Exhaust gas treatment manner null of heavy oil fuel kindling

摘要

PROBLEM TO BE SOLVED: To provide a treatment method capable of efficiently treating exhaust gas of a boiler using heavy oil as fuel with a reduced use amt. of chemicals to recover valuables such as high purity V. ;SOLUTION: In a method treating exhaust gas of a boiler by passing the same through a wet exhaust gas desulfurizer separately using a cooling/dust extraction tower and an absorbing tower, unburnt carbon in the ash/waste water slurry (c) discharged from the cooling/dust extraction tower 1 is separated and magnesium hydroxide and/or aq. ammonia are added to the separated soln. (e) to adjust the pH of the soln. to 3-9 to precipitate tetravalent vanadium hydroxide which is, in turn, separated as a highly conc. vanadiumcontaining precipitate. Slaked lime (r) or quick lime is added to the soln. after separation to adjust the pH thereof to 9-12 and this soln. is distilled to recover aq. ammonia (b).;COPYRIGHT: (C)1998,JPO