Metal magnesium industry waste for partial replacement of Portland cement

The high demand for concrete has triggered studies on the mitigation of Portland cement production impacts, such as greenhouse gas emissions and energy demands, in addition to enabling cost reduction. Partial replacement of cement with other materials has been employed as an alternative to minimize the damage caused by the cement industry. In this regard, it is necessary to use materials that efficiently replace cement clinker. This study uses waste generated from the production of metallic magnesium as a partial replacement for Portland cement. The substitution is aimed at reducing the amount of clinker used, as its production necessitates high energy consumption and results in emission of large quantities of CO2 into the atmosphere. The tailings were characterized via X-ray fluorescence (XRF), X-ray diffraction (XRD), scanning electron microscopy (SEM), and granulometric analysis. For evaluating the mechanical behavior and porosity, 25% of the cement (by mass) was replaced with tailings, and the resulting composite was molded into cylindrical specimens. After curing for 28 and 91 days, all specimens underwent compression testing. The results of the physical characterization showed that more than 65% of the tailing grain was lesser than 45 μm in size, which contributes to the packaging effect. In terms of the chemical and mineralogical composition, the tailing had high levels of calcium, and the predominant phases could be identified. The compressive strength of the mortar with substitution was higher than 40 MPa. The convergence observed between the results of the different characterization techniques demonstrates the efficiency of using the waste as a supplementary cementitious material. RESUMO: A alta demanda por concreto faz com que estudos sejam desenvolvidos para amenizar os impactos causados pela produção do cimento Portland, como emissões de gases do efeito estufa e demanda energética, além de viabilizar a redução de custos. A utilização de materiais em substituição parcial do cimento vem sendo empregada como alternativa para minimizar os danos causados pela indústria do cimento. Nesse escopo, se faz necessário utilizar materiais que consigam substituir de maneira eficiente o clínquer de cimento. O presente trabalho utilizou o rejeito resultante da produção de magnésio metálico como substituição parcial do cimento Portland. A substituição visa diminuir a quantidade de clínquer utilizada, tendo em vista que sua produção requer um elevado consumo de