The effectiveness of ion exchange resins in separating uranium and thorium from rare earth elements in acidic aqueous sulfate media. Part 2. Chelating resins
The effectiveness of ion exchange resins in separating uranium and thorium from rare earth elements in acidic aqueous sulfate media. Part 2. Chelating resins
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DOI：
10.1016/j.mineng.2018.04.017
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发表时间：
2018-07-01
影响因子：
4.8
通讯作者：
Nikoloski, Aleksandar N.
中科院分区：
文献类型：
--
作者：
Ang, Kwang Loon;Li, Dan;Nikoloski, Aleksandar N.
评价了不同官能团的螯合树脂在分离铀U（VI）和钍Th（IV）与稀土RE（III）中的潜在应用。候选树脂包括双-吡啶甲基胺树脂、氨基膦酸树脂、亚氨基二乙酸树脂和溶剂浸渍树脂。这些树脂对U（VI）和Th（IV）在选定的RE（III）的存在下，在不同浓度的硫酸介质中的吸附选择性进行了检查。结果表明，树脂的吸附性能与酸浓度有关。大多数候选树脂在0.1 mol/L H_2SO_4（或pH >= 1）或更低浓度下具有潜在的选择性吸附。根据它们的官能团，螯合树脂显示不同的选择性对U（VI），Th（IV）和RE（III）。结果表明，亚氨基二乙酸树脂对U（VI）和Th（IV）的亲和力高于RE（III）。在0.005mol/LH_2SO_4（或pH = 2）条件下，吸附剂对U（VI）和Th（IV）的吸附率约为90%，对RE（III）的吸附率小于20%。这可以通过考虑树脂的配位化学来解释，其中具有N-和O-供体原子的分子配体被证明强烈吸附U（VI）和Th（IV）。比较不同的O-供体基团（即，当树脂中的羧基为磺酰基、磷酰基和羧基时，树脂中的羧基对U（VI）、Th（IV）和RE（III）的分离效果最好。溶剂浸渍树脂的性能表明，利用空间效应，以获得高选择性的螯合树脂的U（VI）和Th（IV）超过RE（III）的可能性。此外，这些树脂的潜在应用集成过程中的顺序2级分离U（VI）和Th（IV）从RE（III）在硫酸介质中也提出。
Chelating resins with different functional groups were evaluated for their potential application in separating uranium U(VI) and thorium Th(IV) from rare earth elements, RE(III). The candidate resins included a bis-picolylamine resin, aminophosphonic resins, iminodiacetic resins, and solvent-impregnated resins. The adsorption selectivity of these resins towards U(VI) and Th(IV) in the presence of selected RE(III) was examined in sulfuric acid media of varying concentrations. It was evident that the adsorption performance of the resins was acid concentration-dependent. Most candidate resins had potentially feasible selective adsorption at or below 0.1 mol/L H2SO4 (or pH >= 1). Depending on their functional groups, the chelating resins displayed varying selectivity towards U(VI), Th(IV) and RE(III). It was found that the iminodiacetic resins exhibited the highest affinity for U(VI) and Th(IV) over RE(III). At 0.005 mol/L H2SO4 (or pH 2), the adsorptions of U(VI) and Th(IV) were approximately 90% while adsorption of RE(III) was less than 20%. This can be explained by considering the coordination chemistry of the resins whereby molecular ligands with N- and O-donor atoms were demonstrated to adsorb both U(VI) and Th(IV) strongly. Comparing the different O-donor groups (i.e., sulfonyl, phosphoryl and carboxyl), the carboxyl group from the iminodiacetic resin gave the best separation of U(VI) and Th(IV) from RE (III). The performance of the solvent-impregnated resins has indicated the possibility of exploiting steric effects to obtain a highly selective chelating resin for U(VI) and Th(IV) over RE(III). In addition, the potential application of these resins in an integrated process for sequential 2-stage separation of U(VI) and Th(IV) from RE(III) in sulfuric acid media is also presented.