CN102936049B - Method for extracting tungsten, titanium and vanadium from waste SCR (selective catalytic reduction) catalyst - Google Patents

Abstract

The invention discloses a method for extracting tungsten, titanium and vanadium from a waste SCR (selective catalytic reduction) catalyst, which comprises the following steps: crushing the waste SCR catalyst, adding a strongly alkaline solution, and reacting; filtering, separating, then adding strong acid into the sodium tungstate and sodium vanadate mixed solution, and reacting to obtain tungstic acid and a sodium salt and vanadic acid mixed solution; regulating the pH value of the sodium salt and vanadic acid mixed solution until precipitate is separated out, thus obtaining ammonium vanadate; then adding sulfuric acid into the tungsten-and-vanadium-removed SCR catalyst, and reacting to obtain a titanyl sulfate solution and solids such as aluminum slag and the like; then adding water into the titanyl sulfate solution, and hydrolyzing to obtain titanic acid and a waste acid solution; and finally, respectively calcining the obtained ammonium vanadate, tungstic acid and titanic acid to obtain vanadium pentoxide, tungsten trioxide and titanium dioxide. According to the invention, tungsten, titanium and vanadium can be extracted from the SCR catalyst through the reaction with strong alkali and strong acid at a low temperature, the equipment requirement is low, the energy consumption is low, some products having added values can be coproduced, and no secondary pollution is generated, thereby facilitating popularization and application.

Description

A method for extracting tungsten, titanium and vanadium from waste SCR catalyst

technical field

The invention belongs to the technical field of recycling waste catalysts, in particular to a method for extracting tungsten, titanium and vanadium from waste SCR catalysts.

Background technique

SCR (Selective Catalytic Reduction) catalysts are used in thermal power plants to remove nitrogen oxide pollutants produced by combustion, which also contain harmful substances such as V ₂ O ₅ . According to data, as of 2008, SCR devices of 20 million kilowatts of thermal power units have been put into operation in my country, and the installed capacity of SCR devices under construction in 2009 is 100 million kilowatts. The resulting problem of SCR catalyst recycling and reuse Also on the agenda. It is estimated that by 2010, the installed capacity of domestic SCR devices will reach 320 million kilowatts, and the initial filling capacity of catalysts will reach 260,000 m ³ . Calculated based on the three-year service life of SCR catalysts, by 2012, there will be about 260,000 m ³ of waste catalysts. If a large number of discarded catalysts are not properly treated, they will accumulate over time and form "urban mines", which will not only waste resources, but also cause serious environmental pollution, the most serious of which is groundwater pollution. , Polluted water will have a great impact on human health. Discarded SCR catalysts are special items and must be disposed of reasonably according to certain norms and regulations. Therefore, research and development of catalyst recycling technologies are very important both from the perspective of economic development and environmental protection (Wang Hu, recycling of metal oxides in SCR denitrification catalysts [J]. Gansu Electric Power Technology, 2011 (02): 29-30).

Although the regeneration of spent SCR catalysts has been successfully operated abroad, there is no relevant catalyst regeneration experience in China. Moreover, some sources believe that the cost of regeneration of spent catalysts is very expensive. Therefore, due to economic and other considerations, it is particularly important to treat or utilize waste catalysts. Especially with the large-scale construction of selective reduction and denitrification projects in thermal power plants, the amount of waste catalysts has increased sharply. The rational disposal and utilization of sci-tech workers will be a new research topic for scientific and technological workers (Xu Furong, Zhou Lirong; Discussion on the treatment plan for the invalid catalyst of the SCR denitrification device in the coal-fired power plant [J]. China Environmental Protection Industry, 2010, (11): 25- 27).

