Method for decolouring sulphuric acid deriving from acid production processes
CA 2000879 C · Owner: Nilsson, Sten Ake · Inventors: Jonsson, Jan Lennart; Nilsson, Sten Ake
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
The present invention relates to a method for decolouring sulphuric acid produced in accordance with the contact method, comprising one or more absorption circuits. The produced sulphuric acid is decoloured by adding hydrogen peroxide to the system. The method is characterized by adding the hydrogen peroxide to the sulphuric acid in the final absorption circuit and by, maintaining the temperature in this circuit above about 70°C.
Read the whole patent
Listed from its CIPO record in Patent Yard's archive of Canadian patents past their term. Its claims, description and drawings are in the CIPO record and on Google Patents, and the Claude kit works from them.
Why it's free to use
- Filed October 17, 1989 and granted August 27, 1996. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended October 17, 2009.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by October 17, 2011.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Timeline
Timeline From CIPO dates
Sources & verification
Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.