Process for the microbial oxidation of sulphidic wastes
CA 2078280 A1 · Owner: Shell Internationale Research Maatschappij B.V. · Inventors: Barnes, Lienel John; Suttie, Andrew Beresford
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Process for treating optionally oxidised sulphidic material containing one or more heavy metals, comprising aerobic microbial oxidation of the optionally oxidised sulphidic material in an aqueous suspension using a sulphur oxidising micro-organism to convert optionally oxidised sulphide into soluble sulphate at a pH such that most of the heavy matals are present in an insoluble form. The sulphidic material is especially sulphidic waste preferably sulphidic slag. The formed sulphats is environmentally less harmful than the sulphide, while the heavy metals compounds are suitable for recovery of the metals using known methods. PS26/T1631FF.DOC
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 September 15, 1992. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended September 15, 2012.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by September 15, 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.