Purification of elemental sulphur
CA 2037051 C · Owner: Makwana, Manher M. · Inventors: Chalkley, Michael Edward; Collins, Michael Joseph; Makwana, Manher M.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A process for removing mercury or other metal impurities from elemental sulphur contaminated therewith includes mixing such elemental sulphur in a molten state with an aqueous sulphide solution or an aqueous solution of sufficiently high pH which reacts with elemental sulphur and forms a sulphide solution to cause extraction of mercury or other metal contaminants from the elemental sulphur into the aqueous sulphide solutions and separating the aqueous sulphide solution containing mercury or other metal contaminants from the molten elemental sulphur to provide an elemental sulphur product substantially free from mercury and other metal contaminants.
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 June 5, 1990 and granted September 22, 1998. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended June 5, 2010.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by June 5, 2012.
- 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.