Theoretically, SCR denitration catalyst has unlimited life, but it’s life limited by various reasons; at the same time, under the collective effect of the economy and market, the catalyst has shorter and shorter life, and a large amount of waste tungsten trioxide denitration catalysts are produced. For the continually produced waste catalysts, the best way to treat is resources renewable (the regeneration frequency can only reach 2~3 times); followed by is recycling to ensure maximum utilization of resources, thus realize the goal of saving resources, protecting the environment; and the worst treatment way is landfill with harmless.

 

The steps of typical recovery processing of waste honeycomb SCR catalyst are as follows:

1. SCR spent catalyst was carried out pretreatment like washing, removing ash, then wet grinding, leaching under high temperature and pressure;

2. Adding hydrochloric acid into the leach solution to adjust pH value and remove impurities;

3. Adding hydrochloric acid into leach residue, calcining after fully react to prepare titanium dioxide or titanium-rich material;

4. Preparation of ammonium paratungstate;

5. Preparation of vanadium pentoxide;

6. wastewater reuse treatment.

 

The main products of this process have properties like high purity and recovery rate, mainly as follows: the content of titanium dioxide in rutile titanium dioxide is up to about 90%, and the recovery rate of titanium dioxide is nearly 90%; the content of tungsten trioxide in ammonium paratungstate can be higher than 99%, the recovery rate of tungsten oxide maybe higher than 80%; the content of vanadium pentoxide can reach to 93%, and the recovery rate is higher than 60%.

 

Also the compound with Na and Cl elements introduced can get recycled, the recycling cost of raw material can be lower.

 

In addition, there is no emission of secondary pollutants, mainly performance as follows: the using of washing ash with high-pressure-water and the washed water reused; crushing, fine grinding and leaching when the material is wet; the side-products can be directly sold; wastewater spray for absorbing calcination exhaust.