Effects of particle size of Al(OH)₃ on the properties of porous purging materials

Abstract

Porous purging plug is promising in the course of steel-making especially for producing the pure steel. Five designed castables containing the same aggregates and different matrixes were fabricated successfully. Air permeability tests, microstructural characterization and grey incidence analysis were carried out to analyze the particle size of aluminum hydroxide [Al(OH)₃] effects on the properties of porous purging materials. According to the attained results, the smaller particle size of Al(OH)₃ seemed to be suitable to improve the properties of such materials, as it induced the formation of connected pores and hot modulus of rupture changed slightly. When the particle size was 36.1 µm, the air permeability could reach 13.4 µm². Moreover, the grey incidence analysis matched to the experimental observations, attesting the smaller particle sizes (10–20 µm) were helpful for enhancing the air permeability while the bigger particle sizes (≥100 µm) had the opposite effects.