Understanding the nucleation and growth mechanisms of barite (BaSO4) is critical for developing techniques to prevent scale formation and to sequester heavy metal elements. Here, we used a classical optical microscopy approach combined with advanced X-ray nanotomography techniques to investigate the role of Sr2+, flow rate, and confinement on the heterogeneous nucleation of barite on glass surfaces. X-ray tomography data revealed the 3D distributions of barite crystals nucleated in Sr-rich and Sr-free solutions, where the addition of Sr2+ ions increased the nuclei density while inhibited the crystal growth. Our preliminary data showed that the flow rate has a significant impact on the morphology of the nucleating barite crystals. Increasing number of crystals exhibiting a rectangular morphology were found at high flow rates under optical and electron microscopy. Preliminary barite nucleation experiments performed in nano porous glass showed significant increase in the nucleation rate compared with that done in glass tubes, indicating pore-scale confinement could play a central role on nucleation kinetics. The combination of both imaging methods provided complimentary data covering different length scales and will further our understanding on the nucleation and growth mechanism of barite and may have implications for nucleation of other materials.

Understanding the nucleation and growth of barite by optical microscopy and X-ray nanotomography

ACS Spring Meeting 2021

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