Me-TODGA萃取模拟高放废液中的An(Ⅲ)与Ln(Ⅲ)

    Extraction of An(Ⅲ) and Ln(Ⅲ) From Simulated High Level Liquid Waste by Me-TODGA

    • 摘要: N,N,N',N'-四辛基-3-氧戊二酰胺(TODGA)是目前研究最多的酰胺荚醚类萃取剂,但其萃取An(Ⅲ)与Ln(Ⅲ)的能力强,导致反萃困难。为此,设计了以N,N,N',N'-四辛基-2-甲基-3-氧戊二酰胺(Me-TODGA)为萃取剂的酰胺荚醚流程,并采用模拟高放废液(SHLLW)对该流程进行验证。结果表明:经过6级萃取和10级洗涤,SHLLW中三、四价金属离子的萃取率均大于99.5%;采用0.3 mol/L HNO3经过16级反萃,An(Ⅲ)与Ln(Ⅲ)的反萃率在95%以上,Zr4+的反萃率为68.0%,其它金属离子的浓度均低于初始浓度的2.1%。该流程实现了较高酸度(0.3 mol/L HNO3)条件下An(Ⅲ)与Ln(Ⅲ)的反萃,减少了界面污物的产生,为酰胺荚醚流程的设计及应用提供了基础数据。

       

      Abstract: N,N,N',N'-tetraoctyl-3-oxapentanediamide(TODGA) is the most studied extractant among diglycolamides, but its extraction ability for An(Ⅲ) and Ln(Ⅲ) is too strong, making the stripping of An(Ⅲ) and Ln(Ⅲ) is difficult. In this paper, a novel diglycolamides process employing N,N,N',N'-tetraoctyl-2-methyl-3-oxapentanediamide(Me-TODGA) was designed as the extractant. The process was verified using simulated high level liquid waste(SHLLW). The results show that the extraction rate of trivalent and tetravalent metal ions exceeds 99.5% after 6-stage extraction and 10-stage scrubbing. After 16-stage stripping with 0.3 mol/L nitric acid, the stripping rates of An(Ⅲ) and Ln(Ⅲ) are over 95%, the stripping rate of Zr4+ is 68.0%, and the concentrations of other metal ions are all lower than 2.1% of the initial concentration. This process enables efficient stripping of An(Ⅲ) and Ln(Ⅲ) under higher acidity (0.3 mol/L nitric acid), which reduces the generation of interfacial crud, and provides basic data for the design and application of the diglycolamides process.

       

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