Bagasse and rice hulls ash are both waste materials. In recent years, in order to meet environmental protection, these materials have been recycled in the production of porous ceramics. A solid-state reaction mechanism of calcined alumina and talc was used to prepare cordierite-spinel porous ceramics. Talc was added from 30 to 60 wt.% at the expense of alumina and sintered at 1400 • C for 2 h. The effect of bagasse and rice hulls ash (as a pore forming agent) on the densification parameters, cold crushing strength (CCS), and pore size distribution was also studied. The phase composition (X-ray diffraction) and microstructure (scanning electron microscopy) of sintered samples were investigated. The results showed that the main phases present in the samples are cordierite, corundum, spinel, and sapphirine. In the sample with a higher amount of talc additions (60 wt.%), only the formation of the cordierite and spinel phases was observed. The bulk density of the samples and the apparent porosity ranged from 1.77 to 2.26 g/cm 3 and from 28.6% to 48.21%, respectively. The CCS of the samples ranges from 13.9 to 36.3 MPa. The microstructures of the sintered samples were observed for the formation of cordierite phase, alumina phase, and spinel phase in an excellent crystallization and phase arrangement.

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In this study, we investigated the effect of sintering temperature and nano boehmite additions on the phase composition, densification, and mechanical properties of porous cordierite ceramics. Ceramic samples were sintered at temperatures ranging from 1200 to 1400 • C. Carbon powder was used as a pore forming agent to improve the porosity of the ceramic structure. Nano boehmite and carbon additions significantly enhanced ceramic porosity and average pore size in sintered samples. The bulk density and apparent porosity of the sintered samples were found to be 0.96-1.53 g/cm 3 and 42.3%-65.6%, respectively. Sintered samples had cold crushing strengths of 1.5-14.3 MPa. The microstructure obtained by scanning electron microscopy was used to measure average pore size in sintered samples and was found to be 41.93 µm for stoichiometric composition (SC), 67.72 µm for SC and nano boehmite, and 102.98 µm for SC, nano boehmite, and carbon. The microstructure of the sintered samples revealed that the crystallinity of the in situ formed phases increased with the increase in nano boehmite additions.

The preparation of highly efficient and low cost abrasive stones has gained considerable interest in the last few years from the industrial and academic research societies. Meanwhile, composition of such abrasive stones material has played a significant role on its physicochemical, mechanical properties and cost. In this work, series of magnesium oxychloride cement samples were prepared by adding MgCl2 solutions to magnesia, where H2O/MgCl2 was 13:1, 15:1, and 17:1, while MgO/ MgCl2 molar ratio was fixed at 7:1 for all samples. During mixing, two grades of SiC were added separately in proportions of 20, 25, and 30 mass percentage. A comprehensive characterization including bulk density, compressive strength, abrasion resistance, and polishing performance were carried out to the prepared composites samples. This was followed by studying their mineral composition and the possible use in grinding and polishing processes of marble slabs. Interestingly, the obtained characterization results demonstrated that among the different prepared composite materials, 25 mass percent SiC‐containing samples showed the best physicochemical and mechanical properties. Notably, the degree of fineness of SiC has affected the overall properties of SiC composite. When very fine SiC type was used and the water content was reduced, consequently, the samples bulk density and abrasion resistance increased. Phase 5 (5Mg(OH)2.MgCl2.8H2O) and silicon carbide, as the main phases with a minor amount of magnesia, were detected in the samples. From the economic point of view, the obtained result in our study is promising for its high performance‐low cost for grinding and polishing of marble slabs in the industrial fabrication.