TREATING METHOD OF SOLUTIONS AFTER WET TYPE EXHAUST SMOKE DESULFURIZATION TREATMENT

摘要

PURPOSE:To enable COD components mainly composed of dithionate to be removed by adding sulfuric acid and heating in treatment of in-system solutions or discharge water in an exhaust smoke desulfurization apparatus using Ca salt or Na as absorbent. CONSTITUTION:In a wet type exhaust smoke desulfurization process using slurry of Ca(OH)2 or aqueous NaOH solution as an absorption solution, sulfuric acid is added to the in-system solution or discharge solution after the desulfurization treatment and the solution is subjected to heat treatment under atmospheric pressure to decompose the COD components mainly composed of dithionate to SO2 and sulfate. Decomposition conditions are desirably sulfuric acid concentrations 0.3 to 0.6mol/l and 1 to 8 hours of heating at 95 deg.C to boiling point.