Redox treatment of alunite ore
CA 1066026 A · Owner: National-Southwire Aluminum Company · Inventors: Stephens, Frank M. (Jr.); Thompson, David L.; Stevens, Douglas N.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
This invention relates to a method for recovering aluminum hydroxide from ore containing alunite by roasting the ore to remove the water of hydration leaching the, roasted ore with a weak base to remove potassium and sulfate, extracting the aluminum content with a mixture of sodium hydroxide and potassium hydroxide and, precipitating aluminum hydroxide crystals from the solution. Between the dehydration and leaching steps there are provided the steps of roasting the dehydrated ore prior to leaching in a reducing atmosphere to remove sulfate and then roasting the reduced ore in an oxidizing atmosphere to convert sulfides present after the reduction step to sulfur oxides.
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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
- Granted November 13, 1979. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended November 13, 1996.
- 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.