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Salting out crystallization of sodium sulfate
Author(s) -
MinaMankarios George,
Pinder Kenneth L.
Publication year - 1991
Publication title -
the canadian journal of chemical engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.404
H-Index - 67
eISSN - 1939-019X
pISSN - 0008-4034
DOI - 10.1002/cjce.5450690138
Subject(s) - chemistry , crystallization , nucleation , supersaturation , sodium sulfate , arrhenius equation , reaction rate constant , sulfuric acid , crystal (programming language) , impurity , salting out , crystal growth , suspension (topology) , analytical chemistry (journal) , sodium , inorganic chemistry , activation energy , crystallography , kinetics , chromatography , aqueous solution , organic chemistry , physics , quantum mechanics , computer science , programming language , mathematics , homotopy , pure mathematics
The growth and nucleation rates of sodium sulfate crystals salted out from their solution in a 38% w/w sulfuric acid solvent by the addition of an 80:20 w/w methanol:water solution, were determined from measurements of the steady‐state crystal size distribution (CSD) generated in a continuous mixed‐suspension, mixed‐product‐removal (MSMPR) salting out crystallizer. The effects of the supersaturation, the crystal suspension density and the temperature on these rates were investigated. The effect of the Cr +++ impurity was also briefly studied. The growth rate kinetic order g was determined to be essentially unity. The nucleation rate kinetic order b was determined as 2.11. The corresponding kinetic rate constants K G and K B were fitted to an Arrhenius type temperature dependence to give. K G = 43960 exp(‐24600 /RT ) and K B = 0.064 exp(70900 /RT ) where R is in kJ/kmol · K. An increase in chromate impurity concentration caused an increase in the growth rate constant K G but had no significant effect on the nucleation kinetics. The kinetiics of crystallization as determined for this system would indicate that a high temperature, high crystal suspension density and long residence time are conditions which are favorable for the production of large sodium sulfate crystals.