Effect of Al₂O₃ on Monazite Glass-ceramic Wasteform

The effects of monazite glass-ceramic wasteforms containing different Al₂O₃ contents on their structures and properties were investigated. The structure of the glass-ceramic wasteforms was analyzed by Fourier transform infrared (FTIR) and X-radiation diffraction (XRD). The chemical stability of monazite glass-ceramic wasteforms was measured by dissolution rate and inductively coupled plasma optical emission spectrometry (ICP-OES) method. The results show that the chemical stability of monazite glass ceramic wasteforms with 4% (mole fraction) Al₂O₃ and made at 980 ℃ for 3 h is optimal. The 14 d leaching rate of monazite glass-ceramic wasteforms is about 8.1 ng/(cm²•min), which is the lowest in all the samples. The main crystalline phase of the as prepared glass-ceramic wasteforms is monazite. There are a large number of PO₄^3- groups, a small number of P₂O₇^4- groups, and no PO₃^- groups in the wasteforms.