Unraveling the Effects of Strontium Incorporation on Barite Growth—In Situ and Ex Situ Observations Using Multiscale Chemical Imaging

Impurity ions influence mineral growth rates through a variety of kinetic and thermodynamic processes that also affect partitioning of the impurity ion between the solid and solution. Here, the effect of an impurity ion, strontium, on Barite (BaSO4) (001) growth rates was studied using a combination of high-resolution in situ microscopy with ex situ chemical imaging techniques. In the presence of strontium, ⟨120⟩ steps roughened and bifurcated. The overall Barite growth rate also decreased with increasing aqueous strontium-to-barium ratio ([Sr]/[Ba]aq) 5, steps with an apparent [010] orientation were expressed and growth in the [010] step direction led to an increase in the overall growth rate of the surface. Strontium became preferentially incorporated into the [010] step direction, rathe...