At present, other ways to dispose and utilize waste catalysts include: (1) landfill disposal; (2) return to catalyst sellers; (3) use as cement raw materials or aggregates; (4) co-firing with coal after grinding; (5) Recycling useful metal materials. Among them, recycling the useful metal materials is a more environmentally friendly treatment method. The method is to extract the useful parts of the discarded catalyst through various physical and chemical methods for recycling. Because through the recycling of waste catalyst, about 800kg of TiO ₂ can be recovered per cubic meter of waste catalyst; about 90kg of WO ₃ +V ₂ O ₅ +MoO ₃ can be recovered. At that time, if the waste catalysts mentioned above can be recycled, 208,000 tons of TiO ₂ and 2,340 tons of WO ₃ +V ₂ O ₅ +MoO ₃ can be recovered. According to the current market TiO ₂ : 15,000-20,000 yuan/ton; WO ₃ : 15-160,000 yuan/ton; V ₂ O ₅ : 11-120,000 yuan/ton; MoO ₃ : 15-160,000 yuan/ton Based on the price calculation, each cubic meter of waste catalyst can produce an output value of at least 25,500 yuan, and its total output value will reach at least 6.63 billion yuan. If calculated according to 30% profit, it can generate nearly 2 billion yuan of profit per year (Wang Hu, Recycling of metal oxides in SCR denitrification catalysts [J]. Gansu Electric Power Technology, 2011 (02): 29-30). Even so, the price of this treatment method is still relatively expensive, so it has not been applied on a large scale. However, with the advancement of technology, this treatment method is expected to become the mainstream treatment method (Xu Furong, Discussion on the treatment plan for the spent catalyst of the SCR denitrification unit of Zhou Lirong Coal-fired Power Plant [J]. China Environmental Protection Industry, 2010, (11): 25-27 ).

The Chinese invention patent No. 201010254247 discloses "a method for recovering metal oxides from waste flue _gas denitrification catalysts". CO ₃ and mixed, pulverized, and then roasted at high temperature. After the sintered block is crushed, it is thrown into hot water and stirred for leaching. Add sulfuric acid to the obtained titanate, filter, wash with water, and roast to obtain TiO ₂ . Add sulfuric acid to the filtrate after leaching to adjust the pH to 8.0~9.0, and then add excess NH ₄ Cl to precipitate vanadium. The filtered NH ₄ VO ₃ is pyrolyzed to obtain the finished product of V ₂ O ₅ . Add hydrochloric acid to the filtrate after vanadium precipitation to adjust the pH value to 4.5~5.0, and then add CaCl ₂ to precipitate molybdenum and tungsten. MoO ₃ and WO ₃ can be obtained by filtering CaMoO ₄ and CaWO ₄ obtained by treating with hydrochloric acid and then roasting. Because this method needs to be roasted at high temperature many times, the equipment requirements are high, the investment is large, the energy consumption is high, and this method needs to use excessive sodium carbonate, which will produce a large amount of carbon dioxide gas and cause serious pollution to the environment.

Contents of the invention

The object of the present invention is to provide a method for extracting tungsten, titanium and vanadium from waste SCR catalysts in view of the above-mentioned deficiencies in the prior art.

The method for extracting tungsten, titanium and vanadium from the waste SCR catalyst provided by the present invention, the process steps and conditions of the method are as follows:

1) Pulverize the waste SCR catalyst to a particle size of 100-200 mesh, then add a strong alkali solution with a mass percentage concentration of 20-30%, react at a temperature of 150-200°C for 3-6 hours, and filter and separate to obtain detungsten and vanadium The mixed solution of SCR catalyst, sodium tungstate and sodium vanadate, the mass ratio of waste SCR catalyst to strong alkali is 10:3-6;

2) First, according to the mass ratio of strong acid to sodium tungstate and sodium vanadate solution is 1:3~6, make it into a strong acid solution with a mass percentage concentration of 70~80%, then add sodium tungstate and sodium vanadate to mix In the solution, react at 150-200°C for 1-4 hours, filter and separate to obtain a mixed solution of tungstic acid solid, sodium salt, and vanadic acid, and then add ammonia water to the mixed solution of sodium salt and vanadic acid to adjust the pH value to 7.00-8.00 , precipitated out, filtered and separated to obtain ammonium vanadate and ammonium salt solution, and the ammonium salt solution was concentrated and cooled to crystallize to obtain ammonium salt solid;

