The microstructure of a clay ceramic added with blast furnace sludge, a residue generated at integrate steel making plants, has been analyzed. This analysis was performed by means of optical microscopy and scanning electron microscopy coupled with energy dispersive spectroscopy. The green clay body was added with 5 and 10 wt% of blast furnace sludge. A pure clay body was also considered as reference. These clay bodies were fired at 750°C and 950°C. The results indicated that the ceramic microstructure is non-uniform with both residue particles and pores dispersed throughout the clay matrix. Microcracks are also observed as a consequence of weak adhesion of the residue to the clay. At the higher firing temperature of 950°C the microstructure displayed a smoother surface due to the formation of low melting phases.
Upgrading of Blast Furnace Sludge and Recycling of the Low-Zinc Fraction via Cold-bonded Briquettes
