The steps for the beneficiation of iron ores differ from ore to ore, depending on the mineralogical phases of the particular iron ore and the nature of the association of the gangue minerals with iron oxide in that ore. The extent to which the beneficiation can be undertaken economically depends both on the amount and the nature of the gangue. The analysis of the phases present in an orebody optimises the mining and process operations (separation, beneficiation, sintering, etc).
X-ray diffraction (XRD) provides qualitative and quantitative information about the main ore phases as well as the gangue mineralogy and the amorphous content present in a sample. In addition, modern quantification methods such as Rietveld refinement allow the calculation of the distribution of elements in solid solutions such the substitution of Fe with Al in goethite or hematite.
The use of high speed detectors has made XRD an important tool for grade and process control. Finger printing of XRD data can facilitate multi-dimensional mapping of ore deposits and drill cores, identifying regions of favourable mineral compositions. Grade control using XRD can be completely automated and controlled remotely.
The two case studies in
this paper demonstrate how XRD and finger printing can be used for grade
control, process optimisation and quality control of a goethitic and a
magnetitic iron ore. The enormous potential of XRD as an inexpensive, reliable
tool, useful in the characterisation of iron ores will be demonstrated.
König, U, 2013. Application of x-ray diffraction to iron
ores – potential implications for grade control and downstream processing, in
Proceedings Iron Ore 2013 , pp 275-280 (The Australasian Institute of Mining and Metallurgy: Melbourne).