TREATING METHOD FOR WASTE LIQUID DISCHARGED FROM WET DESULFURIZING PROCESS

摘要

PURPOSE:To recover sulfonates of quinones and a cpd. of a metal having two or more valences both contained in waste liq. from desulfurization of H2S-contg. gas, by extracting the waste liq. with weak-alkaline tertiary amine of high molecular wt., and by simultaneous adsorption with chelate resin. CONSTITUTION:Wet desulfurization waste liq. described above is led to a pH control tank 13, where it is adjusted to a pH 1-2. To the tank 13 is then admitted air 25 so as to decomposed Na2S2O3 in acidic soln. to form SO2, which is returned to Stretford process in order to separate and recover solid S. The filtrate is sent to a stirring tank 1 and is, after stirring and extraction with addn, of tertiary amine soln., delivered to a settling tank 2, where it is divided into a water layer and an extracted layer. A portion of the extracted layer is circulated to the tank 1, and the other portion is fed to a stirring tank 3 for reverse extraction, where anthraquinonedisulfonate is reverse- extracted with addn. of alkali soln. 22. This extracted layer is circulated to the tank 1, and aq. soln. layer is sent to a pH control tank 8 through a desorbed-soln.-mixing tank 6. In the tank 8, the aq. soln. layer is controlled to a pH 2-6 with chelate resin, an adsorbing agent, in order to adsorb and recover the cpd. of the above described metal (e.g., V).