Analysis of Geological Minerals Using XRD

Table of Contents

Introduction
Instrument
Software and Data Processing
Conclusion

Introduction

X-ray diffraction is generally employed in geology and mining (earth science) labs to characterize the mineralogical composition, whereas XRF is commonly used for the chemical composition. Phase/mineralogical and elemental characterization of geological materials are very important in terms of evaluating their natural resources and their exploration, extraction and beneficiation processes for industrial requirements.

Several analytical methods are used for characterizing the geological materials dependin on the elements of interest, their specific mineralogical phases and concentration ranges. Elemental analysis methods, including XRF, ICP-MS, ICP-OES, are required to provide complete information in terms of minor, major and trace elements.

XRD, Raman, IR and other structural analysis methods are employed to achieve phase and mineralogical composition based on the relative concentrations of minerals of interest and the nature of the materials.

Among these methods that provide complimentary information, X-ray fluorescence and X-ray diffraction (XRF/XRD) are most commonly employed for both quantitative and qualitative analysis.

Instrument

Thermo Scientific™ ARL™ EQUINOX Series represent a portfolio of XRD instruments from simple, easy-to-use bench-top systems for routine analysis to high-performance, more advanced floor-standing, research-grade systems for analytical laboratories.

The Thermo Scientific™ ARL™ EQUINOX 10​0 and Thermo Scientific™ ARL™ EQUINOX 1000 bench-top XRD models utilize different X-ray power sources and provide different levels of performance and convenience. The ARL EQUINOX 100 uses a customized micro-focus tube (50 W for Cu or 15W for Co) which does not require an external water chiller. This same unit can be transported into the field or between laboratories without the need for any special infrastructure.

On the other hand, the ARL EQUINOX 1000 XRD model employs a standard 3.5 kW source requiring chilled water cooling to the tube. It is the only bench-top XRD instrument with standard and high power XRD tubes that ensure optimum performance in terms of sensitivity and resolution. Users can select from either HOPG monochromator (for high intensity) or Ge monochromator (for high resolution) or both in an optional twin monochromator system (SIAM X), which enables the ARL EQUINOX 1000 to provide high performance that is similar to the bigger and higher priced instruments.

Compared to other diffractometers, the ARL EQUINOX 1000 and ARL EQUINOX 100 provide very fast data collection times owing to their unique curved position sensitive detector (CPS) that measures all diffraction peaks at the same time and in real time. Mining or geological samples for XRD measurements are usually powders which are ground to suitable particle size.

Figure 1. Geological sample recorded 10 minutes on ARL EQUINOX 1000 with Graphite monochromator.


N.R.: The largest peaks with red vertical sticks are all Calcite = Limestone. Quartz peak is identified (blue vertical stick).

Figure 2. Overview on Limestone, Dolomite, Gypsum and Quartz impurities.

Software and Data Processing

The ARL EQUINOX XRD Series diffractometers are equipped with a fully integrated data acquisition and processing software and can also interface with third party programs based on the information that needs to be obtained.

Conclusion

The ARL EQUINOX 100 and ARL EQUINOX 1000 XRD models are convenient, fast and high-performance X-ray diffraction instruments ideally suited for mineralogical and geological studies in terms of quantitative and qualitative data. Data can be produced and processed much faster than standard XRD systems due to the simultaneous acquisition of the full 2θ range. This means that a high throughput of samples can be processed in routine analysis and that more XRD measurements can be carried out on the same sample without affecting the analysis times in an investigative laboratory (exploratory).

This information has been sourced, reviewed and adapted from materials provided by Thermo Fisher Scientific - Elemental Analyzers.

For more information on this source, please visit Thermo Fisher Scientific - Elemental Analyzers.

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