Clinker compositions

Raw Material Proportions. The three main considerations in proportioning raw materials for cement clinker are the potential compound composition the percentage of Hquid phase at clinkering temperatures and the bumabiUty of the raw mix, ie, the relative ease, in terms of temperature, time, and fuel requirements, of combining the oxides into good quaUty clinker. The ratios of the oxides are related to clinker composition and bumabiUty. For example, as the CaO content of the mix is increased, more C S can be formed, but certain limits cannot be exceeded under normal burning conditions. The lime saturation factor (LSF) is a measure of the amount of CaO that can be combined (20) ... 

Pulverized coal is the most usual fuel, though oil, natural gas and lignite are also used. The contributions of the fuel to the clinker composition must be taken into account, especially with coal or lignite, which produce significant quantities of ash broadly similar in composition to the argillaceous component. The fuels also contribute sulphur. 

For most normal clinker compositions, the major sulphate phase will be aphthitalite with its maximum K/Na ratio of 3.0, with minor amounts of KS or C2KS3 or both only with unusually low values of K/Na in the clinker would one expect NS to be formed. It is only possible to estimate a maximum value for the content of anhydrite, based on the amount of SO3 that is not water soluble this will often be zero, as in the example given above. Anhydrite may, however, be determined by QXDA (Section 4.3.2). Rarely, the amount of water-soluble SO3 is insufficient to balance that of water-soluble alkalis this has been attributed to the presence of traces of alkali carbonates (P2), or of potassium oxide and potassium aluminate (KA) (F4). 

Fig. 2.38 Liquidus curves at 1500°C in the part of the CaO-AljOj-SiO. Fields of CjS and CjA primary crystallization are denoted by dashed lines. Cj clinker composition (reduced to three oxides) and ash A (according to %% ). Alright side scheme of Heilmaim experiment ash-clinker sandwich Christensen N.H., Simonsen, Diffusion in Portland Cement Clinker , J. Am Ceram. Soc. 53, 361 (1970), published by John Wiley Sons Ltd, reproduced with the permission of Wiley Sons...

The clinker composition of the first group is a classic belite Portland cement. However, as it was proved experimentally in the case of raw materials, composed of chalk with high silica ratio, the high strength cements can be produced [130]. 

Chromy (1983), utilizing a 2000-point coimt on 22-mm diameter polished sections of a sieved crushed clinker sample, demonstrated the usefulness of the microscope in determining the mineralogical composition of clinker, the data from which were related mathematically to clinker and raw mix composition, and cement strength. He concluded, "If conversion constants linking the equilibrium clinker composition and strength are determined, it is not necessary to carry out the quantitative phase analyses of the clinker produced. Monitoring the free lime content will suffice."... 

Sylla, H.M., "Influence of Clinker Composition and Clinker Cooling on Cement Properties," Congress, ProcessTechnology of Cement Manufacturing,WeTem Deutscher Zementwerke, 1993, pp. 135-145. 

Chen, Y, and Odler, I. (1992b) The progress of Portland cement hydration effect of clinker composition, in Proceedings 9th ICCC, New Delhi, Vol. 4, pp. 24-30. 

Iron-rich belite fluoro-sulfo-aluminate cement is eharacterized by a higher iron content and the presence of significant amounts of the ferrite phase in the clinker. Its clinker composition may vary in the following range (Feng and Zhu, 1986) ... 

Midgley, H.G. (1980) The relationship between cement clinker composition and strength recovery of hydrating high alumina cement during conversion, in Proceedings 7th ICCC, Paris, Vol. 3, pp. V68-70. 

Traditionally, the clinker composition is calculated from a chemical analysis of the clinker, using the time-honored Bogue equations (Bogue, 1929) and the very empirical relationships ... 

Several attempts have been made to relate the strength of cement paste to the clinker composition. A series of equations was proposed by Blaine, et al., in 19681 1 to predict strength against a number of clinker compositions, ignition loss, insoluble fraction, and air and alkali contents. Other investigators have also proposed equations expressing the relationship between the clinker composition and the 28 day strength.P l... 

Yatnatnura T, Kubota Y, Kaneshige T, Nanba M. Effect of spinel clinker composition on properties of alumina-spinel castable. Taikabutsu 1992 44(7) 404-412. 

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