Granted Patent
Utility
US 4,604,369 · App. 06/644,614
Method of beneficiating kaolin clay utilizing ammonium salts
Inventor:
Joseph C. S. Shi
Patented Case
View Patent ↗
Granted: Aug 5, 1986
Filed: Aug 27, 1984
Inventor
Joseph C. S. Shi
Assignee (at issue)
Thiele Kaolin Company
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.