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Investigation Effect of Nano- sized Additives on Microstructure and properties of MgO-CaO Refracrories

Ghasemi Kahrizsangi, Salman | 2014

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 47497 (07)
  4. University: Sharif University of Technology
  5. Department: Materials Science and Engineering
  6. Advisor(s): Nemati, Ali
  7. Abstract:
  8. Magnesia–Doloma refractories are considered as a mixed product of alkali products i.e. sintered (fused) magnesia and doloma in which 50-80 wt% magnesia is contained. These refractories enjoy some advantages such as high slag resistance corrosion, high-temperature performance, potential for production of pure molten iron and low cost due to abundance of magnesia and doloma resources in access. However, there exist some problems with these refractories that render them unsuitable for some applications. Among these cases, poor resistance of hydration can be cited that may constrain the amount of this refractory in various industrial applications. In the present work, the addition effect of Fe2O3 and ZrO2 nanoparticles on microstructure and properties of magnesia–doloma refractories. In this case, various contents of Fe2O3 and ZrO2 nanoparticles were separately and together added to magnesia –doloma consisting of 35 wt% CaO. The aim was to take some properties such as bulk density, apparent porosity, cold crush strength, hydration resistance and slag corrosion resistance into consideration. The SEM and XRD analysis were utilized for characterization of phases present in the microstructure. It was shown that addition of nano-Fe2O3 during liquid phase sintering may lead to the formation of low melting point phases such as C2F, C4AF and nano-ZrO2 during solid state sintering and create compounds such as CaZrO3. and reduction free-CaO. These phenomena can result in an increase in bulk density, hydration resistance and a reduction in apparent porosity of magnesia–doloma refractories
  9. Keywords:
  10. Zirconium Oxide ; Refractory ; Hydration Resistance ; Magnesia-Doloma Refractories ; Cold Crush Strength

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