| 摘要 |
PURPOSE:To remove mercury with good efficiency without performing exhaustion to the outside of the system, by converting ionic mercury in waste water to metal mercury and vaporizing said metal mercury by vaporizing gas before cooling said vaporizing gas to recover metal mercury while separating and recirculating said gas. CONSTITUTION:Mercury-containing waste water such as alkali washing water of incinerator exhaust gas is introduced into a reductive reaction tank 1 and reducing treatment is performed by using a reducing agent such as hydrazine hydrate to convert the mercury ion in waste water to metal mercury. Next, the waste water is introduced into a vaporization apparatus 2 and vaporizing gas such as air, nitrogen or argon is blown into the waste water to perform gas- liquid contact treatment and metal mercury is allowed to follow the vaporizing gas. Vaporization treatment may be performed according to either one of a batch system and a continuous system. The metal mercury following vaporizing gas is cooled to 0-10 deg.C by a cooler 3 to transfer mercury to the condensate while the condensate is subjected to solid-liquid separation in a solid-liquid separation tank to recover metal mercury. The separated gas is sucked by a blower 5a and again flowed into the vaporization apparatus 2.
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