Prevention of Interphase Crud Formation by Acetohydroxamic Acid

The method of elimination of crud formation by addition of acetohydroxamic acid(AHA) into the feed solution of simulated high-level liquid waste(HLLW) extracted by N,N,N′,N′-tetrabutyl-3-oxa-pentanediamide(TBOPDA)/OK was studied in the paper. The results of extraction experiments show that the distribution ratio of Zr(Ⅳ) sharply decreases as the increase with the concentration of AHA in the aqueous phase, while the distribution ratio of Pu(Ⅳ) remains high enough for its recovery. The stripping of Pu(Ⅳ), Zr(Ⅳ), and Am(Ⅲ) from the TBOPDA/OK phase were also studied. Zr(Ⅳ) can be effectively removed from the organic phase by a single stripping with a 0.2 mol/L AHA solution or a 0.01 mol/L HNO₃. Complete back -extraction of Pu(Ⅳ) was attained by three stages of cross-flow stripping with 0.05 mol/L AHA-0.1 mol/L HNO₃ or 0.2 mol/L AHA0.01 mol/L HNO₃. Am(Ⅲ) loaded in TBOPDA/OK is not effectively removed by dilute aqueous HNO_3^-AHA solution. The backextraction of Am(Ⅲ) by HNO₃-AHA solution can be greatly depressed by increasing HNO₃ concentration in the stripping solution.