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研究了以HDEHP为萃取剂、DTPA为络合剂,在0.2—0.5mol/l HNO_3酸度下实现An~?(Ⅲ)、Ln~(2?)(Ⅲ)分离的工艺条件。结果表明,Am(Ⅲ)、Gd(Ⅲ)和En(Ⅲ)的分配比和HDEHP浓度的平方成正比,和酸度的3次方成反比。随温度的升高和料液中金属离子起始浓度的增大而降低。Am(Ⅲ)、Gd(Ⅲ)和En(Ⅲ)的萃取反应热依次为-7.1×10~3J·mol~(-1),-9.2×10~3J·mol~(-1)和-1.9×10~3J·nol~(-1)。采用1.0 mol/l HDEHP-煤油为萃取剂,pH3.2-3.6,0.15 mol/l DTPA-2 mol/l 乳酸为反萃剂,用模拟料液进行串级实验。Am(Ⅲ)近100%被回收,和Am(Ⅲ)共存于水相的Ln~(2?)(Ⅲ)少于3%。根据实验结果提出了概念流程。
The conditions for the separation of An ~ (Ⅲ) and Ln ~ (2?) (Ⅲ) with HDEHP as extractant and DTPA as complexing agent were studied under the acidity of 0.2-0.5mol / l HNO3. The results showed that the distribution ratio of Am (Ⅲ), Gd (Ⅲ) and En (Ⅲ) was proportional to the square of HDEHP concentration and inversely proportional to the third power of acidity. With the increase of temperature and the initial concentration of metal ions in the feed solution decreases. The extraction reaction heat of Am (Ⅲ), Gd (Ⅲ) and En (Ⅲ) were -7.1 × 10 ~ 3J · mol -1, -9.2 × 10 ~ 3J · mol -1 and -1.9 × 10 ~ 3J · nol ~ (-1). Using 1.0 mol / l HDEHP-kerosene as extractant, pH3.2-3.6,0.15 mol / l DTPA-2 mol / l lactic acid as stripping agent, cascade experiments were carried out with simulated feedstock. Nearly 100% of Am (Ⅲ) was recovered, and less than 3% of Ln ~ (2?) (Ⅲ) coexisted with Am (Ⅲ) in the aqueous phase. According to the experimental results, the concept of process is proposed.