Crystallization of glass in fireclay refractories: part II: Detailed study on the mullite crystal content of the ‘synthetic’ glass

A glass of composition similar to that found in fireclay refractories was synthesized and subsequently nucleated with Cr₂O₃, V₂O₅ and TiO₂. These glasses were heat-treated for crystallization of the mullite phase. The mullite content, the crystallization of mullite and the effect of temperature on the rate were investigated. The concentration of the nucleating oxides and the size and charge of their cations influence both the mullite content obtained and the crystallization rate.