Abstract This study addressed the development of a continuous countercurrent extraction-scrubbing-stripping technique using a mixture of primary and tertiary amines as an effective extractant for both thorium (Th) and uranium (U) to simultaneously separate them from the leach solutions of xenotime concentrate from the Yen Phu mine (Vietnam). Systematic studies determined the optimum parameters of the separation, including the optimum concentrations of the mixture of the primary amine (N1923) and tertiary amine (tri-n-octyl amine), the optimum acidity (pH) of the feed liquor (Yen Phu xenotime leachate), the optimum contact time between phases for extraction, scrubbing and stripping processes, and the most suitable stripping reagent mixture. Using the optimum parameters, the optimum stage number and phase volumetric ratio for extraction, scrubbing, and stripping processes were calculated using the calculus method based on the law of matter conservation. The flow rates of both phases for extraction, scrubbing, and stripping were determined from the results of these studies and calculations. To optimize the separation of uranium and thorium from the Yen Phu xenotime leachate, counter-current simulations of extraction, scrubbing and stripping were done in a series of mixer-settler units. The results indicated that the selective separation of Th and U with almost no loss of rare earths (REs) and a minimal contamination of iron were obtained. The continuous countercurrent extraction-scrubbing-stripping technique shows potential applications in the commercial separation of Th and U from RE leachate after tests using a sequence of mixer-settler units on a pilot scale.

中文翻译：

---

使用伯胺和叔胺通过溶剂萃取从磷钇矿浸出液中分离钍和铀

摘要 本研究致力于开发一种连续逆流萃取-洗涤-汽提技术，使用伯胺和叔胺的混合物作为钍 (Th) 和铀 (U) 的有效萃取剂，同时将它们从磷钇矿的浸出液中分离出来。来自 Yen Phu 矿（越南）。系统研究确定了分离的最佳参数，包括伯胺 (N1923) 和叔胺 (三正辛胺) 混合物的最佳浓度、进料液 (Yen Phu xenotime) 的最佳酸度 (pH)浸出液）、萃取、洗涤和汽提过程各相之间的最佳接触时间，以及最合适的汽提试剂混合物。使用最佳参数、最佳阶段数和相体积比进行萃取、洗涤、根据物质守恒定律，使用微积分方法计算剥离过程。萃取、洗涤和汽提两相的流速由这些研究和计算的结果确定。为了优化从 Yen Phu 磷钇矿浸出液中分离铀和钍，在一系列混合沉降装置中进行了萃取、洗涤和汽提的逆流模拟。结果表明，获得了几乎没有稀土 (RE) 损失和铁污染最小的 Th 和 U 的选择性分离。连续逆流萃取-洗涤-汽提技术在使用一系列混合器-沉降器单元进行中试规模测试后，显示出从稀土浸出液中分离钍和铀的潜在应用。