Granted Patent
Utility
US 4,576,815 · App. 06/541,120
Process for the extraction of metal values and novel metal extractants
Inventor:
Frank Robinson
Patented Case
View Patent ↗
Granted: Mar 18, 1986
Filed: Oct 12, 1983
Inventor
Frank Robinson
Assignee (at issue)
IMPERIAL CHEMICAL INDUSTRIES 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.