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A Comparison of the Effects of Additives Alumina Nanoparticles and Microparticles on Microstructure and Properties of Magnesia-Doloma Refractory

Shahraki, Aziz | 2015

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 46986 (07)
  4. University: Sharif University of Technology
  5. Department: Materials Science and Engineering
  6. Advisor(s): Nemati, Ali
  7. Abstract:
  8. Magnesia-Doloma refractories has advantages such as stability in alkaline environments, clean steel production, resistance to acid slag, good cement kiln coating flexibility, low production cost. It also has some weaknesses such as low resistance to thermal shock and quick hydration. In the present study using Birjand Mines Magnesite powders and Dolomites from Zefreh, Esfahan, Magnesia-Doloma clinkers were pressed under the pressure 90 MP and prepared at 1650⁰C in furnace under air atmosphere. The effect of adding 0, 2, 4, 6, and 8% of the Microparticles and Nanoparticles of α-Alumina on microstructure, physical properties, hydration resistance and Thermal shock resistance was studied. Phase analysis of samples using X-ray diffraction (XRD) and the microstructure examined by Scanning electron microscope (SEM) was performed. The results show that by adding 6% Wt of Microparticles of α-Alumina and Formed calcium aluminate phase (C3A), physical properties such as bulk density, cold compaction strength (CCS) and Thermal shock resistance improved and samples of hydration resistance declined. Also, with the addition of alumina nanoparticles to 4%Wt Tricalcium aluminate phase (C3A) and to 8% Wt Spinel phase is formed, The results show that Materials containing nanoparticles have better properties than the materials containing microparticles. also create a Spinel phase suitable for chemical and physical properties and high refractory Causes Improve the properties listed. Finally, according to the results obtained and the relationship with the microstructure, %6 Wt of optimal amounts of nanoparticles of α-Alumina as an additive was determined
  9. Keywords:
  10. Alumina ; Refractory ; Refractories ; Thermal Shock Resistance ; Thermal Shock ; Alumina Nanoparticles ; Magnesia-Doloma Refractories ; Hydration Resistance

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