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Kinetics of leaching of tunisian phosphate ore particles in dilute phosphoric acid solutions
Author(s) -
Brahim Faouzi Ben,
Mgaidi Arbi,
Elmaaoui Mohamed
Publication year - 1999
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.5450770123
Subject(s) - phosphoric acid , leaching (pedology) , activation energy , dissolution , mass transfer , chemistry , diffusion , kinetics , phosphate , mineralogy , thermodynamics , nuclear chemistry , analytical chemistry (journal) , inorganic chemistry , geology , chromatography , organic chemistry , physics , soil science , quantum mechanics , soil water
Van der Sluis et al.'s model was used to determine the rate of the partial dissolution of a Tunisian phosphate rock with dilute phosphoric acid (1.5 mass% P 2 O 5 ). When the temperature rises from 25 to 90°C, for a given particle size, the mass‐transfer coefficients, k L °, vary from 3 × 10 −3 to 8 × 10 −3 m ·s −1 . The corresponding diffusion coefficients, D , lies between 6 × 10 −7 and 27 × 10 −7 m 2 ·s −1 . Activation energy is equal to 14 kJ·mol −1 and values of k L °, at 25°C, are in the range of 0.28 × 10 −3 and 4 × 10 −3 m·s −1 when the agitation speed goes from 220 to 1030 rpm, showing that the leaching process is controlled by diffusion rather than by chemical reaction.