Adição de reciclado de tijolo de óxido de magnésio espinela em concretos refratários

Abstract

The consumption of refractories is strongly linked to the metallurgical industry, particularly in steel companies. After being used by industries, refractories are usually disposed of as waste in industrial landfills. However, studies have already shown that part of the disposed materials has the potential to be recycled, returning to the process as raw material. The recycling of these materials offers benefits to manufacturers, such as reduced dependence on inputs, especially imported ones, in addition to the reduction in carbon emissions. The progressive reduction of CO2 emissions has become a fundamental goal for the industrial sector, including refractory suppliers, where the concept of a circular economy, aiming for a zero-waste cycle and the preservation of natural resources, has been gaining more prominence. It is estimated that each ton of recycled spinel magnesia refractory bricks prevents approximately 1500-1900 kg of CO2 emissions (STRUBEL, 2012; RIBEIRO et al., 2021). This research study addresses the characterization of recycled spinel magnesia and evaluates its incorporation into refractory castable. The results of X-ray fluorescence, X-ray diffraction, and SEM/Microprobe analysis showed that the recycled spinel magnesia sample is predominantly composed of MgO, revealing ceramic compatibility for using this waste as raw material for refractory products. The incorporation of the recycled sample into refractory castables favored the results of physical tests such as linear dimensional variation and thermal shock. On the other hand, it was not possible to obtain a free-flowing castable; further studies are necessary to better understand the interaction between the recycled spinel magnesia and the refractory castable. In general, the results obtained are significant in raising interest in studies aimed at using refractory waste as a raw material source.