石油亚砜萃取U(Ⅵ)、Th(Ⅳ)的研究

SOLVENT EXTRACTION OF URANIUM(VI) ,THORIUM(IV) WITH PETROLEUM SULFOXIDES(PSO)

报道了石油亚砜(PSO)-煤油从硝酸介质中萃取铀(Ⅵ)、钍(Ⅳ)的实验结果。系统研究了硝酸浓度、PSO浓度、盐析剂浓度、铀(Ⅵ)浓度以及温度等对铀(Ⅵ)、钍(Ⅳ)萃取分配比的影响,发现PSO萃取规律与磷酸三丁酯(TBP)和二正辛基亚砜(DOSO)相类似。实验表明:当硝酸浓度在5—6mol/1间,D_v有一极大值,而D_(Th)极大值则出现在3—4mol/1之间。用斜率法测得铀(Ⅵ)、钍(Ⅳ)的溶剂化数为2和3。还计算了它们的萃取平衡常数和焓变。

The influence of the temperature, as well as the concentrations of nitric acid, petroleum sulfoxides (PSO),salting-out agent and metal ions on the distribution ratio of uranium(VI),thorium(IV) has been systematically studied. It is found that the extraction regularity of PSO is similar to that of DOSO and TBP. Both uranium (VI) and thorium (IV) exibit the maximum distribution ratios at 5-6 mol/1 HNO3 and 3-4 mol/1 HNO3,respectively. The extracted compounds are determined to be UO2(NO3)2·2PSO and Th(NO3·3PSO,respectively. The distribution ratios of uranium(VI) and thorium(IV) increase rapidly in the presence of salting-out agent. The extraction enthalpies of uranium (VI) and thorium (IV) with PSO are △HU = - 26 kJ/mol and △HTh =- 29 kJ/mol.