Granted Patent
Utility
US 4,432,868 · App. 06/308,379
Separation of high grade magnetite from fly ash
Inventor:
Robert G. Aldrich
Patented Case
View Patent ↗
Granted: Feb 21, 1984
Filed: Oct 5, 1981
Inventor
Robert G. Aldrich
Assignee (at issue)
Halomet Inc.
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.