Influence of the increased content of Calumite blast-furnace slag on the melting of sodium–calcium–silicate glass

Abstract

A glass set with a high content of blast-furnace slag and a reduced amount of traditional raw materials requires optimization of the raw material composition and adjustment of its specificity to the temperature regime of melting, homogenizing and clarifying the glass mass. The introduction of an increased amount of blast-furnace slag allows to reduce the cost of raw materials: soda, limestone and high-class sand, reduce energy costs, whose consumption significantly decreases and reduces CO2 emissions in line with EU requirements. The tests of thermal analysis of a glass set with different contents of Calumite are aimed at learning the mechanism of its operation by determining the changes caused by its different presence in the course of subsequent reactions between the components of the glass set. Analysis of the influence of the addition of different Calumite slag contents treated as a substitute for the raw material on the melting process of glassware sets was analyzed. The tests were carried out using differential thermal analysis (DTA) and thermogravimetry (TG) based on the model glass [mass%]: 73.0% SiO2, 1.0% Al2O3, 10.0% CaO, 2.0% MgO and 14.0% Na2O. The effect of combining Calumite with sulphate and multi-component fining agent—mixtures of As2O3, Sb2O3, NaNO3 in proportions of 1:1:1 for chemical reaction and phase transformation, was investigated.