Recovery of dissolved gold by sodium borohydride reduction
CA 2013536 C · Owner: Haque, Kazi E. · Inventors: Haque, Kazi E.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A process is disclosed for the direct recovery of gold from cyanide leach liquor, thiourea leach liquor or Bio-D leach liquor. The process comprises reduction precipitation of the gold from solution by the addition of stabilized alkali metal borohydride preferably, sodium, potassium, lithium or ammonium borohydride at, ambient temperature and pressure. High purity gold is obtained by heating the reduced precipitate to about 1200°C. The barren solution is in a condition such that it can be recycled to the upstream process.
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 March 30, 1990 and granted December 3, 1996. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended March 30, 2010.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by March 30, 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.