2012/04/05 by Alexander E. S. Van Driessche, Liane G. Benning, Juan Diego Rodriguez‐Blanco +3 · 2 citations
Materials Science · Environmental Science · #Calcium Carbonate Crystallization and Inhibition #Mine drainage and remediation techniques #Minerals Flotation and Separation Techniques
paper · doi:10.1126/science.1215648
openalex publication_date 2012/04/05 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/23
Calcium sulfate minerals such as gypsum play important roles in natural and industrial processes, but their precipitation mechanisms remain largely unexplored. We used time-resolved sample quenching and high-resolution microscopy to demonstrate that gypsum forms via a three-stage process: (i) homogeneous precipitation of nanocrystalline hemihydrate bassanite below its predicted solubility, (ii) self-assembly of bassanite into elongated aggregates co-oriented along their c axis, and (iii) transformation into dihydrate gypsum. These findings indicate that a stable nanocrystalline precursor phase can form below its bulk solubility and that in the CaSO(4) system, the self-assembly of nanoparticles plays a crucial role. Understanding why bassanite forms prior to gypsum can lead to more efficient anti-scaling strategies for water desalination and may help to explain the persistence of CaSO(4) phases in regions of low water activity on Mars.