Characterization of Barite Suspensions During Synthesis by Light Scattering

Barite concentration changes were made by stepwise addition of barium dichloride to a disodium sulfate solution with intermediate temperature scans while light scattering was measured continuously. Comparing with independent particle size determinations, recorded turbidity changes corresponded well to changes in particle concentration and size. In the absence of dispersing agents, light scattering from stirred BaSO4 suspensions at temperatures >50°C varied in a random fashion, indicating loosely associated particle aggregates. With a dispersant an almost linear relationship between particle concentration and light scattering was established in a wide temperature range. A nonionic surfactant of the alkyl ethoxylate type and a polyacryl amide were compared with respect to their capacity to stabilize BaSO4 suspension turbidities. Correlations observed between particle size and light scattering of the suspension vs temperature and the relative light scattering stabilizing mechanism of dispersants are discussed. It is inferred that essentially monodisperse barite particles may be produced by precipitation in water in the presence of a suitable dispersant. Despite the complexity of the system it was possible, with the new analytical technique, to observe that the nonionic dispersant tested did not significantly affect barite crystal growth, but the polyacryl amide was found to have a pronounced effect on the concentration at which particle formation is first observed as well as on particle size.