WET WASTE GAS DESULFURIZATION METHOD

PURPOSE:To obtain high grade gypsum, by mixing MgSO4-containing waste water and CaCl2-containing waste water to form and separate gypsum ad recoverying water containing Mg(OH)2 and CaCl2 from the separated solution to respectively reutilize Mg(OH)2 and CaCl2. CONSTITUTION:Magnesium sulfate-containing waste water 1 and calcium chloride-containing water 2 are mixed to be introduced into a reaction tank 3 to form gypsum which is, in turn, separated by a filter press while calcium sulfate 8 is added to the separated filtrate 7 to form Mg(OH)2 in a reaction tank 9. The reaction product 10 is separated into magnesium hydroxide 12 and a filtrate by a filter press 11 and Mg(OH)2 is used as the adsorbent in wet desulfurization while the filtrate is sent to a CaCl2-containing water tank 14 and a part 15 of said filtrate is sent to a reverse osmosis unit 16 to obtain conc. CaCl2-containing water 17 which is, in turn, returned to a tank 14 and a part of transmitted water 18 is used in the aqueous Mg(OH)2 slurry in a slurry tank 20.