Effect of SiC powder content on lightweight corundum-magnesium aluminate spinel castables

摘要

This study investigates five lightweight corundum-magnesium aluminate spinel castables (LCSC) which consisted of porous corundum-spinel aggregates and matrices with 0-2.8 wt% silicon carbide (SiC). The effect of the SiC powder content (SPC) in the matrix on the microstructure, strength, thermal conductivity and slag resistance was analyzed by XRD, SEM and EDS as well as by the thermochemical software FactSage. The addition of SiC powder resulted in a significantly improved interface bonding between the porous aggregates and the matrix enhancing the strength and slag resistance. Whereas the thermal conductivity at 300 degrees C and 500 degrees C remained unchanged, it increased significantly at 800 degrees C and 1000 degrees C. The optimized LCSC contained 1.9 wt% SiC powder which combined a suitable apparent porosity (32.5%), a low bulk density (2.41 g/cm(3)), a high flexural strength (17.62 MPa), a high compressive strength (100.76 MPa), a low thermal conductivity (0.978 W/m.K, 1000 degrees C) and a high slag resistance. (C) 2018 Elsevier B.V. All rights reserved.