Basic oxygen furnace (BOF) slag is a main byproduct produced during the converter steelmaking process. The poor grindability of BOF slag limits its added-value application. In this paper, the grinding characteristics of unmodified and reconstructed BOF slag were compared. Additionally, the grinding property of reconstructed steel slag was also studied after SiC foaming. The results show that the solid solution of divalent metal oxides’ RO phase, considered as the hardly grinding phase, discomposes after lime-bauxite reconstruction. The characteristics of BOF slag were tested through particle size analysis, XRD, SEM and MIP. The SSA (specific suface area) and the particle diameter of unmodified BOF slag could reach 303.1 m2/kg and 51.75 µm after 10 min of grinding, but that of reconstructed BOF slag could reach 354.5 m2/kg and 18.16 µm after the same grinding time, respectively. The grinding efficiency of steel slag was obviously increased and the particle characteristics were improved after foaming modification. BOF formed as a porous structure after SiC foaming; its porosity, SSA, and particle diameter can reach 31.79%, 424.4 m2/kg, and 24.36 μm and increased by 10.31%, 19.72%, and 39.04%, compared with the reconstructed steel slag of undoped foaming agent, respectively, and the grindability was further improved. A theoretical basis for large-scale BOF slag utilization is provided.

Poor utilization of ceramic polishing slag and uneven foaming at high temperatures are some of the crucial problems associated with the formation of porous ceramics. To overcome this, the present study was designed to prepare closed-ended polishing slag porous ceramics by controlling the holding time. Scanning electron microscope, XRD, and X-CT were used to investigate the effects of holding time on the microstructure, pore structure, and phase composition of porous ceramics. The results showed that the holding time had a great influence on the physical properties of the samples, and it provides uniform porosity without significant change in the composition of the material phase of the porous ceramics. Under a holding time of 30 min, volume density reached up to 0.68 g/cm3, while the water absorption and the apparent porosity were 27.33% and 15.49%, respectively. The compressive strength reached 13.07 MPa, and the pore size distribution is mainly between 25 μm and 100 μm, of which the d30 pore diameter accounted for about 28%, the d50 pore diameter accounted for 25%, the d70 pore diameter accounted for 12%, and the d90 pore diameter accounted for 10% of the pore size distribution. In conclusion, the present study clearly shows that the pore structure and properties of porous ceramics can be effectively controlled by controlling the holding time while using a high volume of polishing slag. The feasibility of X-CT for studying the pore distribution inside porous ceramics was verified.