$Al_2O_3-CaO-Cr_2O_3$ 계 내화물의 고온 안정성

High Temperature Stability for Refractories of the System $Al_2O_3-CaO-Cr_2O_3$

  • 이홍립 (연세대, 공대 요업공학과)
  • 발행 : 1980.01.01

초록

CaO was added to the $MgAlCrO_4$ spinel, a main component of the mag-chro refractroies, by 0, 1, 5 and 10 mol% before sintering at 135$0^{\circ}C$ in air. The X-ray diffraction analysis produced an additional X-ray diffraction pattern of 8CaO.$6Al_2O_3$.$2CrO_3$ besides that of $MgAlCrO_4$. The formation of 8CaO.$6Al_2O_3$.$2CrO_3$ was interpreted as due to the presence of CaO.8CaO.$6Al_2O_3$.$2CrO_3$ was unstable and easily vaporized. It was concluded that formation of the unstable pollutant 8CaO.$6Al_2O_3$.$2CrO_3$ could be prevented in reducing atmospheres. It was found that the basic refractories containing $Al_2 O_3 -CaO-Cr_2 O_3$ system would be more stable and much less toxic in reducing at mospheres than in oxidizing stmosphere.

키워드

참고문헌

  1. Trans. Brit. Ceram. Soc. v.57 no.5 The CaO-MaO-SiO₂-Al₂O₃-Cr₂O₃-Fe₂O₃ System W.F. Ford;W.J. Rees
  2. Kogyo-Kagaku-Zasshi v.66 no.7 A Reaction in the System CaCO₃-Cr₂O₃-Al₂O₃ T. Nishino;K. Moteki
  3. Yogyo-Kyokai-Shi v.73 no.1 The Synthesis and Crystallography of a Group of New Compounds Beloging to the Hauyne Type Structure R. Kondo
  4. Hwahak Konghak v.16 no.5 High Temperature Vaporization of High Melting Point Oxides H.L. Lee;C.E. Kim
  5. Yogyo-Kyokai-Shi v.86 no.3 Vaporization of the System MgO-Al₂O₃-Cr₂O₃ H.L. Lee;T. Sata
  6. Hwahak Konghak High Temperature Vaprization of 8CaO·6Al₂·O₃·2Cr₂O₃ H.L. Lee;C.E. Kim;D.J. Kim
  7. The Chemistry of Cement and Concrete(2nd ed.) F.M. Lea;C.H. Desch
  8. Yogyo-Kyokai-Shi v.85 no.10 Reaction between Alkaline Earth Bearing Double Oxide and Cr₂O₃(Ⅰ) T. Nishino;T. Sakurai
  9. Report of Research Laboratory of Engineering Meterials no.3 High Temperature Vaporization from Multicomponent Oxide Materials in Various Atmospheres T. Sata;T. Sasamoto;H.L. Lee
  10. Mass. Thermochemisry for Steelmaking J.F. Elliot;M. Gleiser
  11. Merall. Trans. v.5 The Thermodynamics of Volatilization of Chromic Oxide: Part 1. The Species CrO₃ and CrO₂OH Y.W. Kim;G.R. Belton
  12. U.S. Bur. Mines Bull. no.542 Contributions to the Data on Theoretical Metallurgy J.P. Coughlin
  13. J. Kor. Ceram. Soc. v.15 no.2 High Temperature Vaporization of the High Melting Point Oxides H.L. Lee