Secondary Nucleation Process Research Articles

Secondary nucleation of aluminium trihydroxide in seeded caustic aluminate solutions

Scanning electron microscopy shows that secondary nucleation of aluminium trihydroxide in seeded caustic aluminate solutions of industrial composition is closely associated with the crystal growth process via surface nucleation mechanism. When crystallization is preceded by an induction period, the seed crystals develop and give birth to large numbers of secondary nuclei. The role played by impurities normally present in Bayer process solutions is examined and a qualitative mechanism for the secondary nucleation process discussed. Under certain experimental conditions (high supersaturation, absence of impurities), the initial crop of secondary nuclei can grow dendritically. These dendrites can then break away from crystal surfaces to form an additional crop of secondary nuclei.