Preparation and characterisation of seed for simultaneous removal of sulphur and iron from sodium aluminate solution

Abstract

ABSTRACT This research focuses on the preparation and characterisation of a seed used to remove sulphur and iron simultaneously from sodium aluminate solution. Avrami equation could describe the crystallisation process of sulphur and iron, and their apparent activation energy was calculated. It was found that the Avrami index n of sulphur and iron were between 1.5 and 2, and the crystals grow in one-dimensional acicular and two-dimensional lamellar structures with fine particle size. SEM images displayed that the prepared seed had obvious step morphology, and the growth mechanism was confirmed to be a multilayer spiral growth model. XRD analysis demonstrated that the main components of this seed were Fe2O3, FeS2, NaFeS2·2H2O, Fe(OH)3 and NaFeO2. In the experiment, these components could play the dual role of induced crystallisation and reactive crystallisation, and promote the effective removal of sulphur and iron with little effect on the loss of aluminium.