Examples from recent decades recount great progress in engineering of refractories. Reducing calcium aluminate cement by adopting silica fume and ultrafine alumina powders in refractory castables greatly improved their high-temperature properties and helped shift a large fraction of refractories from prefired bricks to in-situ installed castables.¹ Replacing conventional carbon sources with nanoscale carbon brought about low-carbon refractories, leading to reduced carbon pick up in steel refining processes.² Mullite formed in-situ instead of admixed in the refractory matrix achieved much higher strength and thermal shock resistance for refractory products.³ Use of nanosized silica improved flowability of castables.⁴

Further, a variety of new additives incorporated into shaped and unshaped refractories helped optimize phase distribution, structural bonding, damage resistance, etc. For example, organic-based dispersant helps improve the dispersion of ultrafine silica and alumina powders in castables;⁵ boride- and carbide-based antioxidants help protect carbon from oxidation in carbon-bonded refractories;⁶ barium-containing additives in aluminosilicate refractories improve corrosion resistance against aluminum melts;⁷ and small amounts of alumina in nitride-bonded SiC refractories can improve strength by changing grain morphology.⁸