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Pattern Fitting for Quantitative X-Ray Powder Diffraction Analysis of Portland Cement and Clinker.


pdf icon Pattern Fitting for Quantitative X-Ray Powder Diffraction Analysis of Portland Cement and Clinker. (619 K)
Stutzman, P. E.

International Conference on Cement Microscopy, 18th. International Microscopy Association. Proceedings. April 21-25, 1996, Houston, TX, Intl. Cement Microscopy Assoc., Duncanville, TX, Jany, L.; Nisperos, A.; Bayles, J., Editor(s)(s), 18-28 pp, 1996.

Keywords:

portland cement; clinker; phase composition; quantitative analysis; qualitative analysis; whole-pattern fitting; x ray powder diffraction

Abstract:

X-ray powder diffraction is a direct method for qualitative and quantitative phase abundance analysis of fine-grained, crystalline materials. While the application of powder diffraction for qualitative analysis in the cement industry is well established, its use in the determination of phase abundance is not as common. Difficulty in measurement of peak intensity and availability of suitable reference standards have limited the application of x-ray diffraction in quantitative analysis. Whole-pattern fitting offers a means to address these problems by using all diffraction peaks to estimate individual phase pattern intensities. Dataplot, a graphics and data analysis language, facilitates pattern-fitting and quantitative phase abundance analyses by applying multivariate linear least-squares regression based upon experimentally derived x-ray diffraction reference patterns. Phase abundance calculation by the internal standard method uses the pattern scale factors calculated in the fit as intensity values. Precision of replicate analyses by pattern fitting show a distinct improvement over measurement by peak profile fitting. Trials using known mixtures of clinker interstitial phases indicate a very good agreement with the known phase abundance values, and absolute errors, based on the whole cement, of less than 1 percent.