Using x-ray

Using x-ray diffraction to solve minerals processing problems

CSIRO Minerals is using in-situ and on-line x-ray diffraction analysis to examine various aspects of minerals processing.

Of Contents

1. The science behsind x-ray diffraction (XRD)
2. Mineralogical changes during pressure acid leaching of nickel laterites
3. Dissolution of bauxites in caustic solutions
4. In-situ x-ray diffraction (XRD) analysis of iron ore sinter phases
5. On-line mineralogy via continuous x-ray diffraction (XRD)
6. Investigation of scale formation on inert anodes using tomographic energy-dispersive diffraction imaging (TEDDI)

The science behind x-ray diffraction (XRD)

CSIRO Min erals is using x-ray diffraction (XRD) to examine various aspects of minerals and materials characterisation and processing. Crystals are solids that form by a regular repeated pattern of molecules connecting together. Most (95 per cent) solid materials are crystalline. This means that they have a regular three-dimensional (3D) distribution (lattice) of atoms. When an x-ray beam hits a set of planes in such a lattice it is diffracted at a particular angle. This produces a peak in the diffraction pattern.

Mineralogical changes during pressure acid leaching of nickel laterites

Researcher aligning a capillary sample for x-ray powder diffraction. In-situ x-ray diffraction (XRD) studies werze used by CSIRO scientists to examine the pressure acid-leaching process used to extract nickel from laterite ores. In-situ XRD replicates the industrial processing conditions and collects data while the process is occurring, that is at elevated temperature and pressure. This avoids potential artefacts from sample extraction and preparation affecting the results. Using this technique, scientists can observe reaction mechanisms and rates as well as transitory intermediate phases.

CSIRO's study determined the reaction mechanisms of the nickel extraction process for different temperatures and acid concentrations. This contributes to the fundamental understanding of the process which is essential for its optimisation.

On-line mineralogy via continuous x-ray diffraction

(XRD) Commercial version of an on-line powder x-ray diffraction (XRD) analyser. CSIRO Minerals worked collaboratively with Fuel and Combustion Technology Ltd to design, build and test an on-line powder x-ray diffraction (XRD) analyser to provide a direct measure of the mineralogy in an industrial processing stream. The data from the on-line XRD can be used for dynamic plant control and product quality control.

The Australian cement industry has incorporated the on-line XRD analyser to accurately measure the composition and mineralogy of finished cement in real time. As well as providing quick and accurate information for the cement industry, on-line XRD analysis has potential uses in other areas including:

• mineral processing
• mineral sands
• slurry streams
• paint and pigments
• detergents and cleaners
• routine quantification of sodium phosphates
• polymers
• pharmaceutical