Method for processing zinc silicate-containing zinc crude material
CA 2214611 C · Owner: Ikenobu, Seiji · Inventors: Ikenobu, Seiji; Shimokawa, Kimihiro
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A method for processing a zinc silicate-containing zinc crude material characterized by maintaining a sulfuric acid-acidified solution in the following conditions in extracting zinc from a zinc silicate-containing zinc crude material in a sulfuric acid- acidified leaching tank: liquid temperature (t) : t >= 75°C pH : 1.5 <= pH <= 3.0 Si0 2 concentration : Si0 2 <= 5.0 g/l wherein said Si0 2 concentration is the concentration of ionic silica Si(OH)4 and of colloidal silica (Si0 2)n in said solution.
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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 September 3, 1997 and granted February 18, 2003. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended September 3, 2017.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by September 3, 2019.
- 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.