TREATING METHOD OF RESIDUE OF DESALTING IN COMBUSTION WASTE GAS TREATMENT

摘要

PROBLEM TO BE SOLVED: To treat the residue of desalting so as not to provide the natural environment with a bad affection by a method wherein dioxins in the residue of desalting are decomposed and removed while condensation in a treating system and discharge to the outside of the system are prevented. SOLUTION: When the desalting treatment of combustion waste gas Ga is effected by a waste gas treating means 13, the residue 22 of desalting, which contains dust and harmful heavy metals, is discharged, then, the residue 22 is heated at 400-600 deg.C to decompose and remove dioxins and, thereafter, waster is added to separate non water soluble constituents through solid and liquid separation, then, slag 6, into which the harmful heavy metals do not elute substantially, is obtained by a melting furnace 1. A pH regulating agent 27 is introduced into the water solution 26 of the residue 22a of desalting, which contains remaining water soluble constituents, and solid matter 30 of heavy metals or the like after regulating pH are molten in the melting furnace 1 to obtain the molten slag 6. The supernatant liquid 29 of a settling tank 28 becomes harmless sodium chloride water solution and is discharged. The dioxins in the residue of desalting are heated and decomposed while non water soluble constituents of solid matters in the water solution are slagged and the water solution, from which the non water soluble constituents are separated, is discharged after regulating the pH whereby nature can be protected.