Vitusite glass-ceramics wasteforms for immobilization of lanthanide wastes generated by pyro-processing

Abstract

Glass-ceramic wastefonns containing vitusite (Na3Ce(PO4)(2)) and Ce-rich crystals were investigated to immobilize lanthanide oxide wastes generated by pyro-processing. Controlled crystallization of alkali borosilicate glasses containing small amounts of P2O5 by heating at T > 600 degrees C for 3 h resulted in formation of vitusite as a major crystalline phase with a minor Ce-rich crystalline phase. Lanthanide oxide waste loading was 11.87 wt%. Rare-earth wastes were efficiently immobilized inside the crystalline phases: lanthanide elements such as Ce and Nd constituted similar to 26 wt% of vitusite and 80 wt% of Ce-rich crystals. Amounts of Ce and Nd ions released in a product consistency test were below the detection limit (0.1 ppm) of inductively coupled plasma atomic emission spectroscopy. Glass-ceramic wastefonns that contain vitusite crystals are good candidates to immobilize lanthanide wastes generated by pyro-processing. (C) 2015 Elsevier Ltd and Techna Group S.r.l. All rights reserved.