Method for preparing mixed compound catalyst used for catalyzing null-valence mercury in flue-gas to be oxidized

The invention relates to a method for preparing mixed compound catalyst used for catalyzing null-valence mercury in flue-gas to be oxidized. The active component of the catalyst comprises a main catalyzing component, a compound component and a mixed modified component, and the method comprises the steps of: adopting an immersion method to mix precursors of the three components and load the mixture on surface of a carrier; and the preparation process comprises immersion, drying and calcining. The main catalyzing component is one or two of manganic oxides and cobaltic oxides and plays a significant part in catalyzing process; the compound component is one or a plurality of oxides of copper, iron, zirconium and titanium and can be compounded with the main catalyzing component to reinforce the activity of the catalyst; and the mixed modified component is one or a plurality of molybdenum, tungsten and vanadium and can dramatically reinforce the anti-sulfur-dioxide property of the catalyst and enhance the low-temperature catalyzing activity of the catalyst. The catalyst prepared by the method can be applied to the catalyzing and oxidizing of null-valence mercury in coal-fired flue-gas to convert the null-valence mercury in the flue-gas into bivalence mercury which can be easily removed so as to realize the high-effective removal of mercury from flue-gas.