3) The mass ratio of sulfuric acid to the SCR catalyst for detungsten and vanadium obtained in step 1) is 10-14:1 to form a sulfuric acid solution with a mass percentage concentration of 90-98%, and then add the SCR catalyst for detungsten and vanadium , react at 200-250°C for 2-4 hours, filter and separate titanyl sulfate solution and aluminum slag and other solids;

4) Add water to the titanyl sulfate solution at a volume ratio of 1:10~13, hydrolyze at 80~100°C for 1~2 hours, filter and separate titanic acid solid and waste acid solution;

5) The ammonium vanadate, tungstic acid and titanic acid obtained in the above steps are calcined according to the existing technology to obtain vanadium pentoxide, tungsten trioxide and titanium dioxide respectively.

The tungstic acid solid obtained in step 2) of the above method can be purified in this way: add ammonia water to the tungstic acid solid at a mass ratio of 1:20-30, and then react at 100-120°C for 1-3 hours. Filter and separate to obtain ammonium tungstate solution and silicate filter cake, then add a strong acid solution with a mass percentage concentration of 70-80% to the ammonium tungstate solution, acidify at 120-150°C for 1-3 hours, filter and separate to obtain high-purity Tungstic acid solid and ammonium salt solution, the mass ratio of ammonium tungstate solution to strong acid is 3~5:1;

The mass ratio of the spent SCR catalyst to the strong base in step 1) of the above method is preferably 10:3~5, the reaction temperature is preferably 150~180°C, and the reaction time is preferably 3~5 hours.

The mass ratio of the strong acid to sodium tungstate and sodium vanadate solution described in step 2) of the above method is preferably 1:3~5, and the reaction time is preferably 1~3 hours.

The reaction time described in step 3) of the above method is preferably 2 to 3 hours.

The strong base described in the above method is preferably sodium hydroxide or potassium hydroxide; the strong acid is preferably any one of sulfuric acid, hydrochloric acid or nitric acid.

Compared with prior art, the present invention has the advantages of:

1. Since the present invention does not require multiple roasting reactions at high temperatures, useful metals such as tungsten, titanium, vanadium, etc. can be extracted step by step from the SCR catalyst by reacting with strong alkali and/or strong acid at a lower temperature , so it not only has low equipment requirements and low energy consumption, but also effectively solves the problem of SCR catalyst polluting the environment.

2. Since the present invention only needs to use some conventional raw materials such as alkali, acid, and ammonia in the process of extracting metals such as tungsten, vanadium, and silicon, the price is low, and the material consumption is small, so the extraction cost is low, and it is easier to popularize and apply.

3, because the silicon-alumina slag that the present invention produces in extracting the metal process such as tungsten, vanadium, silicon can be used as the raw material of producing wall body material, and ammonium salt etc. can be used as fertilizer, and hydrolysis water can be recycled, thereby this method The designed process route can not only co-produce some value-added products to reduce production costs, but also will not produce secondary pollution, which is very in line with the requirements of modern clean production.

4. Because the process of the present invention is simple and mature, the conditions are easy to control, easy to master, and the production cost is low, thus providing a path that can be applied on a large scale for extracting and recovering metal oxides from waste catalysts by chemical methods for recycling.

Detailed ways

Examples are given below to further illustrate the present invention.

