A solvent composition and corresponding method for extracting cesium (Cs) from aqueous neutral and alkaline solutions containing Cs and perhaps other competing metal ions is described. The method entails contacting an aqueous Cs-containing solution with a solvent consisting of a specific class of lipophilic calix[4]arene-crown ether extractants dissolved in a hydrocarbon-based diluent containing a specific class of alkyl-aromatic ether alcohols as modifiers. The cesium values are subsequently recovered from the extractant, and the solvent subsequently recycled, by contacting the Cs-containing organic solution with an aqueous stripping solution. This combined extraction and stripping method is especially useful as a process for removal of the radionuclide cesium-137 from highly alkaline waste solutions which are also very concentrated in sodium and potassium. No pre-treatment of the waste solution is necessary, and the cesium can be recovered using a safe and inexpensive stripping process using water, dilute (millimolar) acid solutions, or dilute (millimolar) salt solutions. An important application for this invention would be treatment of alkaline nuclear tank wastes. Alternatively, the invention could be applied to decontamination of acidic reprocessing wastes containing cesium-137.
本发明描述了一种从含有
铯(Cs)和其他竞争性
金属离子的中性和碱性
水溶液中提取
铯(Cs)的溶剂组合物及相应方法。该方法涉及将含
铯(Cs)的
水溶液与由特定类脂溶性杯[4]
芳烃冠醚萃取剂和含有特定类烷基-芳香
醚醇的烃基稀释剂组成的溶剂接触。随后,从萃取剂中回收
铯(Cs)价值,并通过将含Cs的有机溶液与
水剥离溶液接触,随后回收溶剂,来进行
铯的提取和剥离。这种联合提取和剥离方法在高度碱性废液中去除放射性核素
铯-137的过程中特别有用,该废液中
钠和
钾的浓度也非常高。无需对废液进行预处理,可以使用安全且廉价的剥离过程使用
水、稀酸溶液或稀盐溶液回收
铯(Cs)。该发明的一个重要应用是处理碱性核废槽底。或者,该发明可应用于含
铯-137的酸性再处理废液的去污。