Abstract
After gibbsite was milled for 5 min in a Cr-steel oscillating mill, corundum was obtained by heating the powder for 3 h at 800 °C. We found that iron contamination, produced by the milling process, is essential to attain the transformation at this low temperature and is located at the surface of the gibbsite particles. The knowledge of the oxidation state and location of the contaminant elements, necessary to control the solid-state reactions and/or phase transformations induced by the milling, was realized in this work by a characterization performed by chemical analysis, x-ray photoelectron spectroscopy, Mössbauer spectroscopy, and isoelectric point determination. The iron contamination amounted to about 3% (as Fe2O3) for the sample milled for 60 min. That the iron contamination that occurred mainly on the gibbsite amorphous surface was concluded after a comparison of the isoelectric point determination of the milled samples with that of a mechanical mixture of gibbsite and hematite. X-ray diffraction studies showed that gibbsite looses its crystallinity after the first 5 min of milling.
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.