Example 1

(1) Add the discarded SCR catalyst crushed to 120 mesh into 20% sodium hydroxide solution by mass percentage, react at a temperature of 200°C for 3 hours, and filter and separate to obtain the SCR catalyst for detungsten and vanadium, sodium tungstate and vanadic acid Sodium mixed solution, wherein the waste SCR catalyst and sodium hydroxide are in a mass ratio of 10:6;

(2) First, according to the mass ratio of sulfuric acid to sodium tungstate and sodium vanadate mixed solution of 1:3, make it into a sulfuric acid solution with a mass percentage concentration of 70%, and then add it to the mixed solution of sodium tungstate and sodium vanadate , reacted at 150°C for 4 hours, filtered and separated to obtain a mixed solution of tungstic acid solid, sodium sulfate and sodium vanadate, then added ammonia water to the mixed solution of sodium sulfate and sodium vanadate to adjust the pH value to 7.00, precipitated, separated by filtration Ammonium vanadate solid and ammonium salt solution are obtained, the ammonium salt solution is concentrated and cooled to crystallize to obtain ammonium salt solid, and ammonia water is added to the tungstic acid solid at a mass ratio of 1:20, and then reacted at 120°C for 3 hours, filtered and separated to obtain tungsten Ammonium acid solution and silicic acid filter cake, continue to add sulfuric acid solution with a mass percentage concentration of 70% to the ammonium tungstate solution, acidify at 120°C for 1 hour, filter and separate to obtain high-purity tungstic acid solid and ammonium salt solution, tungsten The mass ratio of ammonium acid solution to sulfuric acid is 3:1;

(3) Sulfuric acid is made into a sulfuric acid solution with a mass percentage concentration of 90% according to the mass ratio of sulfuric acid to the SCR catalyst for detungsten and vanadium obtained in step 1), and then added to the SCR catalyst for detungsten and vanadium. React at 250°C for 2 hours, filter and separate titanyl sulfate solution and solids such as aluminum slag, then add water to the titanyl sulfate solution at a volume ratio of 1:13, and hydrolyze at 100°C for 1 hour, filter and separate to obtain titanic acid Solid and spent acid solution (recyclable);

(4) Calcining and decomposing the ammonium vanadate solid obtained in the above steps at 800~850°C to obtain vanadium pentoxide, calcining the high-purity tungstic acid solid at 700~750°C to obtain tungsten trioxide, and calcining the solid titanate at 650~850°C Calcined at ℃ to get titanium dioxide.

Example 2

(1) Add the discarded SCR catalyst crushed to 200 mesh into a 30% potassium hydroxide solution by mass percentage, react at a temperature of 180°C for 5.5 hours, and filter and separate to obtain the SCR catalyst for detungsten and vanadium, sodium tungstate and vanadic acid Sodium mixed solution, wherein the waste SCR catalyst and potassium hydroxide are in a mass ratio of 10:4.5;

(2) First, according to the mass ratio of sulfuric acid to sodium tungstate and sodium vanadate mixed solution of 1:4.5, make it into a sulfuric acid solution with a mass percentage concentration of 76%, and then add it to the mixed solution of sodium tungstate and sodium vanadate , reacted at 160°C for 2.5 hours, filtered and separated to obtain a mixed solution of tungstic acid solid, sodium sulfate and sodium vanadate, then added ammonia water to the mixed solution of sodium sulfate and sodium vanadate to adjust the pH value to 7.20, precipitated, separated by filtration Ammonium vanadate solid and ammonium salt solution are obtained, the ammonium salt solution is concentrated and cooled to crystallize to obtain ammonium salt solid, and ammonia water is added to the tungstic acid solid at a mass ratio of 1:30, then reacted at 105°C for 3 hours, filtered and separated to obtain tungsten ammonium tungstate solution and silicic acid filter cake, continue to add sulfuric acid solution with a mass percentage concentration of 80% to the ammonium tungstate solution, acidify at 130°C for 3 hours, filter and separate to obtain high-purity tungstic acid solid and ammonium salt solution, tungsten The mass ratio of ammonium acid solution to sulfuric acid is 5:1;

(3) Sulfuric acid is made into a sulfuric acid solution with a mass percentage concentration of 98% according to the mass ratio of sulfuric acid to the SCR catalyst for detungsten and vanadium obtained in step 1), and then added to the SCR catalyst for detungsten and vanadium. React at 200°C for 4 hours, filter and separate titanyl sulfate solution and solids such as aluminum slag, then add water to the titanyl sulfate solution at a volume ratio of 1:10, and hydrolyze at 90°C for 1.5 hours, filter and separate to obtain titanic acid solid and spent acid solutions;

(4) Same as embodiment 1, omitted.

