DEVELOPMENT OF MULLITE- CARBON REFRACTORY CERAMIC COMPOSITE FROM LOCALLY SOURCED MATERIALS

Abstract

In the pursuit of developing a mullite- carbon refractory ceramic composite with optimum physical and mechanical properties modified with additives, experimental studies were carried out using local materials from Nigeria's south-south and south-west regions. Kaolin clay was crushed to 2 mm and ball-milled into powder. Ground kaolin was homogeneously blended with graphite using a ball mill and sieved through a 300μm electric sieve. The homogeneous mix was combined with predetermined Magnesium Oxide proportions, compacted, and fired at 1300 °C, 1400 °C, and 1500 °C. Extensive tests followed, including X-ray diffraction (XRD) for phase analysis, ultra-high- resolution field emission scanning electron microscopy equipped with energy-dispersive spectroscopy (SEM-EDS) for microstructural morphology, and assessments of mechanical and physical properties. Findings indicated that additive inclusion spurred mullite phase development between 1300°C and 1500°C, enhancing their physico- mechanical properties. Among the samples, Sample R composed of 15% MgO, 65% kaolin, and 20% graphite, fired at 1500°C, displayed optimal physico-mechanical properties (95.8%) and favorable mullite formation (46.0%) was achieved.