隨著科技進步，電子、電器產品和電動車等科技產品的普及，永久磁鐵的運用越來越廣泛。而在永久磁鐵中，以釹鐵磁鐵和釤鈷磁鐵最具代表性，釹鐵磁鐵於1980年代發明，常用於馬達、硬碟和珠寶扣。釤鈷磁鐵則是發明於1970~1980年代，是最早發現的稀土磁鐵，因可適用在高溫和較大的磁場狀態中，常用於航天航空、渦輪機、國防軍工、微波器件、醫療設備等相關用品。
本研究目的為利用濕法冶金將釤鈷磁鐵切硝泥中的，釤、鈷、銅、鐵元素進行分離後，將可再利用的元素讓其回歸產線，並使用田口方法優化濕法冶金的製程。
依照實驗階段不同為兩個部分，第一部分浸漬的部分，利用田口方法優化硝酸浸漬釤鈷磁鐵切硝泥目的為提高浸漬效率，第二部分為元素分離，利用溶煤萃取、離子交換和選擇性沉澱等方式分離釤鈷磁鐵切硝泥中的釤、鈷、銅、鐵四種元素。
由田口方法中的L16表進行控制因子的選取和實驗，並得出最佳浸漬參數為在溫度30 °C 、固液比10 g/L、浸漬時間60分鐘、酸濃度2N，在該條件下浸漬率可以達到釤:98.7%、鈷:98.3%、銅:99.2%、鐵98.6%。
第二部分依照分離元素的不同，順序分別為銅離子分離、鐵離子分離、釤鈷離子分離。
銅離子分離步驟，根據Diniz等人研究[1]中可以知道在pH值小於1下，M4195的選擇比Cu(Ⅱ)>>Co(Π)>Fe(Ⅲ)>Sm(Ⅲ)，故使用M4195離子交換樹脂可以在不影響到其他離子濃度的狀況下分離銅離子，由實驗中可以觀察到pH值越高，可以增加同體積下的銅離子吸附量，可以得到在pH值為0.9，進料流速每小時2B.V.可以有效收集65B.V.之除銅溶液，可以吸附99.83%的銅離子。從實驗中觀察到脫附劑氨水度越高，越能有效富集銅離子，本研究以4M氨水進行脫附，可以脫附96.11%的銅離子。
鐵離子分離步驟，利用沉澱法將交換尾液中含有的釤、鈷、鐵離子中的鐵離子進行鹼沉澱[2]，使其轉變為氫氧化鐵，由實驗中可以發現在pH值3.5時，可以將99.6%的鐵離子沉澱。
釤鈷離子分離步驟，利用溶煤萃取法將上一步驟剩餘之釤、鈷溶液進行分離，使用使用二-2-乙基己基磷酸 (D2EHPA)進行萃取，由實驗可知在pH值3.5； D2EHPA濃度0.5(mol/L)；O/A比1時，能夠將釤離子99.9%分離至有機相，並根據佐貫須美子(1994)等人[3]利用草酸在作為反萃劑可以將釤離子反應為Sm2(C2O4)3沉澱分離出有機相，實驗後得到在草酸莫爾比為2時進行反萃取，可以有效地使釤離子沉澱而液相的鈷溶液利用沉澱法將鈷(II)溶液中使用草酸當作沉澱劑，可使鈷 (II)轉變為CoC2O4沉澱，而實驗後得到條件在pH值為3；溫度60 °C；莫爾比1.5的條件下可以將99.9%的鈷離子沉澱為CoC2O4。

This research aims to separate samarium, cobalt, copper, and iron in nitric acid solution and to recover higher-valued metals samarium and cobalt from magnet waste. Nitric acid was optimized with the Taguchi Method to improve the leaching ratio of samarium-cobalt magnet. The second part is the element separation of the four elements, namely samarium, cobalt, copper, and iron found in the magnet waste. First, M4195 resin was utilized to perform the ion exchange to obtain pure copper ions. Subsequently, the exchange tail fluid containing samarium, cobalt, and iron ions was subjected to alkali precipitation to convert iron ions to ferric hydroxide (Fe(OH)3). In the following extraction process, samarium ions were then separated into di-2-ethylhexylphosphoric acid (D2EHPA). Samarium were then precipitated in the form of Sm2(C2O4)3 using a stripping agent, oxalic acid. Interestingly, the same stripping agent could be used to precipitate cobalt (II) in the solution into CoC2O4 precipitates.

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