Granted Patent
Utility
US 4,902,491 · App. 07/339,772
Phosphate feed material for phosphorus electric furnaces and production of same
Inventors:
Joseph H. Finley, Lewis L. Hammermeister, Jared S. Sproul
Patented Case
View Patent ↗
Granted: Feb 20, 1990
Filed: Apr 18, 1989
Inventors
Joseph H. Finley
Lewis L. Hammermeister
Jared S. Sproul
Assignee (at issue)
FMC CORPORATION
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.