Understanding the Relationship Between Structure and Thermophysical Properties of CaO-SiO2-MgO-Al2O3 Molten Slags

作者：Sun, Yongqi; Wang, Hao; Zhang, Zuotai^*

来源：Metallurgical and Materials Transactions B-Process Metallurgy and Materials Processing Science, 2018, 49(2): 677-687.

DOI：10.1007/s11663-018-1178-y

• HIGH-TEMPERATURE SLAGS
• CALCIUM ALUMINOSILICATE GLASSES
• BLAST-FURNACE SLAGS
• MQ-MAS NMR
• RAMAN-SPECTROSCOPY
• SILICATE-GLASSES
• AL2O3/SIO2 RATIO
• HEAT-RECOVERY
• MOLD FLUXES
• AL-27 NMR

In the present work, the relationship between the microscopic structure and macroscopic thermophysical properties in a basic CaO-SiO2-MgO-Al2O3 quaternary system was identified using Fourier transformation infrared, Raman and Al-27 magic angular spinning nuclear magnetic resonance (MAS-NMR) techniques. The Raman spectra quantitatively proved that with increasing Al2O3 content, the concentrations of the symmetric units of Q (0)(Si) and Q (2)(Si) decreased, while those of the asymmetric units of Q (1)(Si) and Q (3)(Si) increased; consequently, the degree of polymerization of the networks increased, which resulted in an increase in slag viscosity. The Al-27 MAS-NMR spectra demonstrated that three structural units of Al atoms, namely, AlO4, AlO5, and AlO6, mainly existed in the networks. With increasing Al2O3 content, the concentration of AlO4 slightly decreased, while those of AlO5 and AlO6 increased; overall, Al2O3 acted as a network former in the present system. The increasing Al2O3 content led to additional AlO6 and Si-NBO-Ca-NBO-Al frameworks, which replaced Si-NBO-Ca-NBO-Si in the networks (NBO: non-bridging oxygen) and induced a change in the primarily precipitated crystalline phase from Ca2MgSi2O7 and Ca2Al2SiO7 to MgAlO4.

• 出版日期2018-4
• 单位南方科技大学