Secondary nucleation of alumina trihydrate

Literature has revealed limited kinetic data on secondary nucleation of alumina trihydrate in the precipitator of the Bayer Process for alumina production. A batch agitated, isothermal, three litre crystallizer was used in the study. A Coulter-Counter was utilized as the particle sizing equipment. The effects of seed density, supersaturation and temperature on secondary nucleation were investigated. Maximum nucleation rates were found to occur at about 70 C and for any crystallization temperature, the nucleation rate passed through a maximum. The correlated equation for the effective secondary nucleation rate of alumina trihydrate is... [Pg.329]

At a given temperature, the crystal surface area has a bigger contribution to the nucleation rate than AC. The low dependence of the nucleation rate on the concentration driving force implies that the secondary nucleation of alumina trihydrate is removal-limited. [Pg.343]

The activation energy for secondary nucleation of alumina trihydrate was found to be 20,7(X) cal/gmol. [Pg.343]