To control the amounts of eluted environmental regulation target substances, e.g., fluorine, boron, lead and hexavalent chromium, below the environmental quality standards for soil contamination of the soil contamination countermeasures act, which substances are eluted simultaneously from combustion ash discharged by a boiler using coal as the main fuel and also burning RPF and wood waste together, and utilize the combustion ash safely in the soil field.
A method of treating combustion ash comprises adding dilute sulfuric acid to the combustion ash to make fluorine, boron, lead and hexavalent chromium eluted, rinsing the solid/liquid-separated residue to remove dilute sulfuric acid, fluorine and boron remaining in the treated residue and subjecting the residue to air drying, or dehydration, so as to reduce the amount of fluorine eluted from the residue to ≤0.8 mg/L and the amount of the eluted boron to ≤1.0 mg/L, measured by the elution test based on the Ministry of Environment notification No.18, 2003, and also control amounts of all other target elements of the soil contamination countermeasures act below the environmental quality standards for soil contamination.
TANI YUKIO
OKUMURA TAKASHI
INOUE YOSHIORI
KAWAE AYANO
