| 摘要 |
PROBLEM TO BE SOLVED: To provide a ferric inorganic flocculant and a manufacturing method thereof capable of only remaining several ppb (μg/liter) order of a divalent manganese ion in a flocculant separation processing liquid in a water-purification processing. SOLUTION: In the inorganic flocculant using the highly purified ferric salt, a (Mn/Fe) ratio in the inorganic flocculant is 0.0009 or less of four decimal place at a mass ratio. In a manufacturing method of an inorganic flocculant liquid, a (Mn/Fe) concentration ratio of in the inorganic flocculant liquid is reduced by adding an alkalizing agent and an oxidizing agent selected from the group consisting of a permanganate ion, a persulfate ion and a perchlorate ion to an aqueous ferric slat solution containing a manganese ion and removing the manganese ion. In the method and the apparatus for aggregation-processing of raw water, the flocculant liquid is used.
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