Aggregation Behaviour of Gibbsite Crystals in Supersaturated Sodium and Potassium Aluminate Liquors

Abstract The aggregation behaviour of colloidal size gibbsite crystals in synthetic supersaturated caustic aluminate liquors has been investigated as a function of solution alkali metal ion type and Al(III) relative supersaturation in crystallization studies. The results indicate that alkali metal ions (Na+ versus K+) and supersaturation play an influential role in the particle aggregation mechanism. The initial particle aggregation rate is linearly dependent upon Al(III) relative supersaturation, and is significantly greater in Na+ rather than in K+ based suspensions. The study demonstrates that the initial orthokinetic aggregation and subsequent cementation both lead to faster agglomeration in sodium than in potassium aluminate liquors