Indian Journal of Chemical Technology, Vol.19, No.6, 420-426, 2012
A novel binder-free and energy-efficient process for making ceramic tiles using red mud and sericitic pyrophyllite
A new process for utilizing the waste from alumina refinery plant such as red mud in production of ceramic tiles has been developed. Pyrophyllite mineral has been added to the red mud to improve the strength properties. The tiles are produced at comparatively lower temperature (950-1000 degrees C) then the conventional process of making ceramic tiles and without addition of phosphatic binders. Impact strength of the optimized composition of 40-60% (w/w) sericitic pyrophyllite in red mud system meets the acceptable limit of impact strength (19.6 J/m) and other properties for ceramic. The achieved impact strength has been attributed to the densification in the matrix of ceramic tiles due to the formation of new phases like calcium aluminum silicate, iron silicate, potassium titanium oxide and magnetite by thermal reaction and transformation of various mineral phases present in the sericitic pyrophyllite and red mud. The structural features of the red mud have been studied using scanning electron micrographs, exhibiting rhombohedral shaped crystals of calcium aluminum silicate and elongated crystal formation of metals silicates, which provides reinforcement to the ceramic tiles matrix.