X-ray Fluorescence Analysis of Complex Materials

dc.contributor.advisor Tickner, James en_US
dc.contributor.advisor Sahajwalla, Veena en_US
dc.contributor.advisor Daniels, John en_US Ganly, Brianna en_US 2022-03-15T08:27:29Z 2022-03-15T08:27:29Z 2018 en_US
dc.description.abstract Portable, in-situ and on-stream X-ray fluorescence (XRF) is widely used in minerals industry applications to analyse materials with little or no sample preparation. These XRF techniques have been found particularly useful for measuring the concentrations of precious and base metal such as gold, platinum, nickel and copper in mineral slurries. The consequence of measuring mineral samples in slurry form is that physical sample effects can limit the accuracy of XRF analysis. This thesis describes two different approaches for improving the XRF analysis of in-situ slurries: thorough characterisation of heavy element L-shell spectra for improved spectral fitting, and the development of a particle size effect correction technique. L-shell X-ray spectra have been measured for 8 elements with atomic numbers between 68 and 79, and the measured line intensity ratios and total subshell intensity ratios are compared to existing theoretical and experimental values. The spectra were carefully fitted to determine line energies and intensities, accounting for Lorentzian line broadening, Compton scattering, incomplete charge collection and the silicon escape effect. A Monte Carlo approach was used to calculate geometry, attenuation and detector efficiency corrections. Up to 15 line intensity ratios and total L1/L3 and L2/L3 subshell intensity ratios are reported for each element. Substantial disagreement is found in both magnitude and trend with atomic number when compared to theory. The measured results are used to predict the errors introduced during elemental composition determination using theoretical basis-function fitting when measured XRF spectra are analysed with incorrect theoretical X-ray emission intensities. The intensity of characteristic fluorescent radiation from mineral phases in particulate materials such as slurries decreases as the particle size of the ore being measured increases. The particle size effect can lead to significant analysis errors, but is usually ignored in on-stream applications where there is limited control over the particle size. This thesis describes measurements of the particle size effect for copper and iron powders in a weakly absorbing matrix. The measured results are compared to a theoretical model and Monte Carlo simulations. A preliminary correction method involving measurements using dual exciting radiation energies is discussed and evaluated using measured and simulated data. en_US
dc.language English
dc.language.iso EN en_US
dc.publisher UNSW, Sydney en_US
dc.rights CC BY-NC-ND 3.0 en_US
dc.rights.uri en_US
dc.subject.other X-ray Fluorescence en_US
dc.subject.other Particle Size Effect en_US
dc.title X-ray Fluorescence Analysis of Complex Materials en_US
dc.type Thesis en_US
dcterms.accessRights open access
dcterms.rightsHolder Ganly, Brianna
dspace.entity.type Publication en_US
unsw.accessRights.uri 2022-05-01 en_US
unsw.description.embargoNote Embargoed until 2022-05-01
unsw.relation.faculty Science
unsw.relation.originalPublicationAffiliation Ganly, Brianna, Materials Science & Engineering, Faculty of Science, UNSW en_US
unsw.relation.originalPublicationAffiliation Tickner, James, CSIRO, Chrysos en_US
unsw.relation.originalPublicationAffiliation Sahajwalla, Veena, Materials Science & Engineering, Faculty of Science, UNSW en_US
unsw.relation.originalPublicationAffiliation Daniels, John, Materials Science & Engineering, Faculty of Science, UNSW en_US School of Materials Science & Engineering *
unsw.thesis.degreetype PhD Doctorate en_US
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