Leaching and devitrification of lead, molybdenum and phosphorus oxide glasses

Abstract

Morocco has established a prominent industry focused on the transformation and development of its abundant phosphate deposits, valued for their diverse properties. Numerous physic-chemical studies focus on the leaching and devitrification of oxide glasses characterized by the composition yPbO-(1-y)[xMoO 3 -(1-x)P 2 O 5 ], with specific parameters of 0≤y≤0.3 and x values of 0.5 and 0.67. Measurements indicated that the addition of PbO in phosphate glasses, at concentrations from 0% to 30%, affects chemical durability. This was assessed across various solution pHs and dissolution times, utilizing an ammonium acetate solution and grain sizes between 300 to 500 urn, demonstrating the cross-linking effect of lead on the glass framework. A study indicates that the mass losses from the leaching of glasses occur linearly over time, regardless of their composition, and that glasses containing PbO exhibit increased durability. Studying the devitrification of elaborate glasses, this work presents X-ray diffraction analysis results for two glass families (x=0.67; 0.5). The analysis of the crystalline glass composition 0.3PbO-0.47MoO 3 -0.23P 2 O 5 indicates the formation of Pb(MoO 2 ) 2 (PO 4 ) 2 .