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Dissolution equilibria and kinetics of fluorite and calcite mixtures
Author(s) -
Qi Jian,
Knaebel Kent S.
Publication year - 1989
Publication title -
aiche journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.958
H-Index - 167
eISSN - 1547-5905
pISSN - 0001-1541
DOI - 10.1002/aic.690350808
Subject(s) - dissolution , calcite , mass transfer , mass transfer coefficient , chemistry , diffusion , thermodynamics , impurity , fluorite , ionic bonding , mineralogy , chromatography , ion , physics , organic chemistry
Minerals commonly contain impurities, and their dissolution involves complicated ionic equilibria and multicomponent mass transfer. This paper describes the experiments that were carried out and proposes a mechanism for dissolution behavior of fluorspar containing calcite as a major impurity in both batchwise and continuous packed‐bed systems. The mechanism is based on analysis of coupled equilibria among the soluble species. Of more than eight potentially relevant species, only three ( viz. , F − , HCO 3 − , and Ca 2+ ) are significant. The coupled flux equations for F − and HCO 3 − are written in terms of “main” and “cross” mass transfer coefficients, with the concentration of ca 2+ being accounted for by electroneutrality. Only one main mass transfer coefficient needs to be determined experimentally; and other coefficients can be evaluated from it by means of simple diffusion coefficient ratios, which are determined independently. The Stanton number based on the main mass transfer coefficient is correlated with Reynolds number and the Schmidt number for packed bed dissolution.