Process for preparing titanium dioxide
CA 2233143 C · Owner: Kemira Pigments Oy · Inventors: Vartiainen, Jaana Liisa
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
The invention relates to a process for preparing a solid sulfate cake usable in the preparation of titanium dioxide in which, process a titaniferous feedstock which contains trivalent iron is reduced thermally in a solid state by means of a reducing gas so that the trivalent iron is reduced to bivalent iron without the formation of metallic iron, whereby a titaniferous material having a low ferric iron content is obtained and this material, is reacted with sulfuric acid to form a solid sulfate cake. The invention also relates to a process for preparing titanium dioxide.
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 March 26, 1998 and granted May 21, 2002. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended March 26, 2018.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by March 26, 2020.
- 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.