Manufacture of building materials using local raw materials and industrial wastes as an effective production approach for developing building materials while minimising environmental impact
The present article analyses the possibility of using local raw materials and industrial waste (clay from the Ziminsky deposit and ash from the Novo-Ziminsky thermal power station) in the production of structural ceramics. Drawing on the research results, optimal technological indicators were determined along with the main physical and mechanical characteristics of the obtained material. The relative strengths of ceramic fragments made from pure clay and clay mixed with ash were compared. In order to determine the chemical composition of the ash and clay under study, X-ray fluorescence analysis was performed to assess the quality of raw materials used in the production of structural ceramics. The structural characteristics of the studied raw materials (mineral composition) were determined using X-ray phase analysis, whereas the strength of the obtained samples was assessed through the direct method of destruction employing an IP500 press. In addition, the following clay characteristics were assessed using a standard procedure, i.e. particle size distribution and plasticity, as well as physicomechanical properties (density, water absorption, fire shrinkage and compressive strength of the resulting clay fragment). Next, the possibility of mixing clay with 15% ash was evaluated, followed by an assessment of the strength of the resulting ceramic fragment. The kinetics of changes in the relative strengths of obtained samples were studied according to several factors (compacting pressure, moulding water content of the mixture and firing temperature). Following the experiments, the results were presented in the form of plots reflecting the correlations between strength and the above-mentioned factors. According to the study results, it was possible to obtain structural ceramics including ash, which met the strength requirements set out in regulatory documents, whereas the quality of its surface made it suitable for use as a facing material. The optimum of the main technological indicators (moulding water content, compacting pressure and firing temperature) was determined.