| 摘要 |
<p>PROBLEM TO BE SOLVED: To efficiently and economically treat a borofluoride, which causes the difficulty of fluorine treatment in a desulfurization waste water treatment system, by adding a water soluble iron compound in the desulfurization waste water in a absorbing solution circulating tank of a dust collecting column to decompose the fluorine compound contained in the desulfurization waste water. SOLUTION: In the desulfurization treatment waste water 11 taken out from the absorbing solution circulation tank of the dust collecting column, a fly ash 20 is separated and removed in a 1st settling vessel 1 and next, sulfuric acid and the iron compound are added to decompose boron fluoride in a decomposing tank 2. Next, in a 1st reaction vessel 3, almost part of Fe ion (3<+> ) is precipitated as ferric hydroxide by adding sodium hydroxide to obtain pH3-5. Next, in a 1st flocculating vessel 4, a high molecular wight flocculant is added to make coarse block, which is separated and recovered as a ferric hydroxide- containing slurry in a 2nd settling vessel 5, and successively aluminum sulfate and NaOH are added in a 2nd reaction vessel 6 and the fluorine component is adsorbed on the deposited aluminum hydroxide.</p> |
