WET TREATMENT FOR MAKING DIOXIN HARMLESS

摘要

PROBLEM TO BE SOLVED: To make dioxins harmless at a low cost by bringing an aqueous solution acidified with hydrochloric acid and containing an iron compound in the solid state into contact with the dioxins at a specified relatively low temperature. SOLUTION: Fly ash containing dioxins is introduced through a line 11 into a solid-liquid contact apparatus 10 kept at a lower temperature than 100 deg.C and an aqueous solution acidified with hydrochloric acid and containing an iron catalyst is brought into contact with the fly ash containing dioxins to make the dioxins harmless. An aqueous solution acidified with hydrochloric acid for replenishment is introduced through a line 13 into the solid-liquid contact apparatus 10 and an aqueous alkali solution for pH adjustment is optionally introduced through a line 14. Oxygen or an oxygen-containing gas is optionally introduced through a line 102 into the solid-liquid contact apparatus 10 so as to increase the concentration of dissolved oxygen in the aqueous solution.