Some Study related to Refractory Waste Management in Sweden : A move towards a greener and sustainable Swedish steel industry
Abstract: Decades ago, 1 ton of steel required 80 kg of refractory material. While the scenario has completely changed over the years. Today, 1 ton of steel needs approximately 11 kg of refractory material depending on the steelworks. Refractories are accustomed to high-temperature processes, for example, producing steel, glass, etc. The amount of spent refractories has also increased with the increase in demand for its production. For the manufacturing of refractories, there is a tremendous use of virgin raw materials but with the increase in price and reducing raw material sources, it will be difficult to continue in that way in the future. While, the environmental concerns in steel industries are increasing on a rapid scale such as global environmental pollution, natural resource conservation, and the most important increase in cost for landfilling. Therefore, achieving zero waste and proper usage of material from spent refractories is necessary for economic and environmental reasons in future. This project work focuses on collecting information regarding the refractory waste management for aid towards more sustainable Swedish steel industries. The project is carried out in collaboration with KTH Royal Institute of Technology and the Swedish steel producers association Jernkontoret. This work focuses on a survey of well-known Swedish steel companies Sandvik Materials Technology (SMT) AB and Höganäs AB. The scientific work concentrates on the investigation of MgO-C bricks mixed waste, collected from Mireco AB, up to a grain size of 20 mm. Three samples of varying compositions and different grain sizes were collected from the recycling site and processed for carbon reduction. On several trails, the maximum carbon elimination was achieved at a temperature higher than 800°C with holding time longer than 5h. The fines underwent mechanical pressing of 40 MPa to form pellets of 16 mm and 32 mm in diameter. The main traced elements of MgO, SiO2, CaO, Al2O3 and Fe2O3 can be utilized for applications in the agricultural industry. MgO is present in the maximum quantity (70-80%). By possible extraction of MgO from the fines can be employed in the crucible industry, construction industry and steel industry for slag formation. The MgO in the form of supplements for magnesium deficient soils or calcium magnesium oxide for neutralizing the pH of the soil by balancing the acidity can be employed. The compatibility of the fines can be helpful to resolve transportation issues and benefit convenient addition to processes. Overall, this work brings to the fore a high potential for using such waste refractory materials forapplications besides landfilling with an emphasis on agriculture.
AT THIS PAGE YOU CAN DOWNLOAD THE WHOLE ESSAY. (follow the link to the next page)