Addition impact of nano-carbon black on the performance of MgO.CaO compounds

In the present work, the influence of adding nano-carbon black (0, 0.5, 1, 1.5, 2, 2.5 and 3 wt%) on the performance of MgO-CaO composites is discussed. Physical (bulk density, apparent porosity, and hydration resistance), mechanical (cold crushing strength), and thermo-chemical (corrosion resistance) properties of the specimens were evaluated. After formulation and shaping, all compositions were tempered at 250 degrees C for 12 h. Results indicated that by replacing nano-carbon black (up to 2 wt%) in the MgO-CaO compositions, cold crushing strength values increased and then decreased (from 2.5 to 3 wt%). Also, the use of nano-carbon black increased the hydration and corrosion resistance of the specimen due to (i) covering surfaces of the MgO and CaO grains (ii) creating a dense matrix and reducing porosities, and (iii) formation of high hydration and corrosion resistance phase such as in-situ carbide phase (Al4C3) at operating temperature (1650 degrees C). Generally, results showed that the use of carbon black nanoparticles (even in a small quantity) has a significant effect on the improvement of properties in MgO-CaO composites.