Granted Patent
Utility
US 4,374,713 · App. 06/269,191
Process for separating tungsten from coinage metals
Inventors:
Samuel Natansohn, Gary Czupryna
Patented Case
View Patent ↗
Granted: Feb 22, 1983
Filed: Jun 1, 1981
Inventors
Samuel Natansohn
Gary Czupryna
Assignee (at issue)
GTE Laboratories Incorporated
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.