A Study on the Preparation of Alumina Powders from Bauxite by Wet Acid Process and Their Utilization(I) : Preparation of Aluminum Hydrate Gels from Bauxite

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J. Korean Ceram. Soc. > Volume 27(6); 1990 > Article

Journal of the Korean Ceramic Society 1990;27(6): 747.

Bauxite로부터 습식 산처리법에 의한 알루미나 분체의 제조 및 그 이용에 관한 연구(I) : Bauxite로부터 Aluminum Hydrate Gel의 제조

박민준, 조철구, 배원태

경상대학교 무기재료공학과

A Study on the Preparation of Alumina Powders from Bauxite by Wet Acid Process and Their Utilization(I) : Preparation of Aluminum Hydrate Gels from Bauxite

ABSTRACT

Aluminum hydrate gels were prepared from the mixtures of bauxite and ammonium sulfate by wet acid process. Optimum conditions for obtaining the maximum yield( 99%) of aluminum hydrates from the same amount of bauxite were confirmed as follows ; 1. Mixing ratio ; addition of 25mole% of ammonium sulfate to 1mole of bauxite. 2. Calcination ; heated at 350℃ for 1hr. 3. Extraction ; leached at 95℃ in 1% H2SO4 for 90min. 4. pH of precipitating solution; slight below 7.0. Amorphous aluminum hydrates were precipitated at the pH lower than 8.5, but the precipitates crystallized to bayerite at the pH was 10. Mean diameter of α-Al2O3 powders which were obtained by calcining the aluminum hydrates was below 0.2㎛, and EDS analysis revealed than SiO2 was it's primary impurity.