Investigation of the geotechnical properties of red mud waste and the preparation of different polysulfone-based composite materials for use as geosynthetic barriers

In this study, the physical, chemical, mineralogical and mechanical properties of the red mud waste resulting from the production of aluminum from bauxite ore by Bayer process in Seydişehir Eti Aluminum Plant were investigated with experimental studies and the results were compared with the properties of red mud in different countries and the usability of the waste as a filling material in the construction area was evaluated. The potential use of red mud as a construction material raises many questions due to environmental concerns. The first issues that come to mind are the potential to contaminate groundwater with high pH leachate from rainfall and the pH value being unsuitable for fauna and flora. These problems arise not only in the reuse of red mud but also in its storage in tailings dams. Accidents at red mud tailings dams in the past confirm this. The red mud dispersed from the collapsed embankment caused serious environmental problems. Therefore, storage or reuse of red mud by reducing its pH to acceptable levels could be the solution to potential problems. However, the amount of waste stored is quite large and the potential use of the waste in construction will require large quantities of material. Therefore, cheap and practical methods for lowering the pH should be preferred. In this thesis, answers to these problems were also sought. For this purpose, the pH value was lowered by filtering the red mud with distilled water as it is a cheap and practical method. In order to determine the possible effect of pH change on the properties of red mud, the experiments were repeated with red mud samples with lowered pH value and the results obtained were discussed. In the next part of the studies, various composites for geosynthetic barrier purposes were prepared using polysulfone (PSF) as carrier matrix polymer and red mud, bentonite, Eşen clay and pumice as additives. These polymer composites can offer the advantages of both organic polymer and inorganic additives together. In addition to being light, flexible and well moldable like organic materials, polymer composites can also have properties such as high strength and thermal stability like inorganic materials, as well as allowing waste to be utilized since the additives used are waste materials. For this purpose, the mechanical, structural and water permeability properties of the composites prepared using the phase inversion method were investigated and their usability in dams, lakes and solid waste storage areas was evaluated.