Specialized metallurgical processes – compositions for use therei – Processes – Producing or purifying free metal powder or producing or...
Reexamination Certificate
2004-08-31
2009-10-13
King, Roy (Department: 1793)
Specialized metallurgical processes, compositions for use therei
Processes
Producing or purifying free metal powder or producing or...
C423S023000, C423S491000
Reexamination Certificate
active
07601200
ABSTRACT:
A method of efficient separation/purification for obtaining high-purity silver chloride which eliminates the necessity of a pretreatment of a refining intermediate comprising sparingly soluble silver compounds and impurity elements when silver chloride is separated from the refining intermediate and purified to a high degree and which enables the silver chloride to be used as a raw material to give high-purity silver metal without necessitating the pyrometallurgical refining or electro-refining of the silver metal. The method is characterized by comprising: a leaching step in which the refining intermediate is leached with an aqueous sulfite solution to extract silver with the solution to thereby form a silver-containing liquid resulting from the leaching and an insoluble residue; a silver chloride generation step in which the liquid resulting from the leaching is neutralized and acidified to precipitate silver chloride and thereby form the silver chloride and a mother liquor; and a silver chloride purification step in which the silver chloride is oxidized in an acidic aqueous solution by adding an oxidizing agent to dissolve and separate impurity elements and thereby form purified silver chloride and a solution containing the impurity elements.
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Asano Satoshi
Heguri Shinichi
Kasai Masushi
Kurokawa Harumasa
Manabe Yoshiaki
Edwards Angell Palmer & & Dodge LLP
King Roy
Sumitomo Metal & Mining Co., Ltd.
Yang Jie
LandOfFree
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