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Quantification Of Pyrrhotiye O2 Consumption By Using Pyrite Oxidation Kinetic Data

Published online by Cambridge University Press:  30 June 2014

I. Rojo ,
F. Clarens ,
J. de Pablo ,
C Domènech ,
L. Duro ,
M. Grivé  and
D. Arcos
I. Rojo*
Affiliation:
Fundació CTM Centre Tecnològic, Plaça de la Ciència 2, 08243 Manresa (E)
F. Clarens
Affiliation:
Fundació CTM Centre Tecnològic, Plaça de la Ciència 2, 08243 Manresa (E)
J. de Pablo
Affiliation:
Fundació CTM Centre Tecnològic, Plaça de la Ciència 2, 08243 Manresa (E)
C Domènech
Affiliation:
Amphos 21 Consulting, S.L. (E)
L. Duro
Affiliation:
Amphos 21 Consulting, S.L. (E)
M. Grivé
Affiliation:
Amphos 21 Consulting, S.L. (E)
D. Arcos
Affiliation:
Amphos 21 Consulting, S.L. (E)
*
*Corresponding author: isabel.rojo@ctm.com.es
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Abstract

Experiments on the dissolution kinetics of natural pyrrhotite (FeS1-x-) and pyrite (FeS2) under imposed redox conditions to evaluate the oxygen uptake capacity of both minerals were carried out at 25°C and 1 bar. Experimental data indicate that in both cases, Fe(II) released from dissolution of these Fe-bearing sulphides is kinetically oxidized to Fe(III) to precipitate as Fe(III)-oxyhydroxides. While the system is pH controlled by the extent of the sulphide oxidation, Eh is controlled by the redox pair Fe2+/Fe(III)-oxyhydroxides. Pyrrhotite dissolution is faster than that of pyrite but generates less acidity. Consequently, the achieved redox value is more reducing. Experimental data show that the oxidation rates of both minerals (in mol·g-1·s-1) are equivalent under the studied conditions. This fact gives a new opportunity to quantify the reductive buffering capacity of pyrrhotite, for which no kinetic rate law has been still established.

Keywords

kineticsoxidationchemical reaction
Type
Articles
Information
MRS Online Proceedings Library (OPL) , Volume 1665: Symposium NW – Scientific Basis for Nuclear Waste Management XXXVII , 2014 , pp. 93 - 101
Copyright
Copyright © Materials Research Society 2014 

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References

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