Synthesis, heating, and melting of stoichiometric glass (CaSiO3·SiO2)

Abstract

Thermodynamic analysis (TERRA program) of synthesis, heating, and melting of stoichiometric glass CaSiO3·SiO2 has been carried out. Chemically pure substances silica and lime are subjected to exothermic reaction with further external heating and melting. Wollastonite is synthesized, the chemical reaction generates heat Q chr = −505.3 kJ/kg, and temperature increases T = 820 K. When T melt = 1812–1814 K, wollastonite melts, and a mixture of liquid wollastonite and condensed silica is formed. At T melt = 1995–1997 K, silica melts, and stoichiometric glass (CaSiO3·SiO2) is formed. Evolutions of temperature and melting of wollastonite and silica have been studied by detailed step-by-step thermodynamic calculation (ΔT = 0.1 K).