황산알루미늄의 가수분해에 의해 석출된 AlO(OH) 겔의 숙성시간이 판상 α-Al2O3의 결정성장에 미치는 영향 |
최동욱, 박병기, 서정권, 이정민 |
한국화학연구원 화학공정연구센터 |
Effect of Aging Time of AlO(OH) Gel Precipitated by Hydrolysis of Aluminum Sulfate on Crystal Growth of the Flaky α-Al2O3 |
Dong-Uk Choe, Byung-Ki Park, Jeong-Kwon Suh, Jung-Min Lee |
Center of Chemical Process and Engineering, Korea Research Institute of Chemical Technoloyg |
|
|
|
ABSTRACT |
To precipitate the complex gel of flux and aluminum hydroxides gel, aqueous solution of the mixture of $Na_2CO_3;and;Na_2PO_4{cdot}12H_2O$ was added with stirring in aqueous solution of the mixture of $Al_2(SO_4)_3{cdot}14{sim}18H_2O,;Na_2SO_4$, and then the complex gel was aged in $0{sim}30h;at;90^{circ}C$. As aging time passed, the aluminum hydroxides was grown into the acicular AlO(OH) gel. Also, aging time had an effect on physical properties of the AlO(OH) gel and on crystal growth of the flaky ${alpha}-Al_2O_3$ prepared by molten-salt precipitation. In this study, the complex gel was crystallized in temperature range of $400{sim}1,200^{circ}C$ after drying at $110^{circ}C$, and then it was investigated to effect of aging time on precipitation temperature, size, thickness, morphology and particle size distribution of the flaky ${alpha}-Al_2O_3$ crystal. As aging time passed, the flaky a${alpha}-Al_2O_3$ crystal showed a tendency toward an increase in size and thickness as result from an increase in BET surface area and pore volume of the acicular AlO(OH) gel. |
Key words:
Pseudo-boehmite, Flaky ${\alpha}-Al_2O_3$ crystal, Molten-salt, Pearlescent substrate, Filler |
|