The aim of this paper is to clarify the influence of the clinker on the amount of . The calculation of the cement phases percentages is based on the research work, Calculation of the Compounds in Portland Cement, published by Bogue in 1929 .The usage of high sulphur fuels, industrial wastes, and tires changes completely the working condition of Bogue because the assumed phase compositions may change. The results prove that increasing the amount of in the low alkali clinker decreases the percentages of due to the high incorporation of alumina in the clinker phases mainly and . The correlation is linear till the clinker reaches the 2%. Over that the influence of the clinker became undetectable. A new calculation method for the determination of the in the high sulphur and low alkali clinker was proposed. 1. Introduction Portland cement is a hydraulic material composed primary of calcium silicates, aluminates, and ferrites. In a rotary kiln, at temperature reaching the 1450 C, clinker nodules are produced from a finely ground, homogenised blend of limestone, shale and iron ore. The nodules are subsequently ground with gypsum, which serves to control setting, to a fine powder to produce finished Portland cement. The composition and texture (crystal size, abundance, and distribution) of clinker phases result from complex interactions of raw feed chemical and mineralogical composition, particle size distribution, feed homogenization, and the heating and cooling regime. In order to simplify these phenomena, Bogue [1] proposed an approach for the development of the clinker phases. The ferric oxide (Fe2O3) reacts with aluminium oxide (Al2O3) and lime (CaO) to form the tetracalcium aluminoferrite (C4AF or Ca4Al2Fe2O10). The remaining aluminium oxide reacts with lime to form the tricalcium aluminate (C3A or Ca3Al2O6). The lime reacts with the silicate oxide (SiO2) to form two calcium silicates phases, the dicalcium silicate (Belite, C2S or Ca2 SiO4) and tricalcium silicate (Alite, C3S or Ca3SiO5). Based on the above approach, Bogue proposed four formulae for the calculation of the clinker phase concentrations. Increasing the amount of the high sulphur fuels and the level of waste valorisation, in the cement kilns, changes completely the working condition of Bogue. The negative influence of sulphate on the percentages of silicate phases (alite and belite) was earlier detected by the XRD but that on the tricalcium aluminate (C3A) is still unclear due to the conclusion contradiction in the reported literature. 2. Influence of Sulphur on Silicate Phases The sulphates
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