Granted Patent
Utility
US 4,349,381 · App. 06/192,390
Recovery of heavy metals from spent alumina
Inventor:
Paul Cichy
Patented Case
View Patent ↗
Granted: Sep 14, 1982
Filed: Sep 30, 1980
Inventor
Paul Cichy
Assignee (at issue)
Kennecott Holdings Company
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.