The enrichment of 7Li by extraction with a Sudan I-Ionic liquid system

Lithium isotopes with high abundances (6Li and 7Li) are crucial for the advancement of nuclear energy. In order to achieve the effective separation of 7Li, a Sudan I-[HMIm][BF4]-anisole extraction system was built employing Sudan I (1-benzeneazo-2-naphthol) as the extractant and hydrophobic ionic liquid [HMIm][BF4] as the co-extractant. By optimizing the organic and aqueous phase components, the extraction rate of the system could reach up to 26.30%, and the single-stage separation factor of the system could reach 1.015 ± 0.001. Meanwhile, the mechanism of the extraction process was investigated, and it was found that the ratio of Sudan I to lithium ions is 1 : 1, and the thermodynamic enthalpy change of the extraction process was less than zero (ΔH < 0), indicating that the extraction process of the system was an exothermic process. The construction of the Sudan-ionic liquid extraction separation system provides a new idea for the study of 7Li enrichment and separation and also provides a possibility for the industrialization of high-abundance 7Li enrichment.