| 摘要 |
PROBLEM TO BE SOLVED: To solve the problems wherein an aqueous solution of sodium carbodithionate of piperazine easily precipitates crystals when the aqueous solution is formed into a high concentration, although the aqueous solution of the carbodithionate of the piperazine has high heavy metal-immobilizing ability and is excellent heavy metal-treating agent hardly causing harmful gas when treating he heavy metal. SOLUTION: The high-concentration aqueous solution exceeding 25 wt.% at room temperature (25°C) is obtained in the aqueous solution of the sodium piperazine-N, N'-biscarbodithionate containing a dissimilar metal cation, and the precipitation of the crystal is not caused. The molar ratio of the sodium cation to the dissimilar cation is preferably from 99:1 to 80:20, and the dissimilar cation is preferably potassium cation. COPYRIGHT: (C)2011,JPO&INPIT
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