraction rate is 95.5%; The extracted liquid is back-extracted with H2SO4 solution and then reacted with sodium sulfide under the conditions of sodium sulfide mass concentration 8 g/L, water phase pH 4 and precipitation time 10 min, the precipitation rate of cobalt is 99.9%.