废旧磷酸铁锂脱锂后的铁磷渣锂吸附性能

Lithium Adsorption Properties of Ferro-phosphorus from Delithiated Spent Lithium Iron Phosphate

以磷酸铁锂正极粉脱锂后的铁磷渣为锂离子筛,高钠锂比的硫酸钠型卤水为原料,系统研究还原剂用量、锂浓度、锂钠比、吸附温度等对铁磷渣锂吸附性能的影响。结果表明,铁磷渣锂吸附性能随着还原剂用量、锂浓度、锂钠比和吸附温度的提高而提升;同时,锂钠选择系数与锂钠比呈正相关性,而与吸附温度呈负相关性。经过5次吸附-解吸附循环后,吸附和解吸附过程的溶损率分别低于0.15%和0.002%;同时,铁磷渣的吸附容量基本稳定在2.7mmol/g,Li/Na选择系数为3.88,表现出较佳的锂吸附性能和循环稳定性能。

Based on ferro-phosphorus obtained from delithiated spent lithium iron phosphate as lithium-ion sieve and high s Na/Li ratio of sodium sulfate brine as raw material,the effects of the amount of reducing agent,concentration of lithium,the ratio of lithium to sodium,and the temperature on the lithium adsorption performance of iron phosphorus slag were systematically investigated.The results show that the lithium adsorption capacity of ferro-phosphorus is improved with the increase of the dosage of reducing agent,concentration of lithium,the ratio of lithium to sodium,and the adsorption temperature.Besides,there is a positive correlation between selective coefficient of Li/Na and Na/Li ratio,while a negative correlation between selective coefficient of Li/Na and adsorption temperature.After five adsorption-desorption cycles,the dissolution rates of adsorption and desorption processes are lower than 0.15%and 0.002%,respectively.In addition,the lithium adsorption capacity of ferro-phosphorus remains as 2.7 mmol/g and the selective coefficient of Li/Na keeps at 3.88,indicating the excellent lithium adsorption performance and cycling performance.