Studies of portions of the quaternary system soda-lime-silica-water at 25 degrees C

Abstract

A study has been made of portions of the system soda-lime-silica-water at 25 C. The only solid phases found were Ca(OH)2 and a four-component gel of variable composition. The boundary, Ca(OHh-soda-lime-silicate gels, was determined and the compositions of the gels along this boundary shown to vary from 0.003Na20:2.OCaO: 1.0Si02 :xH20 (at 0.2 g of Na20 per liter) to about 0.25Na20:-1.0CaO: 1.0Si02 :xH20 (at 20 g per liter and extending to 101 g per liter of Na20). In regions off the boundary, at selected constant concentrations of Na20 but with increasing concentrations of Si02 in solution, the Na20:Si02 molar ratio of the gels varied only slightly from 0.2 in most cases; the CaO: Si02 molar ratio, however, decreased to values approaching 0.1 at the maximum concentrations of Si02 used. Interpretations pertaining to relations between the composition of the gels and solutions are given.