Appeal No. 2000-0012
Application No. 09/024,413
the examiner, we are confident that it would have been obvious
for one of ordinary skill in the art to employ appellant's dilute
aqueous solution of sulphuric acid and sodium nitrate as the
leaching composition in the method of SU '761. As shown by the
examiner, Abell and Keyes disclose leaching copper from ore by
using a solution of sulphuric acid, while Stetefeldt and Carnahan
discloses the use of an aqueous solution of sulphuric acid and
sodium nitrate to leach copper from its ore. Indeed, Carnahan
teaches that the nitrate is added for the same reason presently
claimed by appellant, i.e., to speed the dissolution of the
copper (see claim 9 on appeal). As for the claimed recitation of
performing the method without producing NOx gases, we agree with
the examiner that one of ordinary skill in the art would have
been motivated to use the catalytic, stoichiometric amounts of
nitrate disclosed by Carnahan for the obvious purpose of
eliminating the generation of noxious gases.
Regarding the claimed step of treating the ore with
concentrated sulphuric acid to agglomerate the fine particles, we
find that the method of SU '761 of treating the crushed ore
having a size less than 6 mm with concentrated sulphuric acid
would necessarily agglomerate the particles before the leaching
step. We also agree with the examiner that it is of no moment
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