Optimum conditions for leaching calcined alunite ore in strong NaOH

Abstract

The dissolution of calcined alunite ore in NaOH solution was studied at temperatures ranging between 295-383 K. The effects of ore calcination time and temperature, reaction time and temperature, particle size and solid-liquid ratio were investigated. The experimental results showed that, under optimal leaching conditions, the extraction of aluminum can be over 93%. The rate constant describing this solution process was obtained by using a diffusion through the solid product layer controlled, shrinking core model, which yielded good results. The apparent activation energy for the dissolution equals 18.29 kJmol(-1). (C) 2000 Canadian Institute of Mining and Metallurgy. Published by Elsevier Science Ltd. All rights reserved.