Influence of gel-derived nanocrystalline spinel in a high alumina castable: Part 1

A newer class of spinel-alumina castable was fabricated by incorporating 8.0 wt.% of modified spinel additives synthesized via sol–gel and coprecipitation methods. These additives prepared by cheaper ingredients after optimum grinding and calcination, were characterized in terms of particle size distribution, infrared spectra and X-ray diffraction patterns. The properties of those spinel-alumina castables, with another prepared by the same amount of commercial preformed spinel fine, were studied and compared. Cold crushing strength, apparent porosity, hot modulus of rupture, pore size distribution, scanning electron microscopy, energy dispersive spectral analysis, thermal shock and slag corrosion resistance tests of selected samples were done to identify the immense prospect of sol–gel additive. Transmission electron microscope (with SAED facility) was also utilized to establish the nanocrystalline feature of the sol–gel additive.