Design of ceramic microstructures based on waste materials

The progressive changes in ceramic raw materials during firing processes are a complex area. This is partly due to the large number of raw material characteristics, primarily mineral composition, and partly to the rela- tively inadequate particle distribution in the unfired clay body. The most important starting point is always the optimal raw material composition which should give appropriate physical and mechanical characteristics to the final products after firing processes and should provide an efficient and economical production. The paper analyzes the influence of some additives (fly ashes and waste glass materials) on the development of the ceramic roofing tile microstructure during the thermal treatment. The analyzed raw material mixtures were: the standard raw material mixture (from Kanjiza, Northern part of Serbia) and the modified one, i.e. the mixture of the standard raw material and corresponding additive. The silica phase obtained during the thermal collapse of the clay minerals in the presence of the glass additive bounded better CaO and MgO components released from the carbonates. The crystalline phases like plagioclases were performed in a considerable quan- tity and the products with new physical characteristics were formed.