Abstract

Dove and Rimstidt (1985) have reported a solubility-product constant for the mineral scorodite that has prompted several questions regarding their investigation. Solubility studies at 25°C can be an excellent source of equilibrium-constant and free-energy data, but only if carefully conceived, planned, and executed. Some of the more important criteria for a successful study include (1) demonstrated reversibility of the reaction (i.e., approaching equilibrium from both undersaturation and supersaturation); (2) variation of one or more critical parameters over a large enough range to test the stoichiometry of the reaction (e.g., vary pH for the solubility of metal hydroxides, or vary CO2 for the solubility of carbonate minerals); (3) identification of the major reactions and minimization of their number by appropriate choice of experimental conditions; (4) proper characterization of the solid phase before and after the experiment to check for purity, including the appearance of secondary phases forming during the experiment; (5) use of solid-liquid separation and analytical procedures appropriate to the investigation; and (6) appropriate choice of models for converting the raw data to thermodynamic functions.

This content is PDF only. Please click on the PDF icon to access.

First Page Preview

First page PDF preview
You do not currently have access to this article.