The kinetics of desilication of synthetic spent Bayer liquor and sodalite crystal growth

The kinetics of desilication of synthetic, sodium aluminosilicate solution (spent Bayer liquor) and growth of sodalite crystals have been studied unde r isothermal, batch crystallization conditions dose to those prevailing in Bayer process heat exchangers. The desilication rate of the liquor via the formation and growth of sodalite scale on steel substrates was found to be independent of agitation rate. With sodalite seeding, the desilication rate was observed to increase dramatically due to seed crystal growth with the suppression of scale formation. An activation energy of 30 kJ mol(-1) and a second order dependence of the desilication rate on relative supersaturati on of SiO2 were obtained for sodalite crystal growth. (C) 1999 Elsevier Sci ence B.V. All rights reserved.