Example 3

(1) Add the discarded SCR catalyst crushed to 170 mesh into 26% sodium hydroxide solution by mass percentage, react at a temperature of 150°C for 4 hours, filter and separate to obtain the SCR catalyst for detungsten and vanadium, sodium tungstate and vanadic acid Sodium mixed solution, wherein waste SCR catalyst and sodium hydroxide are by mass ratio 10: 5;

(2) First, according to the mass ratio of sulfuric acid to sodium tungstate and sodium vanadate mixed solution as 1: 5, make it into a sulfuric acid solution with a mass percentage concentration of 80%, and then add it to the mixed solution of sodium tungstate and sodium vanadate , reacted at 170°C for 3.5 hours, filtered and separated to obtain a mixed solution of tungstic acid solid, sodium sulfate and sodium vanadate, then added ammonia water to the mixed solution of sodium sulfate and sodium vanadate to adjust the pH value to 8.00, precipitated, separated by filtration Ammonium vanadate solid and ammonium salt solution are obtained, the ammonium salt solution is concentrated and cooled to crystallize to obtain ammonium salt solid, and ammonia water is added to the tungstic acid solid at a mass ratio of 1:24, and then reacted at 120°C for 2 hours, filtered and separated to obtain tungsten ammonium tungstate solution and silicic acid filter cake, continue to add sulfuric acid solution with a mass percentage concentration of 74% to the ammonium tungstate solution, acidify at 150°C for 2.5 hours, filter and separate to obtain high-purity tungstic acid solid and ammonium salt solution, tungsten The mass ratio of ammonium acid solution to sulfuric acid is 4.5:1;

(3) The mass ratio of sulfuric acid to the SCR catalyst for detungsten and vanadium obtained in step 1) is 12:1 to form a sulfuric acid solution with a mass percentage concentration of 96%, and then add it to the SCR catalyst for detungsten and vanadium. React at 240°C for 3.5 hours, filter and separate titanyl sulfate solution and solids such as aluminum slag, then add water to the titanyl sulfate solution at a volume ratio of 1:11, and hydrolyze at 100°C for 1 hour, filter and separate to obtain titanic acid solid and spent acid solutions;

(4) Same as embodiment 1, omitted.

Example 4

(1) Add the discarded SCR catalyst crushed to 140 mesh into a potassium hydroxide solution with a concentration of 22% by mass, react at a temperature of 170°C for 6 hours, and filter and separate to obtain the SCR catalyst for detungsten and vanadium, sodium tungstate and vanadic acid Sodium mixed solution, wherein the waste SCR catalyst and potassium hydroxide are in a mass ratio of 10:3.5;

(2) First, according to the mass ratio of hydrochloric acid, sodium tungstate and sodium vanadate mixed solution as 1: 3.5, make it into a hydrochloric acid solution with a mass percentage concentration of 72%, and then add sodium tungstate and sodium vanadate mixed solution , reacted at 180°C for 2 hours, filtered and separated to obtain a mixed solution of tungstic acid solid, sodium chloride and sodium vanadate, then added ammonia water to the mixed solution of sodium chloride and sodium vanadate to adjust the pH value to 7.60, and precipitated out. Separate by filtration to obtain ammonium vanadate solid and ammonium salt solution. The ammonium salt solution is concentrated and cooled to crystallize to obtain ammonium salt solid. Add ammonia water to the tungstic acid solid at a mass ratio of 1:26, then react at 110°C for 2.5 hours, and separate by filtration. To obtain ammonium tungstate solution and silicic acid filter cake, continue to add hydrochloric acid solution with a mass percentage concentration of 78% to the ammonium tungstate solution, acidify and react at 125°C for 2 hours, filter and separate to obtain high-purity tungstate solid and ammonium salt solution , the mass ratio of ammonium tungstate solution to hydrochloric acid is 3:1;

