Granted Patent
Utility
US 4,871,464 · App. 07/158,740
Method for extracting metal ions
Inventors:
Tsugio Kaneko, Fumiya Ishikawa, Yoshinobu Nishiyama, Toshiharu Shibata
Patented Case
View Patent ↗
Granted: Oct 3, 1989
Filed: Feb 23, 1988
Inventors
Tsugio Kaneko
Fumiya Ishikawa
Yoshinobu Nishiyama
Toshiharu Shibata
Assignee (at issue)
Mitsubishi Chemical Industries, Ltd.
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.