Reaction of sodium metaphosphate with magnesium and calcium oxides and their mixtures

Abstract

An investigation of the reaction of aqueous solutions of sodium metaphosphate with the refractomy oxides of magnesium and calcium and their mixtures over a wide temperature range is of considerable practical significance for an elucidation of the mechanism of the formation of magnesia concretes with sodium phosphate binders. The investigation was carried out by derivatographic, x-ray, and IR-spectroscopic methods.The starting components were an aqueous solution of sodium metaphosphate NaPO 3 produced by dissolving analytically pure monosodium phosphate in water, CaO produced by calcining CaCO 3 of extreme purity at 1200~ analytically pure reactive MgO, and the electrofusion products of the various grain-size fractions.Suspensions of Mg(OH)2, Ca(OH)2 and their mixtures [Mg(OH) 2 + Ca(OH)2 ] were added to the Nal~:~ solution. The suspensions were prepared by dissolving the calcium hydroxide and reactive magnesium oxide in water.The resulting liquors were dried at 120~ with constant stirring. The resulting powders were molded into tablets which were fired at various temperatures. The composition of the investigated mixes is given in Table 1.

Effect of liquid phase on sintering of magnesium oxide with zirconium diphosphate addition.

“…This process will continue until the smaller grains disappear and will produce uniform grains14). 4.…”