Sulfuric acid leaching of aluminum from activated coal spoil

Abstract

This article investigated the leaching processes of activated coal spoil (ACS) aimed at recovering aluminum resource into high value‐added products. The effects of particle size, H2SO4 concentration, solid‐to‐liquid ratio, temperature, and stirring speed on aluminum extraction were experimentally studied with a single factor experiment. Based on the single factor experimental results, the response surface method with a Box–Behnken design was used to determine the key operating conditions, where a predictive equation was established to describe quantitatively the relationships of the relative process parameters. Finally, the leaching kinetic data were successfully examined according to the Avrami model and the apparent activation energy (Ea) was calculated as 51.07 kJ/mol for ACS and 72.88 kJ/mol for non‐ACS, which proved the necessity of activation. © 2016 American Institute of Chemical Engineers Environ Prog, 35: 1575–1583, 2016