To provide a method by which a minute amount of a noble metal included in cyanogen-containing waste liquor, in particular plating waste liquor can be effectively recovered, and to provide a method for effectively treating the cyanogen-containing waste liquor.
There is provided the noble metal recovery method which includes: a step in which cyanogen is treated under alkaline condition; and a step in which noble metal oxide obtained by the above treatment is reacted with hydrogen disulfide or a metal sulfide salt under acidic condition, thereby precipitating noble metal sulfide and the precipitated noble metal sulfide is filtered or a step in which the noble metal oxide is reacted with metals such as zinc under acidic condition, thereby precipitating noble metal and the precipitated noble metal is filtered. There is also provided the cyanogen-containing waste liquor treatment method which includes a step in which cyanogen waste liquor is contacted with chlorine gas under heating condition of 60°C or higher in a step in which cyanogen waste liquor is subjected to oxidation treatment under alkaline condition.
TAKAHASHI KOKICHI
FURUWATARI TOMOHIRO
Seiji Ozawa
Yusaku Tokai
Kazuhiro Matsuda
Makoto Horiuchi
Masako Yamauchi
Shohei Fujimoto
Shuichi Sonomoto
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