The influence of clinkering conditions and cooling rate on the phase composition of Belite-Ye’elimite-Ferrite (BYF) clinker

Abstract

BYF cements are a promising alternative to Portland cement due to their lower carbon dioxide (CO2) emissions and reduced energy requirements. BYF clinkers can generally be produced at lower firing temperatures, and their main clinker phases (belite, ye’elimite, and ferrite) have lower lime content and require less energy for their formation. The formation of these phases, their relative proportions, and polymorphism, which determines their reactivity, strongly depend on clinker synthesis parameters. Therefore, assessing the influence of the raw meal composition, burning conditions, and cooling rate on the BYF clinker phase composition is essential. This study was carried out in order to examine the influence of raw materials proportioning, retention time, and cooling rate on the mineralogy and microstructure of the BYF clinker. Raw meals with different contents of sulfate (SO3) were calculated, and laboratory clinkers were produced in a high-temperature electrical furnace. The burning temperature of the clinkers was set at 1350 °C. The influence of retention time at the maximum temperature was investigated starting at 15 min and including 30, 60, and up to 120 min. The effect of different cooling rates on phase composition and polymorphism of main clinker phases was studied. The resulting mineral composition of the clinkers was examined by X-ray powder diffraction (XRD) with Rietveld refinement for quantitative phase analysis. The experimental results of this study indicate that the retention time of 30 min, excess SO3, and rapid cooling with forced air flow were the most beneficial for obtaining the desired clinker phase composition with the most reactive polymorphs of belite and ye’elimite. It was demonstrated that sulfur content and retention time had a greater effect on clinker mineral composition and polymorphism of belite and ye’elimite than the cooling rate. These results emphasize the importance of optimizing the technological parameters of clinker production to achieve the desired clinker composition.