TREATMENT METHOD FOR FLYING ASH

PROBLEM TO BE SOLVED: To provide a treatment method for flying ash capable of being easily utilized at low cost in industry, realizing volume-reduction in the safe and stable state and recycling of molten flying ash and suppressing elution of heavy metals into washing water after the flying ash containing the heavy metal is washed with water. SOLUTION: In the treatment method for the flying ash, water containing a mineral acid such as sulfuric acid is added to a water-washed residue obtained by solid/liquid separation after the flying ash containing the heavy metal is washed with water to adjust pH to 3-4, it is reacted at a reaction temperature of 60°C or higher, preferably 80°C or higher for 2 hours or longer, preferably 3 hours or longer to perform leaching and an alkali agent such as lime is added to the obtained leaching liquid to neutralize it to pH 7 or more, pH of washing water is adjusted to 6-11. COPYRIGHT: (C)2006,JPO&NCIPI