Cesium is an important strategic resource, and solvent extraction is the most frequently used technology for its extraction from various minerals and brines. However, this common method faces operational and cost problems owing to large alkali consumption. A synergistic extraction system consisting of 4--butyl-2-(α-methylbenzyl) phenol (t-BAMBP) and di-(2-ethylhexyl) phosphoric acid (D2EHPA) was designed and used to extract Cs from an alkali-free solution. The effects of variables such as: (i) pH, (ii) concentration of t-BAMBP and D2EHPA, (iii) temperature, (iv) Cs concentration, and (v) coexisting cations, on the Cs extraction performance of the synergistic system were investigated. The most suitable organic phase composition was 1.0 mol/L t-BAMBP and 0.1 mol/L D2EHPA in kerosene, and the synergistic coefficient was up to 57 at 25 °C and an organic/aqueous phase volume ratio of 1/1. The extraction sequence of cations using the t-BAMBP–D2EHPA synergistic system followed the descending order Cs > Rb > Ca > K > Li > Mg > Na. The chemical formula of the extracted species was determined as [CsA(HA)(ROH)] using the slope method. The Cs extraction process is an exothermic reaction with an enthalpy () of −55.3 kJ mol, confirmed by the thermodynamic study. After three-stage countercurrent extraction, the extraction efficiency of Cs was 92.6%, demonstrating excellent selectivity from coexisting cations. The t-BAMBP–D2EHPA synergistic system showed outstanding economic and environmental advantages and a good application prospect to develop a conceptual process flowsheet for extraction with this system and stripping with HCl to separate cesium salt from salt-lake brine.

中文翻译：

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使用 4-叔丁基-2-(α-甲基苄基)苯酚-二-(2-乙基己基)磷酸协同系统从无碱溶液中提取铯：从盐湖卤水中分离铯盐的概念工艺流程图


铯是一种重要的战略资源，溶剂萃取是从各种矿物和卤水中提取铯的最常用技术。然而，由于碱消耗量大，这种常用方法面临操作和成本问题。设计了一种由4-丁基-2-(α-甲基苄基)苯酚(t-BAMBP)和二(2-乙基己基)磷酸(D2EHPA)组成的协同萃取体系，用于从无碱溶液中萃取Cs 。 (i) pH、(ii) t-BAMBP 和 D2EHPA 浓度、(iii) 温度、(iv) Cs 浓度和 (v) 共存阳离子等变量对协同系统的 Cs 提取性能的影响被调查。最合适的有机相组成为煤油中的1.0 mol/L t-BAMBP和0.1 mol/L D2EHPA，在25 ℃、有机相/水相体积比为1/1时，协同系数高达57。使用t-BAMBP-D2EHPA协同系统提取阳离子的顺序为Cs>Rb>Ca>K>Li>Mg>Na。使用斜率法确定提取物质的化学式为[CsA(HA)(ROH)]。热力学研究证实，Cs 提取过程是一个放热反应，其焓 () 为 -55.3 kJ mol。经过三级逆流萃取后，Cs的萃取效率为92.6%，表现出对共存阳离子的优异选择性。 t-BAMBP-D2EHPA协同系统显示出突出的经济和环境优势以及良好的应用前景，开发了用该系统萃取并用HCl反萃取从盐湖卤水中分离铯盐的概念工艺流程。