Granted Patent
Utility
US 5,344,479 · App. 08/029,513
Upgrading copper sulphide residues containing nickel and arsenic
Inventors:
Derek G. E. Kerfoot, Rein Raudsepp
Patented Case
View Patent ↗
Granted: Sep 6, 1994
Filed: Mar 11, 1993
Inventors
Derek G. E. Kerfoot
Rein Raudsepp
Assignee (at issue)
Sherritt Gordon Limited
This patent predates the USPTO's electronic file wrapper — prosecution documents from this era exist only in the Patent Office's paper records. A certified copy of the file history can be ordered from the USPTO's paper archives.