The production of activated alumina from aluminum hydroxide based waste

Abstract

Activated alumina is a member of a special alumina group and considered to be more valuable and important than commercial quality alumina. Activated alumina is produced by different methods and generally used as a desiccant, an adsorbent and a catalyst. In the present study, the production of activated alumina from aluminum hydroxide based waste was investigated. This waste was obtained from the Seydisehir Eti Aluminum Works and contained aluminium hydroxide in high ratio. Three different production methods were employed in the experiments: acid activation, heat activation and a combination of both these processes. The variables investigated were particle size range, acid medium (HC1, HNO3, H2SO4), activation temperature and time. The experimental results showed that aluminum hydroxide based waste could be converted to activated alumina effectively by using a combination of acid and heat activation processes. Total specific surface area of the whole sample determines the rate of the reaction for each activation method and thus the particle size must be lower than a critical value which is determined as 0.4 mm in this study. Optimum production conditions are determined as HCl-HNO3 solution mixture for acid activation, 390 degrees C and 1 hour for the heat activation process.