Appeal No. 1997-0448
Application No. 08/327,980
of 5 wt % or naturally floatable gangue minerals in excess of 10 wt %, each based on
the weight of the concentrate, the process comprising the steps of:
A. contacting an aqueous suspension of the concentrate with oxygen under
a partial pressure of between about 75 and 200 psi and at a
temperature of at least about 150 C such that at least about 95% of the
molybdenite is oxidized to form a soluble hydrous molybdic oxide and
insoluble molybdenum trioxide;
B. separating the soluble molybdic oxide from the insoluble
molybdenum trioxide;
C. contacting the insoluble molybdenum trioxide with ammonium
hydroxide to form soluble molybdate values;
D. contracting [sic, contacting] the soluble molybdic oxide with an organic
solvent containing an extractant that is selective for the soluble molybdic
oxide such that a majority of the metal contaminants remain in the
aqueous mixture while a majority of the soluble molybdic oxide is
extracted into the organic solvent;
E. removing the extracted molybdic oxide of step D from the organic
solvent by contacting the organic solvent with an aqueous solution
containing a stripping reagent selective for molybdenum;
F. combining the soluble molybdate values of step C with the extracted
molybdic oxide of step E to form a mixture of soluble molybdenum
values;
G. crystallizing the soluble molybdenum values of step F; and
H. calcining the crystallized molybdenum values of step G to form
molybdenum trioxide.
20. A process for producing molybdenum trioxide of at least technical grade
from molybdenite concentrate containing molybdenite, at least one of copper in excess
of 5 wt % or naturally floatable gangue minerals in excess of 10 wt %, each based on
the weight of the concentrate, the process comprising the steps of:
A. contacting an aqueous suspension of the concentrate with oxygen under
a partial pressure of free oxygen of between 75 and 200 psi and a
temperature of at least about 150 C such that at least about 95% of the
molybdenite is oxidized to form a soluble hydrous molybdic oxide and
insoluble molybdenum trioxide;
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