THE GROWTH AND DISSOLUTION OF AMMONIUM-PERCHLORATE CRYSTALS IN A FLUIDIZED-BED CRYSTALLIZER

The growth and the dissolution of ammonium perchlorate crystals were s tudied in pure and in sodium chloride containing aqueous solutions, in a fluidized bed crystallizer. The presence of sodium chloride in the solution reduced the growth and the dissolution rates of ammonium perc hlorate crystals. The growth rates were interpreted in terms of supers aturation levels. The orders and rate constants were reported. The eff ectiveness factors were estimated from the growth rate data to evaluat e the relative magnitude of the two resistances in series, diffusion a nd integration. The controlling mechanism is mainly by diffusion for t he crystal growth of ammonium perchlorate in pure aqueous solution. Ho wever, both diffusion and integration steps affect the growth of ammon ium perchlorate crystals in the presence of sodium chloride in solutio n. (C) 1998 Elsevier Science B.V. All rights reserved.