The impact of MgAl2O4 nano-particles on the hydration-resistance improvement of dolomite-based refractories

Abstract Today, consumers of refractory products have paid special attention to the use of dolomite-based products (bricks and castables). The reason of this attention can be attributed to the outstanding properties of dolomite-based products such as high refractoriness (more than 2000 °C ), the possibility of purified steel melt, high hot strength resistance, good resistance to corrosion in alkali environment and, most importantly, the low price of these types of refractories. But the problem that partly leads to a limitation of the use of these types of refractory products is their low resistance to hydration. In this study, the impact of magnesium-aluminate spinel nano-particles (MgAl 2 O 4 ) on the microstructure and resistance to hydration of fired dolomite refractory specimens has been investigated. It was showed that spinel nano-particles containing dolomite refractories effectively prevents the hydration and create a dens microstructure compared to dolomite refractory specimen without nano-sized spinel added. The reasons of this modification and improvement are related to the reducing of porosities, voids and grain-boundaries due to the generation of some phases with a low melting point such as CaO.Al 2 O 3 (CA) and3CaO.Al 2 O 3 (C 3 A) in the specimen's matrix with the addition of spinel nano-particles.