Quantitative Phase Analysis of Bidi-Koum Bauxites (Guinea)

Frank Feret1, Monique Authier-Martin1 and Istváan Sajó2
1 Alcan International Ltd, Arvida Research and Development Centre, Jonquière, Québec, Canada G7S 4K8
2 Bay Zoltan Institute for Materials Science and Engineering, H-1116 Budapest, Fehervati ut 130, Hungary

Abstract: Fifty-two Bidi-Koum bauxites from Guinea, Africa, of diversified chemical composition were characterized for their mineral composition. First, 14 element oxide concentrations were determined by X-ray fluorescence (XRF) using a fusion sample preparation technique. Loss of Mass (LOM) and organic carbon (OC) concentrations were also determined. The initial X-ray diffraction (XRD) phase quantification was carried out employing XDB software. This software allows for full interpretation of a sample diffractogram and helps generate initial concentrations of identified minerals based on a standardless approach. In the stage that followed, the mass balance procedure on the XDB software helped refine the final phase composition. Then, gibbsitic Al2O3 concentrations obtained by wet chemistry for all samples and kaolinitic SiO2 concentrations obtained for selected samples were compared with the concentrations obtained using the XDB software. Phases that were quantified are: gibbsite, boehmite, kaolinite, wavellite, goethite, hematite, quartz, anatase, rutile and illite. Phase concentrations were obtained for illite from K2O and for wavellite from P2O5 concentrations. The alumina substitution in the goethite lattice was also estimated.

Key Words: Bauxite • Boehmite • Gibbsite • Goethite • Hematite • Quantitative Phase Analysis • Wet Chemistry • X-ray Diffraction • X-ray Fluorescence

Clays and Clay Minerals; June 1997 v. 45; no. 3; p. 418-427; DOI: 10.1346/CCMN.1997.0450311
© 1997, The Clay Minerals Society
Clay Minerals Society (www.clays.org)