Usage of low-quality industrial residues for eco-friendly cement production
Calcium sulfoaluminate (CSA) belite cements are of increasing importance due to their lower energy consumption and CO2-emission compared to Portland cements. The aim of a recent study was to find an optimal raw meal composition resulting in a clinker with ye’elimite as main phase. The use of calcium carbonate and the sintering temperature should be minimised.
The industrial residues residual bauxite and residual kaolinite were successfully used for an eco-friendly CSA-belite cement. The optimum raw meal composition range was found to be 38–42% limestone, 10–14% anhydrite, 20% residual kaolinite and 25–32% residual bauxite, leading to ye’elimite and larnite contents of 42–45% and 24–37%, respectively.
Sintering temperature could be reduced
Additionally, the sintering temperature could be reduced from the common 1250–1350 °C to 1200 °C. A statistical experimental planning program has been used as a guidance to minimize the necessary amount of experiments for finding the optimum raw meal composition.
The study has been published in Construction and Building Materials, Volume 208, 30 May 2019.