Rietveld Quantitative Phase Analysis of OPC Clinkers, Cements and Hydration Products

Abstract

It has been more than twenty years since the excellent volume of Reviews in Mineralogy dedicated to Modern Powder Diffraction was published (Bish and Post 1989). That volume contained a series of key articles ranging from the basic of powder diffraction to sample preparation and synchrotron and neutron powder diffraction. Within that volume, quantitative phase analysis was extensively discussed in a specific chapter (Snyder and Bish 1989). Snyder and Bish (1989) discussed the Reference Intensity Ratio approach (also known as Chung method), the method of standard additions (also known as spiking method) and the full pattern-fitting approach using both the Rietveld method and the observed patterns method. The reader is referred to that volume for the basics of powder diffraction, and to the specific chapter by Snyder and Bish (1989) for the history of quantitative phase analysis from powder diffraction and for a discussion or the early findings. Quantitative phase analysis by X-ray powder diffraction dates back to 1925 (Navias 1925). In this work, the amount of mullite obtained by firing selected clays (and a feldspar) was determined by the direct comparison of the intensities of two diffraction lines of the fired samples with those of pure mullite. The patterns were recorded on photographic negatives after an X-ray exposure of 165 hours (almost a week). Quantitative phase analysis (QPA) from diffraction data can be obtained from a number of methods explained in classical books (Klug and Alexander 1974; Cullity 1978; Snyder and Bish 1989; Zevin and Kimmel 1995; Jenkins and Snyder 1996). However, it is now safe to say that QPA from powder diffraction data is nowadays mainly based on the Rietveld methodology (Rietveld 1969; Hill and Howard 1987; Bish and Howard 1988; Bish and Post 1993; Madsen and Scarlett 2008). Hence, …