Materials Research Bulletin, Vol.43, No.7, 1679-1693, 2008
Sulphate incorporation and glass formation in phosphate systems for nuclear and toxic waste immobilization
Glass formation and the capacity for sulphur incorporation have been investigated within the systems P2O5-Al2O3-Na2O-Fe2O3 and P2O5-Fe2O3-RyO (R = Li, Na, K, Mg, Ca, Ba, Pb). Linear relationships have been identified linking log [SO3] with the oxide ion activity, which can be represented to varying degrees by normalized cation field strength index Sigma(z/a(2)), theoretical optical basicity Lambda(th), oxygen to phosphorus molar ratio [O]/[P], or P2O5 content. When prepared under oxidizing conditions only basic, highly depolymerized phosphate glasses for which Sigma(z/a(2)) < similar to 1.2; Lambda(th) > similar to 0.5; [O]/[P] > similar to 3.8; or P2O5 content