(3) The mass ratio of sulfuric acid to the SCR catalyst for detungsten and vanadium obtained in step 1) is 12:1 to form a sulfuric acid solution with a mass percent concentration of 92%, and then add it to the SCR catalyst for detungsten and vanadium. React at 220°C for 3 hours, filter and separate titanyl sulfate solution and aluminum slag and other solids, then add water to the titanyl sulfate solution at a volume ratio of 1:12, and hydrolyze at 85°C for 1.5 hours, filter and separate to obtain titanic acid solid and spent acid solutions;

(4) Same as embodiment 1, omitted.

Example 5

(1) Add the discarded SCR catalyst crushed to 170 mesh into 24% potassium hydroxide solution by mass percentage, react at a temperature of 190°C for 3.5 hours, filter and separate to obtain the SCR catalyst for detungsten and vanadium, sodium tungstate and vanadic acid Sodium mixed solution, wherein the waste SCR catalyst and potassium hydroxide are in a mass ratio of 10:4;

(2) First, according to the mass ratio of hydrochloric acid, sodium tungstate and sodium vanadate mixed solution at 1:4, make it into a hydrochloric acid solution with a mass percentage concentration of 78%, and then add it into the mixed solution of sodium tungstate and sodium vanadate , reacted at 190°C for 1 hour, filtered and separated to obtain a mixed solution of tungstic acid solid, sodium chloride and sodium vanadate, then added ammonia water to the mixed solution of sodium chloride and sodium vanadate to adjust the pH value to 7.80, and precipitated. Ammonium vanadate solid and ammonium salt solution were separated by filtration, the ammonium salt solution was concentrated and cooled to crystallize to obtain ammonium salt solid, and ammonia water was added to the tungstic acid solid at a mass ratio of 1:28, then reacted at 100°C for 1 hour, and separated by filtration Obtain ammonium tungstate solution and silicic acid filter cake, continue to add hydrochloric acid solution with a mass percentage concentration of 72% to the ammonium tungstate solution, acidify and react at 140°C for 1.5 hours, filter and separate to obtain high-purity tungstate solid and ammonium salt solution , the mass ratio of ammonium tungstate solution to sulfuric acid is 3.5:1;

(3) The mass ratio of sulfuric acid to the SCR catalyst for detungsten and vanadium obtained in step 1) is 11:1 to form a sulfuric acid solution with a mass percentage concentration of 94%, and then add it to the SCR catalyst for detungsten and vanadium. React at 230°C for 2.5 hours, filter and separate to obtain solids such as titanyl sulfate solution and aluminum slag (, then add water to the titanyl sulfate solution at a volume ratio of 1:10, and hydrolyze at 95°C for 1.5 hours, filter and separate to obtain titanium Acid solids and spent acid solutions;

(4) Same as embodiment 1, omitted.

Example 6

(1) Add the discarded SCR catalyst crushed to 100 mesh into 28% sodium hydroxide solution by mass percentage, react at a temperature of 160°C for 4.5 hours, filter and separate to obtain the SCR catalyst for detungsten and vanadium, sodium tungstate and vanadic acid Sodium mixed solution, wherein the waste SCR catalyst and sodium hydroxide are in a mass ratio of 10:5.5;

