Process for the treatment of arsenic-containing sludge
CA 2298425 C · Owner: Sugita, Satoru · Inventors: Baba, Hiroshi; Nishida, Morikata; Sugita, Satoru
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
The present invention relates to a process for the treatment of arsenic-containing sludge obtained by adjusting arsenic-containing waste water to a PH of 12 or greater by the addition of a calcium compound and subjecting the waste water to solid-liquid separation, the process comprising the steps of adding a calcium compound to the arsenic-containing sludge slurry obtained by the solid-liquid separation dewatering the, resulting sludge, drying the dewatered sludge and calcining, the dried sludge. According to the present invention arsenic-containing sludge obtained by treating waste water to precipitate arsenic present therein can be calcined to yield a calcined product which involves no …
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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 February 10, 2000 and granted May 13, 2003. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended February 10, 2020.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by February 10, 2022.
- 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
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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.