Granted Patent
Utility
US 4,350,524 · App. 06/264,009
Process for removal of base metal impurities from molten silver with sulfur hexafluoride
Inventors:
John R. Knoepke, David B. George
Patented Case
View Patent ↗
Granted: Sep 21, 1982
Filed: May 15, 1981
Inventors
John R. Knoepke
David B. George
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.