%0 Journal Article
%A Morales Sánchez-Migallón, Juan
%A Astilleros García-Monge, José Manuel
%A Fernández Díaz, Lurdes
%T A nanoscopic approach to the kinetics of anhydrite (100) surface growth in the range of temperatures between 60 and 120 °C
%D 2012
%@ Online : 1945-3027. Print: 0003-004X
%U https://hdl.handle.net/20.500.14352/42698
%X In situ observations of the growth of the anhydrite (100) surface in contact with supersaturated aqueous solutions under conditions within the stability field of this mineral (60–120 °C) were conducted using a hydrothermal atomic force microscope (HAFM). Advancement rates were measured for [001] steps, the most stable ones on the anhydrite (100) surface. Isothermal data fit well to linear correlations between step advancement rate and supersaturation; the activation energy for step advancement is 73 ± 5 kJ/mol. This is not significantly higher than activation energies reported for the growth of gypsum (60–70 kJ/mol) and does not support that slow dehydration rates of aqueous calcium is responsible for the well-known difficulty to precipitate anhydrite crystals from supersaturated aqueous solutions at temperatures well above the anhydrite-gypsum equilibrium temperature. The role of structural factors that could inhibit the growth of anhydrite is discussed.
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