Structure Analysis of Vitusite Glass–Ceramic Waste Forms Using Extended X-ray Absorption Fine Structures

Abstract

Vitusite glass-ceramic waste forms were developed and the local environments of the Nd3+ ions in the waste forms were analyzed using extended X-ray absorption fine structure (EXAFS) spectroscopy. A second shell was observed in the Fourier transform (FT) of the EXAFS Nd D-III-edge spectra with the formation of vitusite crystals in the glass matrix. This second shell was attributed to the presence of the Nd-P and Nd-Na ion pairs constituting the vitusite crystal. The preferred incorporation of Nd3+, P5+, and Na+ inside the crystalline phases surrounded by the glass matrix increased the chemical durability of the glass-ceramics.