Energy Dispersive X-ray Diffraction (EDXRD) is a powerful technique for materials characterisation and for mineralogical composition analysis. However, existing implementations typically rely on synchrotron sources, or large, high-power laboratory and industrial grade instruments. In addition, current EDXRD analysers in industry are generally custom built for individual applications and calibrated for specific samples. The scale and specificity of existing EDXRD analysers make them impractical for exploratory applications, or use in compact, low-power devices.
This work demonstrates the use of a robust and compact, benchtop sized EDXRD analyser for the measurement of powder samples. The analyser is designed for the semi-quantitative analysis of mineral compositions, either as a static measurement or a rolling measurement that can track phase composition as a function of time.
This research explores the fundamental design considerations of a Powder EDXRD (PEDXRD) analyser in terms of the underpinning X-ray physics and how they are influenced by geometrical parameters. To test geometrical parameters, PEDXRD simulations were performed in a custom-modified X-ray tracking toolkit (Geant4) that can simulate powder diffraction. Large volumes of PEDXRD simulations have been completed in Geant4, each with varying geometric variables, leading to the creation of an optimal EDXRD analyser design.
The EDXRD analyser has been constructed and used to measure powder samples in the lab. Multiple samples have been measured, including mixtures of common mineral systems such as calcite and dolomite, iron oxide systems, and powdered steel. PEDXRD spectra are complex as they contain many diffraction peaks, but they also contain X-ray fluorescence (XRF) peaks. To accurately analyse the PEDXRD diffractogram, custom curve fitting software was created. The curve fitting software uses a whole pattern fitting method equipped with custom peak shape parameters to distinctively analyse EDXRD spectra. Using the custom software, semi-quantitative composition data can be extracted from the diffractogram.
In addition, an in-situ cement hydration reaction has been performed to test the analyser’s capability to monitor phase concentrations as a function of time. In a similar test, the analyser has been used to spatially resolve variations in mineral concentrations on a test bed of powder. These tests demonstrate the ability of the analyser to be used in real-world in-situ scenarios and for use in exploratory applications. The quality of the diffractogram from the optimal EDXRD analyser in conjunction with the bespoke curve fitting software combine into a powerful package that opens a range of possibilities for using EDXRD in laboratories and in industry. The compact size of the analyser and the low-power components mean the EDXRD analyser can excel in a range of situations while delivering accurate and fast analysis.
At the time of submission, analyser construction and initial measurements are underway, with preliminary results expected prior to the conference.
For the conference, this presentation will highlight the most important design considerations for EDXRD analysers, as well as showing selected EDXRD diffractograms from different mineral systems. Results of semi-quantitative analysis will be discussed to evaluate the suitability of the analyser for use in industry.