Abstract

Raw materials used in cement manufacturing normally have varying chemical compositions and require regular analyses for plant control purposes. This is achieved by using several analytical instruments, such as XRF and ICP. The values obtained for the major elements Ca, Si, Fe and Al, are used to calculate the plant control parameters Lime Saturation Factor (LSF), Silica Ratio (SR) and Alumina Modulus (AM). These plant control parameters are used to regulate the mixing and blending of various raw meal components and to operate the plant optimally. Any errors and large fluctuations in these plant parameters not only influence the quality of the cement produced, but also have a major effect on the cost of production of cement clinker through their influence on the energy consumption and residence time in the kiln. This paper looks at the role that statistical variances in the analytical measurements of the major elements Ca, Si, Fe and Al can have on the ultimate LSF, SR and AM values calculated from these measurements. The influence of too high and too low values of the LSF, SR and AM on clinker quality and energy consumption is discussed, and acceptable variances in these three parameters, based on plant experiences, are established. The effect of variances in the LSF, SR and AM parameters on the production costs is then analysed, and it is shown that variations of as large as 30% and as little as 5% can potentially occur. The LSF calculation incorporates most chemical elements and therefore is prone to the largest number of variations due to statistical variances in the analytical determinations of the chemical elements. Despite all these variations in LSF values they actually produced the smallest influence on the production cost of the clinker. It is therefore concluded that the LSF value is the most practical parameter for plant control purposes.

Highlights

  • This paper looks at the role that statistical variances in the analytical measurements of the major elements Ca, Si, Fe and Al can have on the ultimate Lime Saturation Factor (LSF), Silica Ratio (SR) and Alumina Modulus (AM) values calculated from these measurements

  • This paper looks at the role that statistical variances in the analytical measurements of the major elements Ca, Si, Fe and Al can have on the ultimate LSF, SR and AM values calculated from these measurements

  • The effect of variances in the LSF, SR and AM parameters on the production costs is analysed, and it is shown that variations of as large as 30% and as little as 5% can potentially occur

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Summary

Anne Love

HERMAN POTGIETER is tans professor en Hoof van die Divisie Chemie en Materiale in die Skool vir Biologie, Chemiese en Gesondheidswetenskappe by die Manchester Metropolitan Universiteit in Engeland. HERMAN POTGIETER is currently professor and Head of the Division of Chemistry and Materials in the School of Biology, Chemistry and Health Sciences at Manchester Metropolitan University in the UK He previously taught Chemistry, Materials Science and Cement/Concrete Technology at the Universities of Pretoria, the Witwatersrand and Pretoria Technikon in South Africa. ANNE LOVE is an associate professor in the School of Mathematics at the University of the Witwatersrand where she teaches several courses on Differential Equations, Calculus, Fourier series, Laplace transforms and methods, Applied complex variables and Differential geometry, mostly to engineering students in various disciplines She is interested in the analysis of experimental data for materials engineering projects, for WC-Co composite materials, an area in which she has published several papers. Suid-Afrikaanse Tydskrif vir Natuurwetenskap en Tegnologie, Jaargang 29 No 2: Junie 2010

EKSPERIMENTELE BENADERING
Element uitgedruk Kleinste statistiese Grootste statistiese
RESULTATE EN BESPREKING
Tipiese waarde
Werklik Afgerond Hoog
Variasie in KVF
Full Text
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