Improved slag resistance of ferrotitanium slag based Al2O3-SiC-C castables: The effect of reaction between SiC and TiO2

Abstract

Ferrotitanium slag is a kind of waste slag produced by smelting ferrotitanium alloy. It has high refractoriness (>1790 ℃) and Al2O3 content (≥70 wt%), which can be used to replace bauxite to prepare Al2O3-SiC-C castables. However, excessive substitution will lead to the decrease of slag resistance of Al2O3-SiC-C castables because of impurities in the ferrotitanium slag. In this paper, the slag resistance of ferrotitanium slag based Al2O3-SiC-C castables was improved by increasing the SiC content. The results showed that the castables with 13 wt% SiC had good mechanical properties. Increasing the amount of SiC was beneficial to improve the slag resistance. SiC content increased from 5 wt% to 22 wt%, the erosion index of dynamic slag resistance decreased from 17.05 % to 11.18 %. During the dynamic slag resistance, the TiO2 in the ferrotitanium slag dissolved in the slag, then the SiC reacted with TiO2 in the slag to form TiC coating on the surface of SiC particles. SiC particles wrapped by TiC widely existed in the reaction layer, which prevented further erosion of the slag. Further, the reaction of SiC with TiO2 to consume TiO2 and generate SiO2 increased the viscosity of the slag in the reaction layer, thus hindering slag penetration.