从盐湖卤水中萃取锂

选取磷酸三丁酯(TBP)为萃取剂,200号溶剂汽油为稀释剂,氯化铁(FeCl3.6H2O)为共萃取剂,从青海盐湖含锂卤水中萃取锂,并对TBP质量分数对萃取率的影响,相比对萃取率及分配比的影响进行研究。研究结果表明:共萃剂FeCl3在萃取过程中作用明显,同时,水相氢离子浓度是非常重要的影响因素,适当的酸度既可以保证锂离子进入有机相,减少氢离子与有机溶剂络合的机会,又可以保证铁离子在溶液中不发生水解;最佳萃取工艺条件如下:TBP质量分数为60%,萃取相比(O/A)为1.5,n(Fe3 )/n(Li )为1.3,水相氢离子浓度为0.05 mol/L。在此条件下,锂的萃取率可达到80%,锂、镁分离效果较好,萃取液经洗涤、反萃取和深度除镁后,可制备高纯度碳酸锂。

Extraction of lithium from bittern

With tri-butyl-phosphate(TBP) as extraction reagent,mineral spirit(200#) as dilution reagent and FeCl3.6H2O as co-extraction reagent,the extraction of lithium from Qinghai salt lake was studied.The effect of TBP concentration on extraction rate,and the effect of phase ratio on extraction rate and distribution ratio were analysed.The results show that the concentration of hydrogen ion in water phase is a very important factor,and a proper concentration of hydrogen ion not only ensures that lithium ion enters into organic phase and decreases the complexing of hydrogen ion and organic solvent,but also assures iron ion against hydrolyzing.The optimum parameters in the solvent extraction process are as follows: the phase ratio is 1.5,the molar ratio of Fe3 to Li is 1.3,TBP concentration is 60%,the concentration of hydrogen ion in water phase is 0.05 mol/L.Under the above conditions,the extraction rate of lithium can reach 80%,the separating effect of lithium with magnesium is good,and a high pure Li2CO3 can be made from the extracting solution after washing and demagnesium deeply.