錯合反應協同溶劑萃取高效分離廢鋰電池之有價金屬

科技及資訊傳輸的迅速發展，各式電子產品不斷推陳出新，二次鋰電池廢棄量也隨需求性、使用量及汰換速度增加而上升。目前國內回收的鋰電池皆採境外輸出處理，雖有工業研究機構開發鋰電池回收技術，但以往化學沉澱法應用在三元系鋰電池回收時，鈷、鎳、錳三金屬會共沉澱，導致回收金屬資源之純度與價值大減；傳統溶劑萃取法則仍存在萃取級數過高之問題。本研究主要探討三元系廢鋰電池中有價金屬之萃取分離技術，以D2EHPA預先萃取錳之最佳參數條件為：萃取劑D2EHPA與稀釋劑煤油體積比為1:4，油水體積比為1:1，經三級萃取，皂化率分別為60%、20%、20%，錳的萃取率可達90.99%，而鈷、鎳、鋰的總損失率分別僅6.37%及6.47%、6.76%。再以含SCN-離子的NH4SCN為錯合劑將溶液中Co(II)、Ni(II)反應為錯合物Co(SCN)42-、Ni(SCN)42-再進行萃取，錯合反應協同溶劑萃取之最佳參數條件為：萃取劑HEHEHP與稀釋劑庚烷體積比為1:4，皂化率為60%，油水體積比為1:1，萃取劑HEHEHP相對錯合劑NH4SCN莫耳數比為1:1，鈷單級萃取率可達97.55%，鎳的萃取率僅5.75%，分離係數可達379，為傳統溶劑萃取的5倍。

關鍵字

廢鋰電池；溶劑萃取；錯合反應；鈷；錳；鎳

並列摘要

With the rapid development of technology and information transmission, various electronic products are constantly being introduced, and the amount of secondary lithium batteries is also increasing with increase in demand, usage and replacement rates. At present, lithium batteries recovered in Taiwan are processed outside the country. Although industrial research institutes have developed lithium battery recycling techniques, cobalt, nickel and manganese metals co-precipitated in previous chemical precipitation methods applied to the recovery of ternary lithium batteries. Hence, the purity and value of recycled metal resources were reduced greatly. Also, the traditional solvent extraction method still faces the problem of excessive extraction levels. This study mainly explores the extraction and separation technique of valuable metals in ternary waste lithium batteries. The optimal parameters for pre-extracting manganese with D2EHPA are: (1) the volume ratio of D2EHPA extractant to kerosene diluent is 1:4, and (2) the volume ratio of oil to water is 1:1. After three-stage extraction, the saponification rates are 60%, 20%, 20%, and the extraction rate of manganese is up to 90.99%, while the total loss rates of cobalt, nickel and lithium are only 6.37% and 6.47% and 6.76% respectively. Next, Co(II) and Ni(II) in the solution are reacted with SCN- ion-containing NH4SCN complexing agent to form the complexes Co(SCN)42- and Ni(SCN)42-. The complexing reaction is combined with solvent extraction with the optimum parameters as follows: (1) The volume ratio of extractant HEHEHP to diluent heptane is 1:4; (2) the saponification rate is 60%; (3) the oil-water volume ratio is 1:1, and (4) the molar ratio of HEHEHP extractant relative to the NH4SCN agent is 1:1. The single extraction rate of cobalt is up to 97.55%, while the extraction rate of nickel is only 5.75%. Also, the separation coefficient is up to 379, which is 5 times that of traditional solvent extraction.