The STUDIA UNIVERSITATIS BABEŞ-BOLYAI issue article summary

The summary of the selected article appears at the bottom of the page. In order to get back to the contents of the issue this article belongs to you have to access the link from the title. In order to see all the articles of the archive which have as author/co-author one of the authors mentioned below, you have to access the link from the author's name.

  
       
         
    STUDIA CHEMIA - Issue no. 2 / 2015  
         
  Article:   INFLUENCE OF GRAIN AND CRYSTALLITE SIZE ON THE GIBBSITE TO BOEHMITE THERMAL TRANSFORMATION.

Authors:  . 		 
       
         
  Abstract:   Thermal decomposition processes of three different samples of hydrated alumina: Bayer precipitated size fractioned, Bayer precipitated ground and fine precipitated, were studied. These were investigated with special regard to evolution of boehmite. The original samples contained 75-85 wt% of gibbsite, while remaining material with gibbsite-like Al2O3-H2O ratio did not show long range order crystallinity. Decomposition reactions were observed by thermal analysis and reaction products were investigated by powder X-ray diffraction. Grain sizes were determined by laser diffraction and morphological changes of grains were observed by scanning electron microscopy. Boehmite formation is influenced mainly by grain and crystallite sizes of starting materials, while degree of crystallinity is of less importance. Transformation of gibbsite to boehmite was most pronounced in the case of coarse grains, nevertheless in fine particles boehmite evolution seemed retarded.

Keywords: gibbsite decomposition, boehmite evolution, nanocrystalline boehmite, Rietveld-refinement
 
         
     
         
         
      Back to previous page