Fixation and stabilization of metals in contaminated materials
CA 2118987 C · Owner: Sevenson Environmental Services, Inc. · Inventors: Pal, Dhiraj; Yost, Karl W.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
The present invention discloses a method of treating lead bearing process materials and lead toxic hazardous wastes The, invention relates to treatment methods employed to chemically convert leachable lead in lead bearing solid and liquid waste materials to a non-leachable form by mixing the material with lime gypsum and/or phosphoric acid. The solid and liquid waste materials include contaminated sludges slurries, soils, wastewaters, spent carbon sand, wire chips, plastic fluff, cracked battery casings, bird and buck shots and tetraethyl lead contaminated organic peat and muck. The present invention discloses a process comprising a single step mixing of one or more treatment additives, and …
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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
- Filed March 14, 1994 and granted May 23, 2000. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended March 14, 2014.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by March 14, 2016.
- 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.