There are four processes for recycling waste tungsten trioxide SCR denitration catalyst as following:

1. The waste tungsten trioxide SCR denitration catalyst was crushed and re-added to the new manufacturing process of catalyst. In this process, the amount of recovery catalyst is limited, thus the goal of recycling all the waste catalyst can’t be realized.

2. The material carried out sodium treatment and roasting→precipitate V by ammonium chloride from the leachate→ precipitate tungsten by calcium chloride→ de-integrating the Na₄TiO₄ by sulfuric acid; or sodium treatment and roasting→ precipitate tungsten by calcium chloride→ realize the separation of tungsten and V by forming ammonium paratungstate.

Such technology has the following properties:

(1) The material should be crushed before roasting, and always require the particle size equals to or less than 200μm, otherwise it will cause a serious loss of fly ash and large amounts of carbon dioxide emissions in the calcination process;

(2) The heat cannot get fully used;

(3)The separation step and impurity removal method of waste tungsten trioxide denitration catalyst isn’t well considered, and cause the purity of recovered products limited;

(4) does not form a good cycle of process wastewater reuse.

3. Two times of electrolysis with strong electrolyte solution→ adjust pH with ammonium to precipitate vanadium. The industrial application and energy consumption of this process is unknown; besides, W, Ti and other components cannot be separated for recycling.

4. The pretreatment of removing ash→ alkaline leaching at high temperature and pressure→ removing impurities with magnesium salts→ precipitate tungsten and vanadium with calcium salts→ de-integrating the tungsten, vanadium and calcium salts→ extract vanadium→ prepare the material which is rich in titanium→ wastewater reuse treatment. This is the better treatment processing with purity of the recovered products well controlled; moreover, elements Na and Cl well recycling and the energy get fully used.