| 摘要 |
PROBLEM TO BE SOLVED: To obtain the subject reducing agent useful for making harmless a waste, a waste liquor, etc., containing hexavalent chromium produced in a chromium smelting plant, a plating plant, etc., by using chaff of a natural organic substance as a raw material. SOLUTION: This reducing agent comprises a chaff pyroligeneous acid recovered from an exhaust gas discharged from chaff during a process for carbonizing the chaff. When the component composition of the chaff pyroligeneous acid is analyzed, it has pH3.3 (at 21.5 deg.C), 1.041 specific gravity (at20 deg.C), 8.1 acid content (CH3 COOH%), 0.60mg/g basic component, 14.6mg/g neutral component, 1.34mg/g carbonyl component, 1.27mg/g organic acid component, 0.43mg/g phenol component, 33.6mg/g ether-soluble component and 17.4mg/g benzene-extracted amount. |
