Method for producing catalyst-grade alumina from aluminum sulphate
CA 2200282 C · Owner: Rendall, John S. · Inventors: Rendall, John S.; Lane, Stephen J.; Ahghar, Massoud
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A method of making activated alumina includes beginning with a leach liquor of potassium and aluminum sulphates that is subjected to a surface-cooled crystallizer with a heat-exchanger input temperature of 160°F and a surface-chilled temperature of 60°F to 80°F. Crystals of aluminum sulphate are precipitated and recrystalized by evaporation in a vacuum and at an elevated temperature. Purified crystals of aluminum sulphate are then dried at 50°-60°C. The dried aluminum sulphate crystals are then dehydrated at 400°-450°C after a rise rate of 10°-20°C per minute to drive off most of the water. A roasting and recalcination step at 900°C-950°C after a rise rate of 10°-20°C per minute is used …
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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 March 18, 1997 and granted December 24, 2002. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended March 18, 2017.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by March 18, 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
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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.