MIXING TREATMENT METHOD OF COLLECTED ASH OF HEAVY OIL FUEL BURNING BOILER AND EXHAUST GAS DESULFURIZATION WASTE WATER

摘要

PROBLEM TO BE SOLVED: To provide a stably operable treatment method mixing collected ash of exhaust gas of a boiler using heavy oil as fuel and waste water generated from an exhaust gas desulfurizer to recover valuables such as vanadium or unburnt carbon and reducing the vol. of formed sludge. SOLUTION: In a mixing treatment method of collected ash and a waste water from an exhaust gas desulfurizer, collected dust (b) of boiler exhaust gas and waste water (a) from an exhaust gas desulfurizer are mixed and a reducing agent (c) is added to the resulting mixture to reduce pentavalent vanadium to tetravalent vanadium and unburnt carbon (i) is separated while magnesium hydroxide (e) and/or aq. ammonia are added to an unburnt carbon separated soln. (m) to adjust the pH of the soln. (m) to 3-9 to separate a highly conc. vanadium-containing sediment 9 and potassium hydroxide (h) or calcium oxide is further added to the separated soln. (h) to adjust the pH of the soln. to 9-12 and this soln. is distilled to recover aq. ammonia k'.