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Effect of pH of Aluminum Hydroxides Gel Obtained by Hydrolysis of Al2(SO4)3 Solution on Crystal Growth of α−Al2O3

Al2(SO4)3 용액의 가수분해에 의해 얻어진 Aluminum Hydroxides Gel의 pH가 판상 α−Al2O3의 결정성장에 미치는 영향

  • Choe, Dong-Uk (Department of Chemical Engineering, Chungnam National University) ;
  • Park, Byung-Ki (Energy Materials Research Center, Korea Research Institute of Chemical Technology) ;
  • Han, Myung-Wan (Department of Chemical Engineering, Chungnam National University)
  • 최동욱 (충남대학교 화학공학과) ;
  • 박병기 (한국화학연구원 에너지소재연구센터) ;
  • 한명완 (충남대학교 화학공학과)
  • Published : 2007.10.31

Abstract

To precipitate the complex gels of the pH 6, 7, 8, 9 included in a flux and an aluminum hydroxides gel, an aqueous solution of a mixture of $Na_2CO_3\;and\;Na_2PO_4{\cdot}12H_2O$ was added with stirring in an aqueous solution of a mixture of $Al_2(SO_4){_3}{\cdot}18H_2O,\;Na_2SO_4\;and\;K_2SO_4$, and then the complex gels were aged in 20 h at $90^{\circ}C$. As the hydrolysis pH changed, it had an effect on the physical properties such as the crystal structure, crystal morphology and a phase transition temperature of the AlO(OH) gel, and also on the crystal structure, crystal morphology, particle size and particle size distribution of the ${\alpha}-Al_2O_3$ platelets prepared by molten-salt precipitation. Also, in this study, the complex gels were crystallized at $1,200^{\circ}C$ and thereafter dried at $110^{\circ}C$, and then it was investigated to effect of the hydrolysis pH on the crystal structure, morphology and particle size distribution of the ${\alpha}-Al_2O_3$ platelets crystals using XRD, DTA, SEM and particle size analyzer.

Keywords

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