Process for refining crude material for copper or copper alloy
CA 2091677 C · Owner: Yoshida, Eiji · Inventors: Nakamura, Takashi; Arai, Motohiro; Ikeda, Ryukichi
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A process for refining a crude material for copper or copper alloy which contains as impurity elements at least one species of Pb, Ni, Sb, S, Bi, and As in combination with at least one species of Sn, Fe, and Zn which , comprises the sequential steps of (1) melting a crude material for copper or copper alloy (2a) increasing the oxygen concentration in the melt thereby oxidizing Sn, Fe, and Zn into slag (this step is, carried out if the crude material contains as impurity elements at least one species of Sn, Fe and Zn), (2b) adding to the melt at least one species selected from the group consisting of Fe, Fe oxide Mn, and Mn, oxide, thereby causing Pb, Ni Sb, S, Bi, and As in the, melt to …
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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 25, 1992 and granted October 24, 2000. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended March 25, 2012.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by March 25, 2014.
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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.