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Method for recycling ammonium paratungstate by using waste SCR catalyst

A technology of SCR catalyst and ammonium paratungstate, which is applied in chemical instruments and methods, preparation of vanadium compounds, preparation of tungsten compounds, etc., can solve the problems of wasting lye, high cost of chemicals, and no purification process for titanium dioxide filter residues, so as to save production. cost effect

Pending Publication Date: 2021-02-19
上海盈华化工有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the method proposed by Chinese patent CN107419104B focuses on the recovery of tungsten and vanadium, and does not recycle the lye in the production process, but directly adds acid to condition the pH, which wastes lye and requires a large amount of acid to adjust the pH. The production process requires a lot of chemical costs, and there is no further purification process for the titanium dioxide filter residue
[0006] It can be seen from this that in related technologies, the related technology for recovering resources from spent denitrification catalysts is not yet mature, that is to say, there is still room for improvement in the recovery rate and purification of existing methods in terms of cleaning, energy saving and recycling.

Method used

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  • Method for recycling ammonium paratungstate by using waste SCR catalyst
  • Method for recycling ammonium paratungstate by using waste SCR catalyst
  • Method for recycling ammonium paratungstate by using waste SCR catalyst

Examples

Experimental program
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Effect test

Embodiment 1

[0036] (1) Alkali leaching reaction: Alkali leaching reaction is carried out on the crushed and ground spent SCR denitration catalyst powder, and titanium slag and filtrate are obtained by filtration.

[0037] (2) Extraction of tungsten and vanadium: use sulfuric acid quaternary ammonium salt to carry out tungsten and vanadium extraction on the filtrate after step (1), to obtain tungsten-containing liquid and vanadium-containing organic phase, wherein the ratio of sulfuric acid quaternary ammonium salt is O / A =1:1, the temperature is 10-30 degrees, the pH of the feed liquid is 9-12, and the single-stage extraction rate is 98%.

[0038] (3) Primary crystallization: Carry out crystallization operation on the tungsten-containing liquid to obtain mother liquid 1 and sodium tungstate crystals. Among them, the specific gravity of crystallization and mother liquid is controlled to be 1.60 mg / L during the primary crystallization process, and the NaOH content of mother liquid 1 is 600-7...

Embodiment 2

[0047] On the basis of the above-mentioned embodiments, the embodiments of the present application further elaborate the steps, as figure 2 As shown, in addition to the extraction of ammonium paratungstate, it also includes the extraction of titanium powder.

[0048] (1) Alkali leaching reaction: Alkali leaching reaction is carried out on the crushed and ground spent SCR denitration catalyst powder, and titanium slag and filtrate are obtained by filtration.

[0049] (10) Acidolysis: use dilute sulfuric acid to acidolyze the titanium slag treated in step (1) to obtain high-titanium powder. Wherein, the concentration of the dilute sulfuric acid in step (10) is 2-8%, and the purity of the high-titanium powder is more than or equal to 95%.

[0050]In the embodiment of the present application, on the basis of the above-mentioned embodiments, not only the recycling of alkali solution is realized, but also the recovery of titanium powder by acidolysis of the waste titanium slag aft...

Embodiment 3

[0052] On the basis of the above-mentioned embodiments, the embodiments of the present application further elaborate the steps, as image 3 As shown, in addition to the extraction of ammonium paratungstate and titanium powder, it also includes the extraction of ammonium metavanadate.

[0053] (1) Alkali leaching reaction: Alkali leaching reaction is carried out on the crushed and ground spent SCR denitration catalyst powder, and titanium slag and filtrate are obtained by filtration.

[0054] (2) Extraction of tungsten and vanadium: extracting tungsten and vanadium from the filtrate treated in step (1) with sulfuric acid quaternary ammonium salt to obtain a tungsten-containing liquid and a vanadium-containing organic phase.

[0055] (11) Stripping: use 0.5mol / L NaOH and 1.5mol / L Na 2 CO 3 Back-extracting the vanadium-containing organic phase after the treatment in step (2).

[0056] (12) Ammonia precipitation: Precipitate the material after step (11) stripping with ammonia w...

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Abstract

The invention discloses a method for recycling ammonium paratungstate by using a waste SCR catalyst, which is used for recycling alkali liquor after an alkaline leaching reaction is finished, so thatthe production cost is further saved, and the recycled alkali liquor is used for carrying out water-soluble operation on crystals so as to realize the extraction of ammonium paratungstate, on the basis of cyclic utilization of the alkali liquor, PH adjustment through a large amount of acid liquor is avoided, and use of harmful chemicals is effectively reduced on the basis of improving the process.

Description

technical field [0001] The embodiment of the present invention relates to the field of recovery of denitrification catalysts, in particular to a method for recovering ammonium paratungstate by utilizing a spent SCR catalyst. Background technique [0002] Selective Catalytic Reduction (SCR) denitrification technology is an efficient and stable flue gas denitrification technology in related technologies. Among them, SCR catalyst is a key material for removing nitrogen oxides in flue gas with high efficiency and low cost, and is widely used in thermal power plants. Coal flue gas denitrification process, and due to the erosion of flue gas and the accumulation of various impurities in the catalyst, the life of the catalyst is only about 3 to 4 years. [0003] The main component of the SCR catalyst is titanium dioxide (containing about TiO 2 75~85%), tungsten oxide (contains about WO 3 4-8%) and precious metal compounds such as vanadium pentoxide, a large number of decommission...

Claims

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Application Information

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IPC IPC(8): C01G41/00C01G31/00C22B7/00C22B34/12
CPCC01G41/003C01G31/003C22B7/007C22B7/008C22B34/125C22B34/1254C01P2006/80Y02P10/20
Inventor 苏振宇朱华盛王伟
Owner 上海盈华化工有限公司
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