Effect of ZrO₂ addition on water durability of FeO–Fe₂O₃–P₂O₅ glasses

Abstract

We have studied the water durability of ZrO₂ containing FeO–Fe₂O₃–P₂O₅ glasses for the immobilization of nuclear waste including Zr isotope. ZrP₂O₇ crystals with 1–2 micrometer in diameter were precipitated in the glass matrix incorporated with ≥1 mol % ZrO₂. The molecular structure of phosphate network including ZrP₂O₇ precipitates was analyzed by micro-Raman spectroscopy. Formations of Q¹ and Q⁰ phosphate units contributing to better water durability are ascribed to preferential precipitation of ZrP₂O₇ crystals with Q¹ units and the compensation of phosphate component in residual glass matrix.