Generation of Pyroxene-Based Porous Ceramics from Steel Refining Slag

In this paper, porous ceramics were prepared by controlling the composition and sintering temperature of raw materials based on slag from steel refining operations and without the need for a pore-forming agent. Solid-state processing included a phase transformation from low-density raw materials (2.10–2.90 g/cm3) to high-density pyroxene-based ceramics (3.22–3.88 g/cm3). Phase transformations and densification of porous ceramics were investigated by means of mercury intrusion, XRF, SEM and EDS. Results showed that a porous ceramic with optimum properties produced from raw material containing 35 wt.% steel refining slag, exhibited a high water absorption capacity of 31.62%, flexural strength of 18.26 MPa, porosity of 44.5% and an average pore diameter of 1.27 µm. Raw materials with high fineness or content near the pyroxene composition promoted formation of pyroxene and accordingly more volumetric shrinkage which enhanced both bending strength and porosity of the porous ceramics.