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Expired Canadian patentCanada

Method of making and a slow release composition for abating acid water formation

CA 1330287 C · Owner: The B.F. Goodrich Company · Inventors: Sobek, Andrew A.; Reutern, Eric; Pausch, Jerry B.

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Abstract From the Canadian patent

Various chemolithotrophic bacteria such as Thiobacillus ferrooxidans by direct or indirect mechanisms catalyze the oxidation of metal sulfides and produce acid, i.e. sulfuric acid and soluble metal salts at a much faster rate than chemical oxidation. Elimination of such bacteria would inhibit the formation of the acid. The natural production of such acids is particularly troublesome in mines e.g. coal mines since, acid water is produced which is damaging to the environment. An effective method of abating or eliminating such acid water production is to apply a bactericide such as a biodegradable organic surfactant which at low pH values are bactericides and hence inhibit the bacteria from …

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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

  • Granted June 21, 1994. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended June 21, 2011.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledJanuary 21, 1988
GrantedJune 21, 1994
Term endedJune 21, 2011
Patent numberCA 1330287 C
Classification (IPC)A01N25/32 +1 more

Timeline

Timeline From CIPO dates

19891992199519982001200420072010Application filedJan 21, 1988Patent grantedJune 21, 1994Term endedJune 21, 2011

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Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.