title: Effects of particle size and coating on decomposition of alumina-extracted residue from high-alumina fly ash.
abstract: The effective removal of alkali in the alumina-extracted reside (AER) obtained by extracting alumina from high-alumina fly ash is the premise for realizing the utilization of the silicon component in the fly ash. Sodium was removed from the AER by a decomposition reaction. The effects of the particle size and reactant coating on the decomposition reaction of AER were studied, and the results showed that by decreasing the particle size, the decomposition reaction rate of AER could be enhanced obviously and the Na2O content of the products could be decreased effectively. In addition, the process and mechanism of the decomposition reaction of AER and the reaction kinetics were investigated. The results revealed that the decomposition reaction of AER started from the outer surface of the AER particles. The reaction kinetics corresponded with shrinking unreacted core models. Furthermore, the decomposition reaction rate of AER could be enhanced obviously by decreasing the particle size because the effect of product layer diffusion was weakened when the particle size of AER was decreased.
authors: National Engineering Laboratory for Hydrometallurgy Cleaner Production Technology, Key Laboratory of Green Process and Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, PR China; University of Chinese Academy of Science, Beijing 100049, PR China.
authors: Zehua
authors: Z
authors: Wang
authors: National Engineering Laboratory for Hydrometallurgy Cleaner Production Technology, Key Laboratory of Green Process and Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, PR China. Electronic address: shma@ipe.ac.cn.
authors: Shuhua
authors: S
authors: Ma
authors: National Engineering Laboratory for Hydrometallurgy Cleaner Production Technology, Key Laboratory of Green Process and Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, PR China.
authors: Zhenhua
authors: Z
authors: Tang
authors: National Engineering Laboratory for Hydrometallurgy Cleaner Production Technology, Key Laboratory of Green Process and Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, PR China.
authors: Xiaohui
authors: X
authors: Wang
authors: National Engineering Laboratory for Hydrometallurgy Cleaner Production Technology, Key Laboratory of Green Process and Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, PR China.
authors: Shili
authors: S
authors: Zheng
keywords: Alumina-extracted residue; Coating; Fly ash; NaCaHSiO(4); Particle size