Granted Patent
Utility
US 5,348,713 · App. 07/929,927
Recovery of metal values from zinc plant residues
Inventors:
Derek E. Kerfoot, Michael J. Collins, Michael E. Chalkley
Patented Case
View Patent ↗
Granted: Sep 20, 1994
Filed: Aug 14, 1992
Inventors
Derek E. Kerfoot
Michael J. Collins
Michael E. Chalkley
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.