On-line X-ray diffraction far quantitative phase analysis: Application in the Portland cement industry

The aim of this work was to design, construct, install, and commission an o n-line, X-ray diffraction (XRD) analyzer capable of continuously monitoring phase abundances for use in process plant control. This has been achieved through a joint project between CSIRO Minerals and Fuel & Combustion Techno logy Pty. Ltd, with an instrument designed for use in a Portland cement man ufacturing plant. Key factors in tailoring such an instrument to the cement industry were (i) the handling and presentation of a dry sample and (ii) t he development of an analytical method suitable for the complex suite of ph ases contained within Portland cement. The instrument incorporates continuo us flow of sample through the diffractometer using a purpose-built sample p resentation stage. The XRD data are collected simultaneously using a wide r ange (120 degrees 2 theta) position sensitive detector, thus enabling rapid collection of the full diffraction pattern. The data are then analyzed usi ng a Rietveld analysis method to obtain a quantitative estimate of each of the phases present. The instrument is controlled by a PC linked to the diff ractometer through a purpose built interface. The phase abundance informati on is then transmitted to the central computer in the cement plant where it can be used for the control of mill parameters such as temperature and ret ention times as well as gypsum feed rate. (C) 2001 International Centre for Diffraction Data.