Granted Patent
Utility
US 4,977,837 · App. 07/486,802
Process and apparatus for reducing heavy metal toxicity in fly ash from solid waste incineration
Inventors:
Charles E. Roos, Ronald A. Quarles
Patented Case
View Patent ↗
Granted: Dec 18, 1990
Filed: Feb 27, 1990
Inventors
Charles E. Roos
Ronald A. Quarles
Assignee (at issue)
National Recovery Technologies, LLC
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.