Our special expertise relates to the identification and characterisation of minerals in rocks, ores, soils and processed materials, and accurate methods for quantitative X-ray diffraction analysis (Rietveld Analysis).
Of particular note is the development of methods for detailed characterisation of clay minerals, and our ability to characterise mineral phase evolution under simulated process conditions.
Techniques for mineralogical analysis
Our mineralogical services are based on X-ray powder diffraction (XRD) using techniques largely devised across our laboratories in Adelaide and Melbourne.
Analyses can be made of soils, minerals, rocks, ores, industrial products, and chemicals.
We can also perform a range of additional techniques including X-ray fluorescence (XRF) and various wet chemical methods (e.g., ICP, cation exchange capacity).
We also have strong links with CSIRO colleagues, and more broadly within Australia’s’ innovation network (e.g., Monash University, the University of South Australia, ANSTO and the Australian Synchrotron) with expertise in complementary characterisation techniques, such as
- CT imaging
- X-ray absorption spectroscopy
- scanning electron microscopy
- electron probe microanalysis
- XRF mapping
- Fourier transform infrared analysis
- differential thermal analysis, and
- transmission electron microscopy including lattice imaging.
X-ray Diffraction (XRD)
XRD is generally the fastest and most reliable method used in the identification and quantification of crystalline materials.
The technique utilises the diffraction of X-rays from the unique arrangement of atoms in a crystal structure.
The peak positions and intensities in XRD patterns are dependent on the long-range crystallographic order present in the constituent phase(s) within a specimen.
As such, the peaks can be used to identify what mineral phases are present within a specimen (i.e., each mineral phase has its own fingerprint of peaks), and their abundance.
The technique is particularly useful for materials with grain sizes too small for microscopic identification (e.g., clay minerals, soils minerals, dusts).
Our expert team is experienced in the identification and characterisation of minerals in rocks, ores, soils, and processed materials across a range if contexts including:
- iron ore
- iron ore sinter
- acid mine drainage/acid sulphate soils
- copper and iron sulphides
- gangue mineralogy
- tailings and waste rock
- bauxite and alumina
- clays including:
- smectites (e.g., montmorllonite, saponite, nontronite, hectorite)
- lithium ores and processed materials
- nickel laterites
- coal and petroleum
- ilmenites and reduced rutiles.
Our world-class expertise in quantitative mineralogy by XRD is demonstrated by several high placings (e.g., first in 2010, second in 2020 and 2016) in the Reynolds Cup competition, a biennial global competition for accuracy in quantitative mineral phase analysis by XRD.
Sample size requirements
Typically, for qualitative analysis (i.e., mineral phase identification), amounts of approximately 1 g are sufficient. In some instances, such as well crystalline materials, single grains (~1mg) can be analysed using special low background silicon sample holders.
For bulk quantitative mineral phase analysis, amounts of approximately 5 g are sufficient.
Whole soil analysis, where the clay fraction is to be extracted, requires 15-50 g of the whole sample (depending on the clay percentage).
Clay analysis for a supplied <2µm fraction requires approximately 200mg.
For in situ analysis under simulated process conditions, amounts of approximately 1g are sufficient.
Equipment in our mineralogy laboratories
Our laboratory is equipped with seven diffractometers:
- 2x PANalytical multipurpose diffractometers fitted with Co X-ray tube and specially configured for analysis of clay-containing specimens
- 2x Inel diffractometers fitted with CPS120 detector allowing for rapid collection of a wide 2θ-range and optimised for collection of in situ XRD data to characterise mineral phase evolution under simulated process conditions.
- 3x diffractometers (Bruker D8, PANalytical Empyrean, Rigaku SmartLab) with a wide range of possible configurations for XRD data collection tailored to specific specimens and applications.
The laboratory also has high- and low-temperature diffractometer attachments, and a humidity attachment.
Instrument control and data analysis are achieved through state-of-the-art software (bespoke and commercially available products), and our extensive library of minerals specimens is crucial for our unique clay analysis capability.