The effect of CO(II) on the crystallization kinetics of boric acid in a CMSMPR cooling crystallizer which has been suggested as a probable process for boric acid recovery was investigated with steady-state crystal size distribution.
The results showed that there was no habit modification of boric acid crystals in spite of the presence of Co(II), and distribution coefficients for CO(II), defined as the ratio of the Co(II) concentration in the boric acid crystal to that in the boric acid solution, were found to be less than unity, which indicates the possibility of getting relatively pure boric acid crystals as a final product.
The presence of Co(II) resulted in the reduction of growth rates and the increase of nucleation rates of boric acid compared with the crystallization rates of pure boric acid solution.
Relationships permitting the prediction of nucleation and growth rates at various Co(II) concentration and/or residence time(i.e. flow rate) within this experimental ranges were obtained.
Kinetic relationships in the presence of Co(II) between c-crystallization rates of boric acid and supersaturation, Co(II) concentration, and suspension density were found as follows;
G = 1.626 * $10^{-4} s^{1.726} (C^0_i)^{-0.032}$
$B^o= 2.973 {\ast} 10^9 G^{1.149} (C^0_i)^{0.086} M_T^{1.015}$
