Granted Patent
Utility
US 4,629,556 · App. 06/676,477
Purification of kaolin clay by froth flotation using hydroxamate collectors
Inventors:
Roe-Hoan Yoon, Thomas M. Hilderbrand
Patented Case
View Patent ↗
Granted: Dec 16, 1986
Filed: Nov 29, 1984
Inventors
Roe-Hoan Yoon
Thomas M. Hilderbrand
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.