Making Use of Red Mud - the Tail of Aluminum - as a Sustainable Building Material

Abstract

Aluminum is a material that is required by many sectors. However, large amounts of waste are generated during its production. According to the data for 2019, approximately 130 million tons of waste red mud were generated worldwide with the production of aluminum. In Turkey, waste red mud occurs at Seydisehir ETI aluminum factory. The resulting waste red mud is kept in storage areas close to settlements. Such a high rate of waste red mud poses a threat to the immediate surroundings of storage areas. As a result of an accident in the aluminum tailings pond located in Aijka, Hungary, waste was transported along the rivers, which turned into an environmental disaster. Therefore, hundreds of studies have been carried out to make use of the waste in such a high amount in some way. However, most of the studies conducted are on the part of the waste content or indicate that it can be used as an additive at low rates to different materials. Studies on making use of the whole of the waste as the main material have remained limited. Based on this deficiency, red mud waste was used as the main raw material in the production of baked building materials for systematic consumption in this study. However, from the literature review and preliminary experimental studies on red mud, it was understood that the waste could not be a quality material on its own. Thus, it was thought that the addition of pyroclastic rock to be obtained from inert sites, with red mud being the main raw material waste, would be appropriate. Accordingly, in this study, pyroclastic rocks obtained from Konya Selahattin Village, around Konya Selcuk University Campus, and from Konya Karapinar regions were added to the red mud obtained from Seydisehir ETI Aluminum factory at the rates of 10%, 20%, 30%, 40%, and 50%. Samples obtained with these mixing ratios were baked at 930, 1000, and 1050 degrees C. Due to the capillary cracks observed on the backed samples, 3% bentonite was added to the mixture. As a result of the preliminary tests conducted on the samples obtained, two mixture types from each region that reached the best compressive strength were selected. Experiments were carried out to determine the physical and mechanical properties of the samples obtained from the selected mixture types. Through the experiments, it was determined that the samples baked at 1050 degrees C by adding 20% of pyroclastic rock obtained "Karapinar Region black-colored slag" to red mud were the optimum mixture type due to yielding better results compared to others in terms of both physical and mechanical properties. As a result of the study, it was concluded that it was possible to use the waste at high rates and thus, the waste could be consumed systematically. Thanks to the baked building material produced with the findings obtained in this study, a contribution was made to the reduction of a potential environmental problem, and a local contemporary building material was obtained for sustainable building material needs.