Characterization of a standard bauxite and its deferration products by Mِssbauer spectroscopy

The geochemical standard bauxite BX–N was treated with sodium dithionite to selectively remove iron oxides. Mössbauer spectra of the original sample and that which had been thus deferrated showed minor amounts (about 2% of the original content) of hematite that survived the dithionite treatment to be identical to the hematite of the original bauxite. This indicates the residual hematite to be occluded within other mineral constituents of the bauxite rather than constituting a different, possibly better-crystalline variety that is more resistive to dithionite. The possibility of not merely being able to identify, but also to characterize such minor quantities of hematite, demonstrates the suitability of Mössbauer spectroscopy for the study of subordinate iron-bearing constituents of bauxites and similar mineral products that are impervious to processing.