Preparation of Calcium Sulfate α-Hemihydrate from FGD Gypum in the Autoclave

가압반응기를 이용한 배연탈황석고로부터 α형 반수석고의 생성

  • Park, Seung-Soo (Environment & Chemistry Research Group, Environment Structure Engineering Laboratory Korea Electric Power Research Institute, Korea Electric Power Corporation) ;
  • Kim, Ki-Hyoung (Environment & Chemistry Research Group, Environment Structure Engineering Laboratory Korea Electric Power Research Institute, Korea Electric Power Corporation) ;
  • An, Hi-Soo (Environment & Chemistry Research Group, Environment Structure Engineering Laboratory Korea Electric Power Research Institute, Korea Electric Power Corporation) ;
  • Park, Kwang-Kyu (Environment & Chemistry Research Group, Environment Structure Engineering Laboratory Korea Electric Power Research Institute, Korea Electric Power Corporation)
  • 박승수 (한국전력공사 전력연구원 환경구조연구소 환경화학그룹) ;
  • 김기형 (한국전력공사 전력연구원 환경구조연구소 환경화학그룹) ;
  • 안희수 (한국전력공사 전력연구원 환경구조연구소 환경화학그룹) ;
  • 박광규 (한국전력공사 전력연구원 환경구조연구소 환경화학그룹)
  • Received : 2006.08.17
  • Accepted : 2006.10.12
  • Published : 2006.12.10

Abstract

This study was performed to investigate the formation process of calcium sulfate ${\alpha}$-hemihydrate from FGD gypsum produced at thermal power plant burning bituminous coal. The experimental results showed that calcium sulfate $\alpha$-hemihydrate with a large aspect ratio was produced in the temperature range of $120^{\circ}C$ and $140^{\circ}C$ in the absence of additives through dissolution-recrystallization mechanism. It was also observed that addition of Na-succinate as a catalyst changed crystal shape from acicular to prismatic, resulting in decreased water/powder ratio down to 33%. Optimum concentration of Na-succinate was 20mM. It was confirmed that the optimum moulding pressure and moisture content of moulded body from FGD gypsum were $30kg_f/cm^2$ and between 10% and 15% respectively, which prevent moulded body from collapsing and maximize the capillary effect by given pore volume while autoclaving.

Keywords

FGD;gypsum;${\alpha}$-hemihydrate;moulded body;autoclave

Acknowledgement

Supported by : 산자부

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