Determination of sodium sulfide and sulfidity in green liquors and smelt solutions
CA 2230266 C · Owner: Pulp And Paper Research Institute Of Canada · Inventors: Leclerc, Denys F.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A rapid method is provided for the on-line determination of sodium sulfide concentration and/or percent sulfidity in green liquors or smelt solutions used for the production of either kraft or sulfite pulp. The method eliminates manual sampling, and the need for frequent equipment maintenance. The method includes the steps of withdrawing samples of a smelt solution or green liquor from the kraft or sulfite manufacturing process subjecting the samples to , near-infrared spectrophotometry over a predetermined range of wave numbers so as to produce absorbance measurements relative to a reference spectrum of either water or a caustic soda-sodium carbonate solution determining the , …
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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 September 9, 1996 and granted April 23, 2002. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended September 9, 2016.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by September 9, 2018.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
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Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.