Abstract
The bauxite ultrafines studied consists of < 2 μm particles of gibbsite, boehmite, kaolinite, hematite, goethite, anatase and quartz. Electron microscopy and surface analysis (XPS), have shown that iron is present in this material in three forms: separate hematite and goethite particles: extremely small (1–3nm diameter) particles of iron oxide adhering to the surface of gibbsite, boehmite and kaolinite; and lattice-substituted iron in these three minerals. The first and second forms can be removed by mild reductive leaching, without lattice disruption, reducing the total iron oxide content from 5.1 wt.% to 1.7 wt.%. The lower limit of 1.7% is also obtained by extensive leaching with hydrochloric acid and corresponds to the residual lattice-substituted iron. Further discrimination between the cleaned minerals is possible using dispersion, sedimentation, centrifugation and flocculation techniques. For example, an anatase-enriched product or a gibbsite-rich, iron and boehmite depleted product may be obtained. Relevant separation mechanisms are discussed.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
