Structure, viscosity, and crystallization of glass melt from molten blast furnace slag

Abstract

Abstract Molten blast furnace slag (BF slag) was modified using liquid‐liquid mixing method for glass ceramics preparation, and the structure and viscosity of glass melt after modification were investigated. The BF slag proportion increased from 52.72 wt. % to 67.05 wt. %, and CaO/(SiO 2 + Al 2 O 3 ) also varied from 0.33 to 0.47. The structure of BF slag melt after modification was investigated using 29 Si and 27 Al MAS NMR spectra. With increasing CaO/(SiO 2 + Al 2 O 3 ), the amount of Q 1 remarkably increased while that of Q 2 decreased significantly. Specifically, when CaO/(SiO 2 + Al 2 O 3 ) was more than 0.38, Q 3 disappeared in glass melt. The viscosity of glass melt with CaO/(SiO 2 + Al 2 O 3 ) of 0.47 exhibited a steep change at 1169°C, which was mainly caused by the sufficient crystallization of gehlenite confirmed by DTA cooling analysis, XRD, and FE‐SEM‐EDS analysis.