Effect of Solution Stoichiometry on BaSO 4 Crystallization from Turbidity Measurements and Modeling.

The impact of solution stoichiometry on the nucleation and growth of BaSO 4 was studied by measuring solution transmittance and subsequent fitting to a crystallization model. Our results show that a large excess of either Ba 2+ or SO 4 2- ions inhibits both the nucleation and growth of BaSO 4 . However, for a small excess of Ba 2+ , the growth is enhanced. The dependence of nucleation and growth rates on supersaturation and solution stoichiometry was captured by a semiempirical rate model. Hence, the solution stoichiometry is a highly relevant parameter while studying all aspects of BaSO 4 crystallization, and it could be worthwhile to examine other minerals similarly.