Treatment of wastes
CA 2075794 C · Owner: Worner, Howard K. · Inventors: Worner, Howard K.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Steelworks dusts or sludge is mixed into sewage preferably in the presence of a flocculating agent to provide a rapid separation of a clear effluent and a sludge which is dewatered and dried to form a solid material adapted to entrap harmful materials in the sewage such as heavy metals, pathogens and organic chemicals. The solid material is supplied to a smelt reduction furnace from which molten iron is recovered and a hot gas discharge is provided from which recovery of zinc and other materials may be achieved other waste, material being removed as a slag.
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 11, 1992 and granted May 4, 1999. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended August 11, 2012.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by August 11, 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.