Granted Patent
Utility
US 5,064,538 · App. 07/603,053
Membrane process for acid recovery
Inventor:
Daniel A. D. Boeteng
Patented Case
View Patent ↗
Granted: Nov 12, 1991
Filed: Oct 25, 1990
Inventor
Daniel A. D. Boeteng
Assignee (at issue)
Cominco, Ltd.
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.