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Effect of iron impurity in zinc sulfide concentrates on the rate of dissolution
Author(s) -
Crundwell Frank K.
Publication year - 1988
Publication title -
aiche journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.958
H-Index - 167
eISSN - 1547-5905
pISSN - 0001-1541
DOI - 10.1002/aic.690340709
Subject(s) - sphalerite , impurity , dissolution , zinc sulfide , chemistry , band gap , sulfide , zinc , electron transfer , inorganic chemistry , semiconductor , analytical chemistry (journal) , pyrite , materials science , mineralogy , condensed matter physics , physics , optoelectronics , organic chemistry , chromatography
The rate of dissolution of sphalerite is shown to be directly proportional to the concentration of substitutional iron impurity in the solid. This is attributed to the formation of a narrow impurity band within the forbidden band gap of the sphalerite. The impurity band is of iron d ‐orbital origin. The transfer of electrons between this d ‐orbital band and the oxidant is energetically more favorable than the transfer of electrons between the valence band and the oxidant. A fundamental model combining the electronic structure of sphalerite and semiconductor electrochemistry is presented. An equation is derived that describes the rate of dissolution as being first order for the concentration of iron in the solid and half‐order for the concentration of the oxidant. This is in agreement with the experimental evidence.