Granted Patent
Utility
US 4,696,801 · App. 06/828,748
Process for the extraction of metal values with bisimidazole metal extractants
Inventors:
David P. Devonald, Anthony J. Nelson, Peter M. Quan, David Stewart
Patented Case
View Patent ↗
Granted: Sep 29, 1987
Filed: Feb 12, 1986
Inventors
David P. Devonald
Anthony J. Nelson
Peter M. Quan
David Stewart
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.