Optimization of binder matrix in high alumina based low-cement castable refractories

The main objective of this study was to investigate the optimization of the binder phase of low cement alumina based castable via addition of MA spinel and SiC and observe the changes in the basic refractory properties. In the preliminary stage of the study, 3 low cement castable formulations were designed, based on white fused alumina, tabular alumina, and mixtures of them to determine main aggregates in the formulations. The best results were obtained with tabular alumina aggregates. Main castable formulation was determined after using Andreassen module for the particle size distribution and after preliminary sintering temperature trials. In the first stage of the experimental work, the effect of MA spinel addition which has high corrosion and thermal shock resistance on the high alumina castables was investigated. As a result of the physical, thermal and mechanical tests showed that 10% MA spinel addition were found to improve the technical properties of the castables among of other additive contents. In addition it showed high performance against slag resistance besides cold compressive strength values as high as 172 MPa by addition 10% spinel. At the second stages of the experimental studies, effect of SiC addition on the properties of castable was investigated, because SiC has better wetting properties for the refractories and high corrosion resistance. In addition, combined effect of MA spinel and SiC addition was also investigated. It was concluded that, MA spinel addition to the low cement high alumina castable strongly improved the refractory properties.