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Crystallization of the (Cd,Ca)CO3 solid solution in double diffusion systems: the partitioning behaviour of Cd2+ in calcite at different supersaturation rates

Published online by Cambridge University Press:  05 July 2018

D. Katsikopoulos*
Affiliation:
Departamento de Geología, Universidad de Oviedo, 33005-Oviedo, Spain
Á. Fernandez-Gonzalez
Affiliation:
Departamento de Geología, Universidad de Oviedo, 33005-Oviedo, Spain
M. Prieto
Affiliation:
Departamento de Geología, Universidad de Oviedo, 33005-Oviedo, Spain
*

Abstract

Considering an ideal solid solution, the partitioning of cadmium in calcite was studied at different levels of supersaturation (δ) using counter-diffusion experiments. The effective (non-equilibrium) distribution coefficients of Cd2+ in calcite (DCd), varied between 20 and 100 depending on the initial concentration of reactants and the evolution of supersaturation. A function that relates the DCd with the supersaturation at nucleation was derived: logDCd= —0.40logδ + 2.42. The relationship obtained suggests that in naturalwaters, Cd2+ can be incorporated to a greater degree in calcite when the solid solution-aqueous solutions system is near to equilibrium, which can occur in scenarios where the supersaturation rate and hence the supersaturation level are relatively small.

Type
Research Article
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2008

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