There are a large number of valuable metals in the waste SCR denitration catalyst, if directly discarded, it will cause a huge resources waste; furthermore, vanadium pentoxide can cause environmental pollution because of its highly toxic. For reducing environmental pollution caused in denitration catalyst regeneration process, to establish a program for generating material with high content of valuable metals, and its products can be sold directly as a raw material thus to have some commercial value.

 

The detailed description plan is showed as below:

1. Calcining the waste tungsten trioxide denitration catalyst at 800~850 ℃ for 7 ~ 8 hours, for making the material of titanium, tungsten, vanadium, molybdenum oxidized sufficiently, and removing spent catalyst and combustibles volatile at the same time; cooled after released, and then pulverized to 60 mesh or less for inactive using;

2. Leaching out the material with ammonia which has been calcined and ground at 80~90℃ for 7 to 9 hours, until the mass of tungsten trioxide and molybdenum trioxide are all leached out; carrying out filtration to separate the leaching solution containing tungsten along with molybdenum and leach residue containing titanium vanadium;

3. The leachate is first carried out Mo precipitation with ammonium sulfide, taken out filtration after Mo completely precipitated thus to get the molybdenum sulfide which can be sold as raw molybdenum material; besides, the ammonium tungstate is remained in the filtrate solution;

4. Concentrate the filtrate to about 45% of its original volume by evaporation, and then adjust the pH value to 6.2 with nitric acid, while reducing the temperature of the solution to about 15℃at the same time, and incubated for 5 hours to precipitate ammonium paratungstate crystals, then directly packing the APT for selling after washed, and the crystal liquor returns to evaporation process;

5. Leaching out the vanadium in the residue by reduction roasting method, by the way titanium leaves in the leaching residue, thus to separate vanadium and titanium; after cooling down and filtrating, the residue can be sold as the titanium-rich material;

6. Add KClO₃ into the filtrate to precipitate V₂O₅, and it can be sold as vanadium application raw material, and the potassium mother liquor can be used as an agricultural fertilizer.