Submicron SiO₂ Powder: Characterization and Effects on Properties of Cement‐Free Iron Ditch Castables

Abstract

Submicron materials are those with particle size diameters between 0.1 and 1 μm. Submicron SiO2 generally refers to SiO2 powder with a D90 < 1 μm (D90 refers to the particle size distribution exhibited by the sample and corresponds, in this case, to 90% of the particles not exceeding a diameter of 1 μm). In this study, a new type of cement-free iron ditch castable was prepared using dense corundum and silicon carbide as the primary raw materials with submicron SiO2 powder as the binder. The effects of submicron SiO2 powder content on the bulk density, apparent porosity, linear rate of change, compressive strength, and bending strength were investigated. The mechanism of action of the submicron SiO2 powder was also investigated by analyzing its microstructure and particle size distribution. The results revealed that (1) the submicron SiO2 powder can be used as the sole bonding agent in the preparation of cement-free iron ditch castables; (2) in comparison to traditional castables, the cement-free castable developed in this study demonstrated strong service performance and high-temperature bending strength.

Enhanced performance of Al2O3–SiC–C castables via in-situ formation of multi-reinforced phases by introducing surface treated composite metal powders

“…As for the second aspect, the addition of metal powders can not only improve the oxidation resistance of ASC castables, but also enhance its explosion resistance. Its anti-explosion mechanism is that the addition of metal powders increases the open pores or/and microcracks inside the ASC, which makes the steam in the ASC easily escape.However, previous studies have shown that adding metal powders can reduce the strength of castable although it has a good explosion resistance effect [22]. Therefore, in practical applications, the amount of metal powders added to ASC castables must be controlled to a very small level.…”