(2) Firstly, according to the mass ratio of nitric acid, sodium tungstate and sodium vanadate mixed solution at 1:5, make it into a nitric acid solution with a mass percentage concentration of 74%, and then add sodium tungstate and sodium vanadate mixed solution , reacted at 200°C for 3 hours, filtered and separated to obtain a mixed solution of tungstic acid solid, sodium nitrate and sodium vanadate, then added ammonia water to the mixed solution of sodium nitrate and sodium vanadate to adjust the pH value to 7.40, precipitated, separated by filtration Ammonium vanadate solid and ammonium salt solution are obtained, ammonium salt solution is concentrated and cooled to crystallize to obtain ammonium salt solid, and ammonia water is added to tungstic acid solid at a mass ratio of 1:22, and then reacted at 115°C for 1.5 hours, filtered and separated to obtain tungsten ammonium tungstate solution and silicic acid filter cake, continue to add nitric acid solution with a mass percentage concentration of 76% to the ammonium tungstate solution, acidify at 145°C for 2.5 hours, filter and separate to obtain high-purity tungstic acid solid and ammonium salt solution, tungsten The mass ratio of ammonium acid solution and nitric acid is 4:1;

(3) Sulfuric acid is made into a sulfuric acid solution with a mass percentage concentration of 98% according to the mass ratio of sulfuric acid to the SCR catalyst for detungsten and vanadium obtained in step 1), and then added to the SCR catalyst for detungsten and vanadium. React at 210°C for 4 hours, filter and separate titanyl sulfate solution and aluminum slag and other solids, then add water to the titanyl sulfate solution at a volume ratio of 1:13, and hydrolyze at 80°C for 2 hours, filter and separate to obtain titanic acid solid and spent acid solutions;

(4) Same as embodiment 1, omitted.

Example 7

(1) Add the discarded SCR catalyst crushed to 200 mesh into 20% sodium hydroxide solution by mass percentage, react at a temperature of 180°C for 5 hours, filter and separate to obtain the SCR catalyst for detungsten and vanadium, sodium tungstate and vanadic acid Sodium mixed solution, wherein the waste SCR catalyst and sodium hydroxide are in a mass ratio of 10:3;

(2) First, according to the mass ratio of nitric acid, sodium tungstate and sodium vanadate mixed solution at 1:4, make it into a nitric acid solution with a concentration of 70% by mass percentage, and then add it into the mixed solution of sodium tungstate and sodium vanadate , reacted at 180°C for 1.5 hours, filtered and separated to obtain a mixed solution of tungstic acid solid, sodium nitrate and sodium vanadate, then added ammonia water to the mixed solution of sodium nitrate and sodium vanadate to adjust the pH value to 7.40, precipitated, separated by filtration Ammonium vanadate solid and ammonium salt solution are obtained, the ammonium salt solution is concentrated and cooled to crystallize to obtain ammonium salt solid, and ammonia water is added to the tungstic acid solid at a mass ratio of 1:26, and then reacted at 100°C for 2 hours, filtered and separated to obtain tungsten ammonium tungstate solution and silicic acid filter cake, continue to add 80% nitric acid solution to the ammonium tungstate solution, acidify at 135°C for 3 hours, filter and separate to obtain high-purity tungstic acid solid and ammonium salt solution, tungsten The mass ratio of ammonium acid solution and nitric acid is 5:1;

(3) Sulfuric acid is made into a sulfuric acid solution with a mass percentage concentration of 90% according to the mass ratio of sulfuric acid to the SCR catalyst for detungsten and vanadium obtained in step 1), and then added to the SCR catalyst for detungsten and vanadium. React at 230°C for 3 hours, filter and separate titanyl sulfate solution and solids such as aluminum slag, then add water to the titanyl sulfate solution at a volume ratio of 1:10, and hydrolyze at 95°C for 2 hours, filter and separate to obtain titanic acid solid and spent acid solutions;

(4) Same as embodiment 1, omitted.

In addition, it should be noted that, the specific examples described in this specification may have different formulations, names of processes, and the like. Any equivalent or simple changes made according to the features and principles described in the patent concept of the present invention are included in the protection scope of the present invention. Those skilled in the technical field of the present invention can make various modifications or supplements to the described specific embodiments or adopt similar methods to replace them, as long as they do not deviate from the scope defined by the claims of the present invention, all should belong to the present invention. protection scope of the invention.

