| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for treating an aqueous solution of sodium nitrate capable of preventing a precipitation of a produced salt accompanying a reduction treatment, requiring no particular neutralization treatment, and making separation from a catalyst easy. SOLUTION: The aqueous solution of the sodium nitrate to be treated is charged into a first reaction tank 1 with a palladium-copper colloidal solution added thereto as the catalyst. Formic acid is supplied from a first reducer supplying tank 3. The amount of the formic acid supplied is plenty enough to reduce about a half of the sodium nitrate to be treated. The treated solution is next delivered to a second reaction tank 10, to which hydrazine is supplied from a second reducer supplying tank 11. The amount of the hydrazine supplied is plenty enough to reduce about a half of the remaining sodium nitrate to be treated. The hydrazine may be supplied first and the formic acid later. COPYRIGHT: (C)2008,JPO&INPIT
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