Preparation of foamed ceramics from steel slag with high calcium and iron content

Abstract

AbstractIn this paper, steel slag foamed ceramics were fabricated by using steel slag, kaolin, feldspar, and quartz as main raw materials, and adding SiC as high‐temperature foaming agent. The effects of steel slag content and SiC particle size on porosity and mechanical properties of foamed ceramics were researched. Results indicate that when content of steel slag is 40 wt%, and particle size of SiC is 20 µm, foamed ceramics exhibited optimized properties: water absorption rate of 2.59%, total porosity of 55.91%, bulk density of 1.33 g·cm−3, and compressive strength of 1.21 MPa. The results show that with the increase of steel slag content, the phase composition of foamed ceramics changes, and foam process is hindered. The increase of steel slag content contributes to the formation of diopside. Fe3+, Fe2+ in liquid phase enter into diopside by solid solution, the amount of liquid phase decreases. Liquid phase mass transfer slows down, and content of SiC in liquid phase decreases, so that the porosity decreases. At the same steel slag content, different SiC particle size affects the difference between pressure inside the closed pore and surface pressure, thereby the porosity changes.