Mechanism and estimation of Al(OH)_3 crystal growth

摘要

Precipitation is an important stage of the Bayer process. For simulation of this section, growth-rate estimation of Al(OH)_3 crystals, is vital for the solution of population balance. Various published equations for linear growth rate of Al(OH)_3 are reviewed. In all of these equations, a square exponent was considered for supersaturation terms. In some of the previous works, it was believed that BCF model is the governing mechanism for surface growth of crystals. It is shown that polynuclear model is the most probable mechanism. Also, a modification of the best previous correlation is performed, which results in a considerable improvement of the growth-rate estimation over the available published experimental data.