The interaction of Np(V), Pu(VI) and Tc(VII) with metal in alkaline solutions

• Published in: Journal of alloys and compounds 1998-06, Vol.271, p.803-808
• Main Authors: Silin, V.I, Kareta, A.V
• Format: Article
• Language: English
• Subjects: Experimental results; Neptunium; Plutonium; Reductive sorption on metal; Technetium
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/S0925-8388(98)00212-6

The interaction of Np(V), Pu(VI) and Tc(VII) with metal reductants Zn, Cr, Sn and their alloys was investigated in 0.5–4 mol l −1 NaOH solutions in static and dynamic conditions (by filtration of solutions through the column filled with grains of metal). In this paper, it was found that the reduction and succeeding precipitation hydroxides of these elements, on the surface of metal grains from 0.5 to 4 mol l −1 NaOH solutions, gives a decontamination factor (DF) from 1.1 to 67. The best result was achieved for Pu (DF=67) on Cr grains after 2.5 h contact at 60°C with 0.5 mol l −1 NaOH solution containing Pu(VI). Increasing the NaOH concentration, and the addition of chromate ions and complex-forming agents to alkaline solution results in a decrease of the decontamination factor (DF). A better result for Np sorption from 1 mol l −1 NaOH solutions was achieved after longer contact, than for Pu, with Cr and Zn grains. The maximum DF=8.9 was achieved for Tc on a column with Zn grains after filtration with a 3.5 mol l −1 NaOH solution containing Tc(VII). Washing out of Np and Pu, sorbed on the Cr grain surfaces, was achieved using an acid solution (1 mol l −1 HNO 3). The technetium was desorbed from metal surface by 10% H 2O 2 solution.