A nanoscopic approach to the kinetics of anhydrite (100) surface growth in the range of temperatures between 60 and 120 C

• DOI: 10.2138/am.2012.4083
• Publication Date: 2012-05-01T18:59:07Z
• Authors: J. Morales; J. M. Astilleros; L. Fernandez-Diaz
• Keywords: Anhydrite; Supersaturation; Isothermal process

In situ observations of the growth anhydrite (100) surface in contact with supersaturated aqueous solutions under conditions within stability field this mineral (60-120 °C) were conducted using a hydrothermal atomic force microscope (HAFM). Advancement rates measured for [001] steps, most stable ones on surface. Isothermal data fit well to linear correlations between step advancement rate and supersaturation; activation energy is 73 ± 5 kJ/mol. This not significantly higher than energies reported gypsum (60-70 kJ/mol) does support that slow dehydration calcium responsible well-known difficulty precipitate crystals from at temperatures above anhydrite-gypsum equilibrium temperature. The role structural factors could inhibit discussed.