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Synthesis of Pure and Porous CaO·Al2O3 Clinker by Burning of Hydrates

수화물 소성에 의한 고순도 다공성 CaO·Al2O3 클링커의 합성

  • Kim, Du-Hyouk (Department of Advanced Materials Engineering, Kyungnam University) ;
  • Song, Tae-Woong (Department of Advanced Materials Engineering, Kyungnam University)
  • 김두혁 (경남대학교 신소재공학과) ;
  • 송태웅 (경남대학교 신소재공학과)
  • Received : 2010.08.24
  • Accepted : 2010.09.14
  • Published : 2010.09.30

Abstract

For the lower-temperature preparation of calcium monoaluminate(CA, C:CaO, A:$Al_2O_3$) clinker which is hard to synthesize purely within its melting point, an equimolar hydrate was obtained and then used as a starting raw material of clinker burning. The hydrate was prepared from a mixture of waste oyster shell and industrial aluminium hydroxide by heating to $1200^{\circ}C$, grinding and mixing with water. The hydrate was composed of amorphous aluminium hydroxide and $C_3AH_6$(H:$H_2O$) formed by resolution-precipitation mechanism of the system C-A-H. By heating the hydrate, nearly pure and porous calcium monoaluminate clinker was formed at $1400^{\circ}C$ which is fairly lower temperature than that of its melting point. The formation of calcium monoaluminate was performed mainly by the reaction between amorphous alumina and $C_{12}A_7$ caused by the decomposition of $C_3AH_6$. The immediate and earlier formation of $C_{12}A_7$ seemed to be accelerated by not only high surface area and instability of the thermally decomposed hydrate but also the catalytic effect of water decomposed from the hydrate. The final calcium monoaluminate clinker was very porous because of the influence of highly porous shape of the thermally decomposed hydrate.

Keywords

References

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