Preparation of strontium chloride hexahydrate by batch-cooling crystallization: Control of crystal size and morphology

The effects of initial supersaturation, cooling rate, and stirring rate on the morphology of strontium chloride hexahydrate (SrCl26H2O) crystals were investigated by batch-cooling crystallization, providing optimal operating conditions. Uniform needle-like crystals with a length of 1200.50m and a width of 100.92m on average were obtained. The corresponding aspect ratio of length to width was about 11.90. Moreover, the morphological modification of SrCl26H2O crystals using cetyltrimethylammonium chloride (CTAC) was studied. When 20.30 mmol center dot L-1 of CTAC was added, the length and width of crystals were 792.71m and 233.25m, respectively, and the corresponding aspect ratio decreased to 3.40. The shape of SrCl26H2O crystal changed to granule-like, probably because of the strong interaction of CTAC with the SrCl26H2O facets with a denser distribution of Cl- ions. This study offers a simple, flexible, and highly efficient approach to regulate the morphology of SrCl26H2O crystals and opportunities for multiple applications of SrCl26H2O.