PROCESS FOR RECOVERING MG FROM FLUE GAS DESULFURIZATION WASTE LIQUIDS

摘要

PURPOSE:To recover Mg component precisely, by, after the desulfurization of flue gases with a solution of Mg(OH)2, removing dust in a waste liquid, adding alkali to the waste liquid to neutralize it, and settling Mg(OH)2 in the waste liquid to be separated. CONSTITUTION:Desulfurization waste liquid discharged from a flue gas desulfurization apparatus is passed to a settling tank 11, where dust is precipitated, following which the dedusted waste liquid is led to a neutralization tank 12, where alkali solution of NaOH etc. from a alkali storage tank 13 is added to neutralize the dedusted waste liquid to pH 9-12. At the neutralization tank 12, while the neutralized waste liquid is stirred with an agitator 20, settling condition for Mg(OH)2 is adjusted and the neutralized waste liquid is sent to a settling tank 14 where Mg(OH)2 is settled down and recovered, as Mg component, from the lower part of the settling tank 14, while the supernatant liquid is discharged and the neutralized waste liquid is utilized against as a absorption liquid.