Structure and Thermal Properties of High-Alkali Molybdenum-Containing Borosilicate Host Materials

Effect of Phosphorus on Crystallization of Alkaline Molybdenum-Containing Borosilicate Glasses

“…The glasses for this study were synthesized from the "analytical grade" SiO2, "high purity grade" B2O3 and "chemical purity grade" Li2CO3, Na2CO3, K2CO3 NaH2PO3, K2HPO3 and MoO3 by melting the components in the platinum crucible at 1200-1250 °C and rapid cooling (quenching) of the resulting melt according to the method described earlier [18,[21][22][23]. All samples have designations reflecting the elements included (Table 1 and Table 2).…”

“…The thermal stability of the glasses was examined by heat treatment (annealing) for 4 hours in platinum crucibles according to the method described in [18,23]. The annealing temperature used was 600 °C, which roughly corresponds to the temperature of the beginning of the exothermic effects accompanying the crystallization processes in these samples.…”

“…% MoO3 in borosilicate glasses that used in the immobilization of radioactive waste [1][2][3][4][5][6][7] is always accompanied by the formation of molybdate crystalline phases with low hydrothermal stability [8][9][10][11][12][13][14][15][16][17]. In our previous study of the glassceramic materials obtained by rapid cooling of highly alkaline molybdenum-containing melts of the Li2O-(Na2O-K2O)-MoO3-B2O3-SiO2 system, it was found that almost all of the molybdenum consumed to form crystalline phases: Li2MoO4, Na2MoO4, KLiMoO4, or K2MoO4 [18]. This is accompanied by the change in the chemical composition and degree of polymerization of the amorphous part.…”