Leaching stability of simulated waste forms for immobilizing An super(3+) by Gd sub(2)Zr sub(2)O sub(7) with Nd super(3+)

• Published in: Journal of Wuhan University of Technology. Materials science edition 2014-10, Vol.29 (5), p.885-890
• Main Authors: Lu, Xirui, Chen, Mengjun, Dong, Faqin, Wang, Xiaoli, Wu, Yanlin, Xiao, Zhengxue
• Format: Article
• Language: English
• Subjects: Diffraction; Extraction; Neodymium; Phases; Pyrochlores; Sea water; Wastes; X-ray diffraction
• ISSN: 1000-2413; 1993-0437
• DOI: 10.1007/s11595-014-1014-4

In order to investigate the anti-leaching capability of pyrochlore Gd sub(2)Zr sub(2)O sub(7) immobilized An super(3+), trivalent neodymium was used as the simulacrums for radioactive wastes with trivalence, Gd sub(2-x)Nd sub(x) Zr sub(2)O sub(7)(0.0 x2.0) series samples were successfully synthesized by high temperature solid reaction and using Gd sub(2)O sub(3), ZrO sub(2) powders as starting materials. The experiments of long-term chemical stability were conducted in synthetic seawater at 40 and 70 degree C. The XRD diffractive data and extraction ratio of as-received samples were collected with the help of X-ray diffraction (XRD) instrument and inductively coupled plasma mass spectrometry (ICP-Mass). The results indicate that the phases of as-received compounds keep the single phase of pyrochlore. The extraction ratio of Gd super(3+), Zr super(4+) and Nd super(3+) in waste forms is increasing with the increase of immersion time in synthetic seawater. The extraction ratio of waste forms at 70 degree C is higher than at 40 degree C. The highest extraction ratio of Gd super(3+), Zr super(4+) and Nd super(3+) after 42 days is near 0.025 8, 0.003 8 and 0.045 2 mu g.mL super(-1), respectively.