Granted Patent
Utility
US 4,678,563 · App. 06/731,713
Modified alcohol frothers for froth flotation of sulfide ore
Inventor:
Robert O. Keys
Patented Case
View Patent ↗
Granted: Jul 7, 1987
Filed: May 7, 1985
Inventor
Robert O. Keys
Assignee (at issue)
Sherex Chemical Co., Inc.
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.