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Extraction kinetics of cerium(IV) from sulfuric acid medium by the primary amine N1923 using a constant interfacial area cell with laminar flow
Author(s) -
Liu Jianjun,
Wang Yanliang,
Li Deqian
Publication year - 2007
Publication title -
journal of chemical technology and biotechnology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.64
H-Index - 117
eISSN - 1097-4660
pISSN - 0268-2575
DOI - 10.1002/jctb.1768
Subject(s) - extraction (chemistry) , reaction rate constant , chemistry , laminar flow , kinetics , amine gas treating , sulfuric acid , volumetric flow rate , analytical chemistry (journal) , thermodynamics , chromatography , inorganic chemistry , organic chemistry , physics , quantum mechanics
BACKGROUND: Thermodynamic studies on Ce(IV) extraction with primary amine N1923 demonstrate that primary amine N1923 is an excellent extractant for separation of Ce(IV) from Re(III). In order to clarify the mechanism of extraction and to optimize the parameters in practical extraction systems used in the rare earth industry, the extraction kinetics was investigated using a constant interfacial area cell with laminar flow in the present work. RESULTS: The data indicate that the rate constant ( k ao ) becomes constant when stirring speed exceeds 250 rpm. The apparent forward extraction rate is calculated to be 10 −1.70 . The activation energy ( E a ) was calculated to be 20.5 kJ/mol from the slope of log k ao against 1000/ T . The minimum bulk concentration of the extractant necessary to saturate the interface ( C min ) is lower than 10 −5 mol L −1 . CONCLUSION: Studies of interfacial tension and the effects of stirring rate and specific interfacial area on the extraction rate show that the extraction rate is kinetically controlled, and a mass transfer model has been proposed. The rate equation has been obtained as: − d[Ce(IV)]/dt = 10 −1.70 [Ce(IV)] [(RNH 3 ) 2 SO 4 ] 1.376 . The rate‐controlling step has been evaluated from analysis of the experimental results. Copyright © 2007 Society of Chemical Industry