Kinetics of pyrite oxidation by hydrogen peroxide in phosphoric acid solutions

The kinetics of pyrite oxidation by hydrogen peroxide in phosphoric acid solutions were investigated. The effects of stirring, temperature, and particle size, as well as of the hydrogen peroxide and phosphoric acid concentrations were studied. The effect of phosphate ion addition was also examined....

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Bibliographic Details
Published in:Journal of the Serbian Chemical Society 1999-01, Vol.64 (12), p.753-764
Main Authors: Dimitrijevic, Mile, Antonijevic, Milan, Dimitrijevic, Valentina
Format: Article
Language:English
Subjects:
hydrogen peroxide
oxidation
phosphoric acid
pyrite
reaction kinetics
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Summary:The kinetics of pyrite oxidation by hydrogen peroxide in phosphoric acid solutions were investigated. The effects of stirring, temperature, and particle size, as well as of the hydrogen peroxide and phosphoric acid concentrations were studied. The effect of phosphate ion addition was also examined. The oxidation kinetics was found to follow a shrinking core model, with the surface chemical reaciton as the rate-controlling step. This is in accord with an activation energy of 57 kJ/mol and a linear relationship between the rate constant and the reciprocal of the particle radius. The reaction order with respect to the hydrogen peroxide concentration was found to be equal to unity. Variation of the phosphoric acid concentration had practically no effect on the rate of pyrite oxidation. Addition of the phosphate ion in the relatively low concentration range (0.005.0.1 mol/dm 3) had a highly negative influence on the rate of pyrite oxidation, indicating that this ion has an inhibiting effect on the oxidation of pyrite by hydrogen peroxide. nema
ISSN:0352-5139
1820-7421
DOI:10.2298/JSC9912753D