Influence of decomposition parameters on agglomeration process and total soda content in precipitated Al(OH)3

Grain size composition of precipitated Al(OH)(3) is dependent on the mechanism of decomposition process of the caustic solution which determines crystal growth process, agglomeration process and secondary nucleation. Because the literature data shows that the growth rate is very low, the agglomeration process plays an important role in increasing the initial particle size. On the other hand, the agglomeration process enables the inclusion of impurities by the grain boundary of sticking Al(OH)(3) particles, above all, the inclusion of soda Na2O. In this paper we investigate the in fluence of caustic soda concentration Na2O(c), that is the supersaturation of the solution, seed charge and seed grain size on the agglomeration and secondary nucleation processes and total soda content in precipitated Al(OH)(3). The results have shown that the factor which causes the increase of the agglomeration process also causes the increase of total soda content in precipitated AI(OH),. (C) 1999 Elsevier Science B.V. All rights reserved.