To assess the quality of bentonites and their suitability for industrial applications, an accurate determination of the smectite content is required. Up to now, it was not possible to use the standard Rietveld method for quantitative phase analysis of smectite-containing samples because of the turbo-stratum disorder of many natural occurring smectites. In this article, a model is proposed to describe the powder X-ray diffraction patterns of montmorillonite samples measured under room conditions.
