Solvent extraction is the key technical link for the preparation of nuclear-grade Hf and Zr for advanced nuclear reactors. In this study, the separation of Hf(IV) over Zr(IV) from the highly concentrated aqueous feed by solvent extraction with ionic liquid Aliquat 336 was investigated. The results indicated that thiocyanate forms of the ionic liquid dissolved in amyl acetate were more conducive to selective extraction of Hf(IV). Under the selected conditions, optimal extraction efficiency of Hf(IV) could be up to 94.5%. The separation factor of Hf(IV) to Zr(IV) was found to be 19.4. The extraction mechanism of Hf(IV) was revealed by slope analysis and FTIR analysis. The extracted complex of Hf(IV) was determined as [(A336⁺)₁₂(HfO²⁺)₃(H⁺)_(12x-2)(SCN⁻)_(16+12x)]. The extraction isotherm indicated that nuclear-grade Zr(IV) could be recovered from the raffinate via a two-stage extraction. The sulfuric acid solution showed appreciable selectivity in scrubbing of Zr(IV) from the loaded organic phase. The Hf(IV) species in the remaining loaded organic phase could be effectively stripped by 3.0 M (NH₄)₂CO₃ solution. Accordingly, a recyclable process flowsheet for the separation of Hf(IV) from Zr(IV) using Aliquat 336 was developed. It is believed that this process is a promising way for the preparation of enriched Hf and high purity Zr.

溶剂萃取是先进核反应堆制备核级Hf和Zr的关键技术环节。在这项研究中，研究了通过使用离子液体 Aliquat 336 进行溶剂萃取从高浓缩水性进料中分离 Hf(IV) 和 Zr(IV)。结果表明，溶解在乙酸戊酯中的离子液体的硫氰酸盐形式更有利于Hf(IV)的选择性萃取。在选定的条件下，Hf(IV)的最佳提取效率可达94.5%。发现 Hf(IV) 与 Zr(IV) 的分离因子为 19.4。通过斜率分析和FTIR分析揭示了Hf(IV)的提取机理。提取的 Hf(IV) 复合物确定为 [(A336 ⁺ ) ₁₂ (HfO ²⁺ ) ₃(H ⁺ ) _(12x-2) (SCN ^- ) _(16+12x) ]。萃取等温线表明核级 Zr(IV) 可以通过两阶段萃取从萃余液中回收。硫酸溶液在从负载有机相中洗涤 Zr(IV) 时显示出明显的选择性。剩余负载有机相中的 Hf(IV) 物质可被 3.0 M (NH ₄ ) ₂ CO ₃溶液有效汽提。因此，开发了使用 Aliquat 336 从 Zr(IV) 中分离 Hf(IV) 的可回收工艺流程。相信该工艺是制备富集 Hf 和高纯度 Zr 的一种很有前景的方法。