The paper analyses the influence of cigarette butts and waste coffee grounds addition on the properties of the brick clay. The waste materials were added to the clay in amounts of 5 wt.% and 10 wt.%. Standard consistency, plasticity, drying and firing behaviour and refractoriness were tested on the clay sample and the samples with wastes additions. Apparent density, apparent porosity, water absorption, strength and thermal conductivity were investigated on the samples fired at 1173 K. Addition of the waste materials improved thermal insulation characteristics and drying shrinkage, while other properties remain within the required limits for brick industry.

In this paper are investigated microstructural, phase, physical and mechanical properties of mullite ceramics obtained from clay and Bayer electrofilter fines. Clay and alumina were mixed in such ratio that provides the amount of Al2O3 and SiO2 corresponding composition of mullite. One mixture was manually mixed and other was milled three hours in ceramic mill. After isostatic molding and heat treating at 1580°C and 1635°C XRD analysis revealed approximately 60% of mullite and 40% of corundum in first mixture and in second mixture 70% of mullite and 30% of corundum. Two types of mullite were observed in SEM micrographs beside corundum grains and glassy phase. The results of investigation indicate that preparation of mullite ceramics from these raw materials is possible, if clay and alumina are well homogenized and milled before molding.