| Abstract [eng] |
United Nations in 2015 initiated the Sustainable Development Goals, aimed for solutions to environmental challenges: climate change, limited natural resources, waste. Construction waste accounts for ~40% of the global total, as industrial and household stands for 24% and 21%, respectively [1]. The significant amount of construction sector waste led to increased focus on the development of sustainable technologies, integration of secondary raw materials into production processes. One of the materials widely used in construction is mineral stone wool. During the production process of this material, as natural rocks are melting in the cupola furnace, approximately 20 kg/h of cupola dust is generated and blown out along with gases [2]. This byproduct is not returned to production, therefore dumped into landfills and adds to the general 2,54 million tons of mineral wool waste generated yearly in the European Union [3]. Although cupola dust is landfilled, dust is rich in SiO2, Na2O, CaO, K2O and MgO oxides, which could make them valuable as active filler in composite materials. In this phase, focus is on the formation of the granules and granulation process is a preparatory step for replacing fillers in refractory materials. Produced granules are thermal treated at temperatures up to 1000 °C to assess the chemical, physical and mechanical changes due to exposure to high temperature. Experimental data is obtained through analyses of chemical composition, pH, electrical conductivity and SEM, in order to evaluate granules, influence on the hydration, microstructure and other characteristics on the alumina cement, widely used in refractory applications. It is expected that the developed granules will not only allow the substitution of fillers, commonly used in the industry for aluminate cement in refractory applications but also contribute to a more sustainable production of building materials by reducing the need for raw materials and the amount of waste going to landfills. |
