Solubility and Valence Variation of Ce in Low-Alkali Borosilicate Glass and Glass Network Structure Analysis

Liu Yang; Yongchang Zhu; Jichuan Huo; Zhu Cui; Xingquan Zhang; Xuanjiang Dong; Jie Feng

doi:10.3390/ma16145063

Solubility and Valence Variation of Ce in Low-Alkali Borosilicate Glass and Glass Network Structure Analysis

Materials (Basel). 2023 Jul 18;16(14):5063. doi: 10.3390/ma16145063.

Authors

Liu Yang¹, Yongchang Zhu^{1

2}, Jichuan Huo^{1

3}, Zhu Cui², Xingquan Zhang^{1

3}, Xuanjiang Dong², Jie Feng¹

Affiliations

¹ State Key Laboratory of Environment-Friendly Energy Materials, School of Materials and Chemistry, Southwest University of Science and Technology, Mianyang 621010, China.
² China Building Materials Academy, Beijing 100024, China.
³ Fundamental Science on Nuclear Wastes and Environmental Safety Laboratory, Southwest University of Science and Technology, Mianyang 621010, China.

Abstract

Low-alkali borosilicate glass was used as the immobilization substrate, and Ce was used to replicate the trivalent and tetravalent actinides, in order to create simulated waste glass through melt heat treatment. The valence of Ce and solubility of CeO₂ in waste glass were studied as well as its network structure and thermal and chemical stability. The solubility of Ce in waste glass was examined by XRD and SEM. The network structure was examined by Raman spectroscopy. The valence of Ce was determined by X-ray photoelectron spectroscopy. Thermal analysis and product consistency (PCT) were employed to determine the thermal and chemical stability of waste glasses. The results show that the solubility of cerium in low-alkali borosilicate glasses is at least 25.wt.% and precipitates a spherical CeO₂ crystalline phase when it exceeds the solid solution limit; Ce is immobilized in the glass by entering the interstices of the glass network. Depolymerization and the transition from [BO₃] to [BO₄] occurs when CeO₂ doping levels rise. About 60 percent of Ce⁴⁺ is converted to Ce³⁺, and the thermal stability of glass rises then falls with the increase of CeO₂. All samples exhibit strong leaching resistance, with the average mass loss of Ce at 28 days being less than 10^-4 gm^-2d^-1.

Keywords: Raman; XPS; cerium; low-alkali borosilicate.

Grants and funding

This research was supported by the National Defense Key Discipline Laboratory of Nuclear Waste and Environmental Safety, China, Grant number 17kfk03, and the State Key Laboratory of Environmentally Friendly Energy, China, Grant number 21fksy11.