Influence of Phosphorus, Barium, and Lead Compositional Variation on the Chemical Durability of a Multicomponent Glass System

Abstract

Glasses were prepared by systematic additions of P2O5, BaO, and PbO to glasses consisting of Al2O3‐B2O3‐(BaO)‐CaO‐Fe2O3‐K2O‐MgO‐Na2O‐(PbO)‐(P2O5)‐SiO2, and their chemical durability was examined by the EPA TCLP test. The addition of about 1 mol% P2O5 to a glass containing 5 mol% PbO increases the normalized lead leach rate (NLLR) by about 40 relative%, but increasing P2O5 to 2 mol% decreases the NLLR to about the NLLR obtained without P2O5. A similar, but more dramatic, behavior with changes in the NLLR of about 300 relative% is obtained by sequential combined additions of 1 mol% each of P2O5 and BaO to a glass containing 1 mol% PbO.

Aluminoborate and aluminoborosilicate glasses with high chemical durability and the effect of P2O5 additions on the properties

“…The replacement of more reactive trigonal borons by more chemically stable tetrahedral borons is consistent with the lower corrosion rates of the P 2 O 5 -modified aluminoborate and aluminoborosilicate glasses. The significance of the proposed mechanism for improved durability is highlighted by the observation that the addition of P 2 O 5 has a negative effect on the durability of the borate-free compositions, e.g., series G8 (Table 1) and reported in the literature [12]. The concentrations of B 2 O 3 and SiO 2 are equal in the G10 and G12 glasses, and P 2 O 5 additions improve the durabilities of both series, consistent with the beneficial effect on the corrosion of the borate groups.…”

“…Phosphate additions can either polymerize or depolymerize a silicate glass network, depending on the relative alkali and Al 2 O 3 contents [12]. The chemical durability of borosilicate glasses usually decreases with phosphate additions, although the durability may increase with the formation of durable crystalline phases on the surface [12]. On the other hand, the addition of Al 2 O 3 improves chemical durability but typically also increases the melting point of glasses.…”

“…For example, for laboratory glassware, this limit is around 10 mol% [11]. The effects of P 2 O 5 on the structures and properties of silicate and borosilicate glasses developed for hazardous waste vitrification applications have been examined [12,13]. Phosphate additions can either polymerize or depolymerize a silicate glass network, depending on the relative alkali and Al 2 O 3 contents [12].…”

“…The effects of P 2 O 5 on the structures and properties of silicate and borosilicate glasses developed for hazardous waste vitrification applications have been examined [12,13]. Phosphate additions can either polymerize or depolymerize a silicate glass network, depending on the relative alkali and Al 2 O 3 contents [12]. The chemical durability of borosilicate glasses usually decreases with phosphate additions, although the durability may increase with the formation of durable crystalline phases on the surface [12].…”