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

摘要

PROBLEM TO BE SOLVED: To properly control an addition amt. of a reducing agent while enabling economically stable operation in the mixing treatment of the collected ash and desulfurization waste water of a boiler using heaving oil such as orinoco tar as fuel. ;SOLUTION: The collected ash (b) of the exhaust gas from a boiler and the desulfurization waste water (a) of the boiler are mixed and a reducing agent is added so that oxidation-reduction potential becomes 600mV or less to reduce pentavalent vanadium to tetravalent vanadium and magnesium hydroxide and/or aqueous ammonia (i) is added to adjust the pH of the mixture to 3-9 to form a high concn. vanadium-containing pecipitate (g) which is, in turn, separated while calcium hydroxide or calcium oxide is further added to the separated soln. to adjust the pH thereof to 9-12 and this soln. is distilled to recover ammonia.;COPYRIGHT: (C)1998,JPO