Claims (8)

1. A method for extracting tungsten, titanium, vanadium from waste SCR catalyst, the process steps and conditions of the method are as follows: 1) Pulverize the waste SCR catalyst to a particle size of 100-200 mesh, then add a strong alkali solution with a mass percentage concentration of 20-30%, react at a temperature of 150-200°C for 3-6 hours, and filter and separate to obtain detungsten and vanadium A mixed solution of SCR catalyst, sodium tungstate and sodium vanadate, wherein the mass ratio of waste SCR catalyst to strong base is 10:3-6; 2) First, according to the mass ratio of strong acid to sodium tungstate and sodium vanadate solution is 1:3~6, make it into a strong acid solution with a mass percentage concentration of 70~80%, then add sodium tungstate and sodium vanadate to mix In the solution, react at 150-200°C for 1-4 hours, filter and separate to obtain a mixed solution of tungstic acid solid, sodium salt, and vanadic acid, then add ammonia water to the obtained tungstic acid solid at a mass ratio of 1:20-30, and then React at 100-120°C for 1-3 hours, filter and separate to obtain ammonium tungstate solution and silicate filter cake, then add a strong acid solution with a mass percentage concentration of 70-80% in the ammonium tungstate solution, and acidify at 120-150°C After 1 to 3 hours, filter and separate to obtain high-purity tungstic acid solid and ammonium salt solution, the mass ratio of ammonium tungstate solution to strong acid is 3 to 5:1, and then add ammonia water to the obtained mixed solution of sodium salt and vanadic acid to adjust When the pH value is 7-8, the precipitate is separated out, and the ammonium vanadate and ammonium salt solution are separated by filtration, and the ammonium salt solution is concentrated and cooled to crystallize to obtain the ammonium salt solid; 3) Make a sulfuric acid solution with a mass percent concentration of 90-98% by mass ratio of sulfuric acid to the SCR catalyst for detungsten and vanadium obtained in step 1), and then add the SCR catalyst for detungsten and vanadium , react at 200-250°C for 2-4 hours, filter and separate titanyl sulfate solution and aluminum slag and other solids; 4) Add water to the titanyl sulfate solution at a volume ratio of 1:10-13, hydrolyze at 80-100°C for 1-2 hours, and separate by filtration to obtain solid titanic acid and waste acid solution; 5) Calcining the ammonium vanadate, tungstic acid and titanic acid obtained in the above steps according to the existing technology can obtain vanadium pentoxide, tungsten trioxide and titanium dioxide respectively, Wherein said strong acid is sulfuric acid or nitric acid. 2. The method for extracting tungsten, titanium and vanadium from waste SCR catalyst according to claim 1, characterized in that the mass ratio of waste SCR catalyst and strong base in step 1) of the method is 10:3～ 5. The reaction temperature is 150-180°C, and the reaction time is 3-5 hours. 3. according to the method for extracting tungsten, titanium, vanadium from waste SCR catalyst described in claim 1 or 2, it is characterized in that the quality of the strong acid described in the step 2) of this method and sodium tungstate, sodium vanadate solution The ratio is 1:3~5, and the reaction time is 1~3 hours. 4. The method for extracting tungsten, titanium and vanadium from waste SCR catalyst according to claim 1 or 2, characterized in that the reaction time in step 3) of the method is 2-3 hours. 5. The method for extracting tungsten, titanium and vanadium from waste SCR catalyst according to claim 3, characterized in that the reaction time in step 3) of the method is 2-3 hours. 6. The method for extracting tungsten, titanium and vanadium from waste SCR catalyst according to claim 1 or 2, characterized in that the strong base described in the method is sodium hydroxide or potassium hydroxide. 7. The method for extracting tungsten, titanium and vanadium from waste SCR catalyst according to claim 4, characterized in that the strong base described in the method is sodium hydroxide or potassium hydroxide. 8. The method for extracting tungsten, titanium and vanadium from waste SCR catalyst according to claim 5, characterized in that the strong base described in the method is sodium hydroxide or potassium hydroxide.