Calcite recrystallization at equilibrium as influenced by initial growth rate and pH

The mineral calcite was evaluated for recrystallization, a process known to change the location of ions in the mineral lattice without apparent change in mineral chemistry. Calcite lattice reconfiguration is cause for concern because it is a ubiquitous mineral with considerable reactivity that plays an important role in contaminant uptake and possible release. The intrinsic factor, crystal growth, and extrinsic factor, pH, were selected as possible driving forces for calcite recrystallization. Calcite growth experiments were conducted using a dual syringe pump technique. Geochemical analysis revealed calcite growth to be affected by syringe pump rate, a variable that showed no correlation with surface roughness. In order to trace recrystallization of laboratory grown calcite, an ion exchange technique with 45Ca radioisotope and a separate 40Ca stable isotope concentration analysis were used during resuspension batch experiments. There was no evident change in any of the radioisotope tracer experiments, indicating calcite stability. Additionally, 40Ca stable isotope concentration measurements support the same idea of calcite stability and its ability to maintain dynamic equilibrium.M.S.Includes bibliographical reference