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The relation between particle size and transformation temperature of gibbsite to αLPHA-alumina

Ahmadabadi, M. N ; Sharif University of Technology | 2020

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  1. Type of Document: Article
  2. DOI: 10.1080/25726641.2020.1815504
  3. Publisher: Taylor and Francis Ltd , 2020
  4. Abstract:
  5. The transformation of gibbsite to α-alumina occurs in the range 1100 to 1300°C. The higher the calcination temperature, the larger the crystallites and this leads to abnormal grain growth. The main goal of this research was to reduce the transformation temperature of gibbsite to α-alumina by reducing the gibbsite particles size. The sodium content of the gibbsite used in the study was reduced to less than 0.1% by washing it in HCl solution. It was then ground in a fast mill at ambient conditions for different times then calcined at different temperatures. The microstructure, particles size and thermal behaviour of the samples were examined with SEM, XRD, XRF, PSA and STA, respectively. In a sample ground for 180 min, the transformation temperature decreased from about 1300°C to 1150°C. The reduction in the calcination temperature led to a reduction in α-alumina crystallite size from about 77.16 nm to 64.37 nm. © 2020 Institute of Materials, Minerals and Mining and The AusIMM Published by Taylor & Francis on behalf of the Institute and The AusIMM
  6. Keywords:
  7. Gibbsite ; Grinding ; SEM ; Sodium ; Transformation temperature ; XRD ; α-alumina ; Aluminum oxide ; Calcination ; Chlorine compounds ; Crystallite size ; Grain growth ; Particle size ; Abnormal grain growth ; Alpha alumina ; Ambient conditions ; Calcination temperature ; Gibbsite particles ; Particles sizes ; Thermal behaviours ; Transformation temperatures ; Alumina
  8. Source: Mineral Processing and Extractive Metallurgy: Transactions of the Institute of Mining and Metallurgy ; 2020
  9. URL: https://www.tandfonline.com/doi/abs/10.1080/25726641.2020.1815504?needAccess=true&journalCode=ympm21