Phosphorites from the Kodjari deposits of Burkina Faso are composite rocks with a fine-grained matrix phase and
dispersed larger grains. Chemical analysis by XRF revealed a CaO content of 35.98 – 41.33 wt% and a P2O5
content of 26.85 – 30.75 wt%. X-ray diffraction patterns show the abundant presence of carbonate-fluorapatite
(Francolite), Hydroxyapatite and Quartz, with the minor phases Wavellite, Maricite and phyllosilicates. The
mineralogical compositions by Quantitative Rietveld Analysis shows the presence of 75.41 – 83.85 wt% of
phosphate phases, with carbonate structural groups in Francolite and Hydroxyapatite, while F ions are in the
Francolite structure. FTIR analyses also validates the identification of mineral phases with the observation of
bands from structural phosphate groups, from carbonate groups and from structural F. This study highlights the
effectiveness of Quantitative Rietveld Analysis in quantifying the mineralogical composition of phosphorites. The
method is suitable for monitoring the exploitation of mineral deposits.

Phosphate Mineralogy X-ray diffraction Rietveld refinement Infra-red spectroscopy