Chemical Durability, Properties and Structural Approach of the Glass Series xFe₂O₃-(45-x) PbO-55P₂O₅ (with 0 ≤ x ≤ 20; mol%)

Abstract

The synthesis for glasses series xFe 2 O 3 -(45-x)PbO-55P 2 O 5 , (with 0 ≤ x ≤ 20; mol%) carried out in a temperature (1050 ± 10) ° C, leads to obtaining transparent glasses, brown in color and with a non-hygroscopic appearance. The study of glasses dissolution rate, immersed in distilled water at 90 ° C for 24 days, indicates a considerable chemical durability. The increase in the Fe 2 O 3 content in the vitreous network to the detriment of PbO is a favorable factor for the chemical durability improvement. Different techniques have been used such as X-ray diffraction, infrared spectroscopy, DSC, SEM and density for the study of these glasses. These techniques have led to establish correlations between chemical and structural properties. Thus the results obtained confirmed the creation of P-O-M bonds (M = Pb, Fe) with a strongly covalent nature to the detriment of the hydrated P-O-P bonds and led to the formation, mainly, of pyrophosphate groups. The low melting point of Pb-O makes it possible to play an important role, at the same time, on the viscosity, on the equilibrium between the vitreous bath and the crystallites formed. The dissolution rate obtained is 100 times smaller than that of silicate glasses used as an alternative form for the vitrification of radioactive waste.