以酸性萃取劑萃取稀土元素鑭(III)和鈰(III)之平衡研究

The Extraction Equilibria of the Lanthanum(III) and Cerium(III) with Acidic Extractants

顏銘儒(Ming-Ru Yan)

指導教授 ： 蔡德華

國立臺北科技大學/工程學院/化學工程研究所/碩士(2014年)

https://doi.org/10.6841/NTUT.2014.00675

摘要

本論文是探討在25 °C下利用酸性萃取劑二(2-乙基己基)磷酸，以煤油為稀釋劑，分別探討萃取鑭和鈰單成分系統及鑭和鈰雙成分系統之萃取平衡實驗，將所得的萃取平衡數據，探討反萃取時所需氫氯酸濃度、pH值、萃取劑濃度等因素對萃取反應的影響。
由實驗數據可得，以酸性萃取劑D2EHPA萃取鑭和鈰單成分系統以及鑭和鈰雙成分系統平衡實驗中，鑭和鈰之萃取分配比會隨著萃取劑濃度及pH值增加而增加，並由圖解分析法可得有機錯合物組成。
在鑭的單成分系統中，所形成的有機錯合物為LaA3(HA)2和LaA3(HA)3。其萃取平衡常數為KLa32 = 0.0013 (kmol/m3)0.5和KLa33 = 0.029；在鈰的單成分系統中，所形成的有機錯合物為CeA3(HA)2和CeA3(HA)3。其萃取平衡常數為KCe32 = 0.0202 (kmol/m3)0.5和KCe33 = 0.075。
在鑭和鈰雙成分系統中，所形成的有機錯合物分別為LaA3(HA)2和LaA3(HA)3；CeA3(HA)2和CeA3(HA)3。其萃取平衡常數為KLa32 = 0.0023 (kmol/m3)0.5、KLa33 = 0.014和KCe32 = 0.0198 (kmol/m3)0.5、KCe33 = 0.033。其分離係數為：αCeLa = 3.0625[H2A2]-0.16。

關鍵字

萃取 ； 二(2-乙基己基)磷酸 ； 鑭(III) ； 鈰(III) ； 酸性萃取劑 ； 萃取平衡

並列摘要

In this study, the equilibrium of the separation of Lanthanum(III) and Cerium(III) by solvent extraction methods were investigated at 25°C；meanwhile, the acidic extractants D2EHPA was used. It began with the extraction equilibrium of Lanthanum(III) and Cerium(III) in extractants-kerosene solution and extractants-aqueous solution, and eventually the mixed Lanthanum(III) and Cerium(III) extractants-aqueous solution was studied.
The experimental results indicated that the extraction distribution ratio of Lanthanum(III) and Cerium(III) increased with either of rising concentrations of extractant in the organic phase or equilibrium pH values in the aqueous phase. Moreover we could realize the composition of the extractants through the graphical and numerical analysis.
The composition of LaCl3/D2EHPA complex formed in the organic phase were found to be LaA3(HA)2, LaA3(HA)3, and at the same time the respective corresponding equilibrium constants were KLa32 = 0.0013 (kmol/m3)0.5, KLa33 = 0.029 ; The composition of CeCl3/D2EHPA complex formed in the organic phase were found to be CeA3(HA)2, CeA3(HA)3, and furthermore the respective corresponding equilibrium constants were KCe32 = 0.0202 (kmol/m3)0.5, KCe33 = 0.075.
The composition of LaCl3, CeCl3/D2EHPA complex formed in the organic phase were found to be LaA3(HA)2, LaA3(HA)3；CeA3(HA)2, CeA3(HA)3, and simultaneously the respective corresponding equilibrium constants were KLa32 = 0.0023 (kmol/m3)0.5, KLa33 = 0.014；KCe32 = 0.0198 (kmol/m3)0.5, KCe33 = 0.033；separation factor：αCeLa = 3.0625[H2A2]-0.16

並列關鍵字

Extraction ； Di(2-ethylhexyl) phosphoric acid ； Lanthanum(III) ； Cerium(III) ； Acid extraction ； Extraction equilibrium

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