Patents by Inventor Rolf-Dieter Fischer

Rolf-Dieter Fischer has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Process for purification of aqueous solutions containing hydrogen sulfide, hydrogen cyanide, and ammonia
    Patent number: 5236557
    Abstract: Aqueous solutions which are contaminated by hydrogen sulfide, hydrogen cyanide, and ammonia are brought to a pH of about 3 or less after their formation and treated with an inert gas in a stripping column to remove the sulfide and cyanide. The pH of the solution is then increased to about 10 or more and the solution is again treated with an inert gas in a second stripping column to remove the ammonia.
    Type: Grant
    Filed: December 18, 1991
    Date of Patent: August 17, 1993
    Assignee: Hoechst Aktiengesellschaft
    Inventors: Thomas Muller, Rolf-Dieter Fischer, Ulrich Gerhardus, Norbert Leder, Klaus Poloszyk, Peter Schneller, Wolfgang Brunke