Effect of pH Cycling and Zinc Ions on Calcium and Magnesium Carbonate Formation in Saline Fluids at Low Temperature

The formation of dolomite is very challenging in the laboratory under ambient conditions due to kinetic inhibition. goal this study was test impact pH cycling and zinc ions on magnesium-rich carbonates saline fluids at a low temperature. Batch reactor experiments were conducted two series experiments, one without with ions, 43 °C. results after 36 diel cycles indicate reaction product assemblage hydromagnesite, aragonite magnesite minor ions. presence leads decrease acid phase which likely plays role assemblage. Moreover, hydration enthalpy other specific ion effects could be additional factors carbonate. show clear evolution towards increasing incorporation magnesium carbonate cycle number, especially reflecting ripening process that enhanced by cycling. Hence, repeated did not lead more ordered (from protodolomite), but rather 92 mol% MgCO3 cycles, even though geochemical models higher saturation index for than magnesite.