Recovery of thallium from metallurgical flue dusts
CA 2076613 C · Owner: Hancock, Peter J. · Inventors: Hancock, Peter J.; Harris, Cameron L.; Nutten, Robert C.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A process far recovering thallium from pyrometallurgical dust containing lead and thallium comprises smelting the dust in the presence of sodium carbonate and a reductant to produce a thallium containing lead bullion. The quantity of sodium carbonate is in excess of the amount required to react with all the sulphur and chlorine present in the dust to be smelted.
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 August 21, 1992 and granted December 5, 2000. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended August 21, 2012.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by August 21, 2014.
- 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.