Investigation in CaO–SiO <sub>2</sub> –CaF <sub>2</sub> –C slags during the sintering and melting process
Liang Yu, Wenbo Jiang, Shaopeng Gu, Ping Tang, Zhe Wang, Guanghua Wen
Abstract
The reaction behaviour and mechanism of carbon and mould fluxes during the heating process were deeply considered through TG-FTIR, XRD, DSC, and SEM techniques. The results showed that: there were four main stages of weight loss for slags during heating process. One hundred to 300 °C and 300–500°C were the volatilization of free water and bound water, respectively. Five hundred to 800°C was the decomposition process of carbonate. However, at 800–1400°C, CaO–SiO2–CaF2 slag was the reaction of slag component themselves. CaO–SiO2–CaF2–C series slags were the reaction behaviour between carbon and slags (C and Ca2SiO4, Ca4Si2O7F2). The DSC and SEM analysis illustrated that the solid phase reaction temperature range of CaO–SiO2–CaF2–C being 1320–1370°C was larger than that of CaO–SiO2–CaF2 being 1070–1250°C. Additionally, CaO–SiO2–CaF2 slag was completely molten at 1400°C, while CaO–SiO2–CaF2–C did not, suggesting that the sintering and melting process were suppressed by carbon.