Method for recycling tungsten and vanadium from waste SCR denitration catalyst

A denitrification catalyst and extraction agent technology, which is applied in the field of catalyst recovery, can solve the problems of toxic gas pollution, release of toxic gas, and secondary pollution of the environment, and achieve the effects of strong operability, efficient recovery, and low environmental pollution

Inactive Publication Date: 2018-02-16
BEIJING UNIV OF TECH
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Problems solved by technology

Typical ones are: Patent CN201410534406.8 discloses a method for recovering tungsten, vanadium, and titanium in spent SCR denitration catalysts, wherein metal vanadium and tungsten are leached by grinding the catalyst into a powder with a particle size of less than 150 μm, and mixing it with carbonic acid The sodium powder is stirred evenly, then roasted at high temperature, and then the roasted product is placed in hot water for vanadium and tungsten leaching; the method in the patent CN201010254247 roasts the catalyst twice, and then uses hot water to extract vanadium and tungsten. The leaching, tungsten and vanadium leaching rate is less than 90% and other insufficient characteristics
[0004] Patent CN105274341 uses a comprehensive method of roasting and leaching for spent SCR

Method used

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  • Method for recycling tungsten and vanadium from waste SCR denitration catalyst

Examples

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Example Embodiment

[0025] Example 1:

[0026] 1) Leaching of W and V

[0027] Take the waste SCR denitration catalyst (the main component is V 2 O 5 -WO 3 / TiO 2 , the specific components are shown in Table 1), purge the deactivated SCR denitration catalyst with clean and dry compressed air to remove the fly ash deposited on the surface of the catalyst, grind it into powder in the grinding body, and then sieve it with a 100-mesh standard sieve, The catalyst was then dried at 85°C for 6h.

[0028] Table 1: Elemental composition table of spent SCR catalyst

[0029]

[0030] Using sodium hydroxide solution with a concentration of 8%, 5 g of the dried and cooled catalyst powder was leached. The mixed solution was placed in a high-pressure reactor and stirred at a rotational speed of 300 r / min, and the mixed leaching slurry was obtained after leaching.

[0031] Then, the mixed solution was suction filtered. The pore size of the filter membrane was 0.45 μm during the suction filtration proce...

Example Embodiment

[0038] Example 2

[0039] 1) Leaching of W and V

[0040] Using the sodium hydroxide solution that the concentration is 8%, the powder 5g of the catalyst (same as Example 1) after drying and cooling is leached, and the leaching process adopts the mode of high pressure leaching, and the mixed solution is placed in the autoclave and rotates at the rotating speed. Stir at 400r / min, control the liquid-solid ratio to be 10:1, the leaching temperature to be 190℃, and the leaching time to be 3h. The mixed solution was then suction filtered. The pore size of the filter membrane was 0.45 μm in the suction filtration process to obtain the leaching solution containing V and W and set the volume to 100 ml. The calculated leaching rates of W and V were 97.46% and 88.6%, respectively.

[0041] 2) Extraction and purification of W and V in the leachate

[0042] Adjust the pH of the leachate obtained in step (2) to 5.5 with hydrochloric acid;

[0043] Get 30ml of the above-mentioned leachat...

Example Embodiment

[0048] Example 3

[0049] 1) Leaching of W and V

[0050] Using the sodium hydroxide solution that the concentration is 8%, the catalyst (with embodiment 1) powder 5g after drying and cooling is leached, and the leaching process adopts the mode of high-pressure leaching, and the mixed solution is placed in the autoclave and rotates 500r / Min stirring, the liquid-solid ratio is controlled to be 10:1, the leaching temperature is 250°C, and the leaching time is 6h. Then, the mixed solution was suction filtered. During the suction filtration process, the pore size of the filter membrane was 0.45 μm, and the leaching solution containing V and W was obtained and the volume was fixed to 100 ml.

[0051] 2) Extraction and purification of W and V in the leachate

[0052] Adjust the pH of the obtained leachate to 5.5 with hydrochloric acid;

[0053] Get 30ml of the above-mentioned leachate in a separatory funnel, add a solution diluted with primary amine N1923+kerosene, control the v...

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Abstract

The invention provides a method for recycling tungsten and vanadium from a waste SCR denitration catalyst. The method includes the steps that firstly, tungsten and vanadium are leached out, wherein the waste SCR denitration catalyst is placed into a NaOH solution to be leached out, and by means of solid and liquid separation, alkaline leaching liquid containing tungsten and vanadium and residues TiO2 are obtained; secondly, tungsten and vanadium in the alkaline leaching liquid are extracted and purified, wherein a kerosene solution containing primary amine N1923 serves as an extracting agent for extraction; and thirdly, reextraction separating and recycling of tungsten and vanadium in an extracted organic phase are performed. According to a process for extracting tungsten and vanadium fromthe waste SCR denitration catalyst in an alkaline leaching manner, due to the fact that waste catalyst powder and the NaOH solution are subjected to one time of leaching in a high pressure state, a liquid phase containing Na2WO4 and Na2VO3 can be obtained, efficient leaching of tungsten and vanadium is achieved, the W leaching rate reaches 97.46%, the V leaching rate reaches 88.6%, it is also kept that crystalline grains of TiO2 are anatase, and anatase can be reused as a catalyst carrier.

Description

technical field [0001] The invention belongs to the field of catalyst regeneration, and in particular relates to a method for recovering metal-containing catalysts. Background technique [0002] With the rapid development of industry, environmental damage such as smog and acid rain caused by automobile exhaust and industrial exhaust pollution has attracted more and more attention. Toxic nitrogen compounds (NO), sulfur compounds (SO2), and hydrocarbons (HC), their direct emissions are the main causes of acid rain, photochemical smog, and ozone depletion. In order to effectively treat nitrogen oxides and other toxic substances in various exhaust gases, it is necessary to denitrify the exhaust gas, and use a denitrification catalyst to convert nitrogen oxides into nitrogen and water. At present, the most widely used exhaust gas purification treatment is selective catalytic reduction (SCR) denitrification technology, and V 2 o 5 -WO 3 / TiO 2 Catalysts have gradually become ...

Claims

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Application Information

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IPC IPC(8): C22B7/00C22B34/22C22B34/36
CPCC22B7/008C22B34/225C22B34/365Y02P10/20
Inventor 席晓丽陈佳鹏马立文聂祚仁
Owner BEIJING UNIV OF TECH
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