Low-carbon footprint cements incorporating high volumes of bauxite residue

The use of large quantities of bauxite residue (BR) to produce two types of low-carbon cement (ferrobelitic and aluminoferrite) was studied in this project. These types of cement are of great interest for the industry because of the lower energy demand and CO2 footprint as well as the higher possible incorporation of by-products, compared to ordinary Portland cement (OPC). To produce the clinkers, BR was combined with limestone, clays and reagent chemicals in order to achieve a suitable raw meal chemistry. The goal was to keep BR addition constant at 50 wt% in all mixtures. The mineralogical phase formation at different burning temperatures was estimatedby means of thermodynamic calculations. Clinkers were produced at different temperatures, 1200, 1250 and 1300 °C, followed by rapid cooling by air. The obtained clinkers were mineralogically quantified by the Rietveld method using X-Ray diffraction analysis. Additionally, microstructural characterisation was performed using SEM-EDS. Hydration kinetics were also studied by isothermal calorimetry. The results show that BR quantities as high as 50 wt% can be used to produce reactive, and environmental friendly cement clinkers.status: publishe

Increasing the Fe2O3/Al2O3 ratio in ordinary Portland cement clinker, aiming to incorporate higher contents of bauxite residue

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Bauxite residue as main raw material in the production of calcium sulfo-ferroaluminate clinker

status: publishe