CN107416903A - A kind of method for handling spent vanadium catalyst - Google Patents

Abstract

The invention belongs to the field of waste catalyst treatment and discloses a method for treating waste vanadium catalysts. The steps of the method include grinding, water immersion, reduction leaching, separation of vanadium and potassium, alkali dissolution and impurity removal, pH adjustment, vanadium precipitation and roasting, The leaching slag, V ₂ O ₅ solid and potassium sulfate are obtained, and the leaching slag can be made into concrete. The invention adopts the method of water leaching first and then acid leaching, which greatly reduces the amount of acid used in the process of leaching vanadium, and does not need to use expensive extraction agents, which reduces production costs; sulfur dioxide is used as a reducing agent, effectively Utilizes the sulfur dioxide exhaust gas discharged from the factory to reduce environmental pollution; realizes the simultaneous recovery of vanadium and potassium, and also solves the problem of treating silicon dioxide, iron compounds and aluminum compounds in spent vanadium catalysts. It is an ideal No waste gas and waste residue discharge treatment method.

Description

A kind of method of processing spent vanadium catalyst

technical field

The invention belongs to the field of recovery and reuse of spent catalysts, and more specifically relates to a method for treating spent vanadium catalysts.

Background technique

There are 500,000 to 700,000 tons of solid waste catalysts produced every year in the world. If it is not treated, it will not only pollute the soil (vanadium pentoxide is a toxic substance, and its solubility in water is 8g/L), occupy a large amount of land (1 mu of land will be occupied for the storage of 10,000 tons of waste residue), but also cause rare and precious metal resources. waste.

Vanadium-containing catalysts are used in the production of sulfuric acid. The active component of the catalyst is vanadium pentoxide, the promoter is potassium sulfate, and the catalyst carrier is diatomaceous earth. In addition, this catalyst also contains small amounts of iron and aluminum compounds. After the vanadium catalyst is used for a period of time, the active component V ₂ O ₅ will be transformed into tetravalent vanadium without catalytic activity due to the poisonous effect of fluorine, acid mist, and fine dust contained in the gas. When the proportion of tetravalent vanadium is too high, the vanadium catalyst will be deactivated and become a waste vanadium catalyst. Therefore, the life of the vanadium catalyst is generally 2 to 10 years. Calculated according to the current output of domestic sulfuric acid plants, more than 10,000 tons of spent vanadium catalysts will be produced every year. The analysis results show that in the spent vanadium catalyst, the content of SiO ₂ is 50-70%, the content of K ₂ SO ₄ is 5-8%, the content of V ₂ O ₅ is 5-8%, and the content of Al ₂ O ₃ is 2-4%, and the content of Fe ₂ O ₃ is 1.5-3%. Therefore, the spent vanadium catalyst contains high recycling value. More importantly, the social and environmental benefits brought about by the recycling of spent catalysts are enormous.

There have been many studies on the recovery of vanadium from spent vanadium catalysts at home and abroad, and some achievements have been made, but there are still problems such as high recovery costs and difficulty in industrialization. Patent 201410037134.0 invented a method for recovering vanadium, potassium and silicon from spent vanadium catalysts, disclosing a method for recovering vanadium, potassium and silicon from spent vanadium catalysts. First, the spent vanadium catalysts were subjected to water leaching and reducing acid leaching, and the total leaching rate of vanadium was ≥95.0 %, silicon is separated from the vanadium and potassium transferred to the leaching solution in the form of leaching slag, and the leaching slag is prepared by alkali dissolution to prepare liquid sodium silicate to recover silicon; the vanadium and potassium in the leaching solution are separated by extraction: the raffinate phase is produced by evaporation and crystallization. Potassium sulfate is taken to recover potassium; the extract phase is prepared through back extraction, vanadium precipitation and roasting to prepare vanadium pentoxide to recover vanadium. The advantage of this application is that it realizes the recovery of vanadium, silicon and potassium in the spent vanadium catalyst. The weak point of this invention is: 1. the extraction agent will fail after using a certain number of times, resulting in high production cost; It is technically feasible, but economically infeasible; 3. The invention does not mention the treatment method for iron compounds and aluminum compounds in spent vanadium catalysts.

Another example is patent publication number: 201110397978.2, publication date: June 13, 2012, and the name of the invention is: a method for comprehensive recycling of spent vanadium catalysts. This application discloses a method for comprehensive recycling of spent vanadium catalysts. Using waste vanadium catalyst as raw material, firstly, by reductive acid leaching, vanadium and potassium are transferred to the liquid phase to realize the separation from _SiO2 precipitation, and _SiO2 is prepared by alkali dissolution to prepare liquid sodium silicate to recover _SiO2 ; vanadium in the liquid phase and potassium are added to lye to realize the separation of vanadium and potassium, and then prepare V ₂ O ₅ and K ₂ SO ₄ respectively. The method prepares V ₂ O ₅ , K ₂ SO ₄ and liquid sodium silicate from spent vanadium catalysts, realizes simultaneous recovery of vanadium, potassium and silicon, V ₂ O ₅ purity ≥ 98.3%, yield ≥ 92.0%, K ₂ The purity of SO ₄ is ≥51.2% based on K ₂ O, and the yield is ≥95%. Na ₂ O ≥7.7%, SiO ₂ ≥24.6% in liquid sodium silicate, and the yield is ≥93.2%. The advantage of this application is that the vanadium silicon potassium in the spent vanadium catalyst is successfully recovered without using an extractant. The weak point of this application is: 1. directly adopt reducing acid leaching, cause the consumption of acid is too large; 2. utilize the silicon dioxide in the waste vanadium catalyst to prepare liquid sodium silicate to reclaim silicon technically feasible, but It is not economically feasible; 3. The application does not mention the treatment method for iron compounds and aluminum compounds in the spent vanadium catalyst.

To sum up, how to design a method for treating spent vanadium catalysts with low recovery cost and easy industrialization is a difficult problem in the prior art.

Contents of the invention

The purpose of the present invention is to provide a method for treating spent vanadium catalysts in order to overcome the defects of the prior art. The method provides a low recovery cost and easy industrialized method for treating waste vanadium catalysts. The method of water leaching followed by acid leaching is adopted, and sulfur dioxide is used as a reducing agent, which reduces the amount of acid used and does not require the use of expensive extraction agents. It realizes the simultaneous recovery of vanadium and potassium, and also solves the problem of waste vanadium catalysts. It is an ideal treatment method without waste gas and waste slag discharge.

The above-mentioned purpose of the present invention is achieved through the following technical solutions:

A method for processing spent vanadium catalysts, comprising the following specific steps:

S1. Grinding the spent vanadium catalyst into granules, adding water to mix evenly, immersing in water at a temperature of 30-100° C. for 0.5-4 hours, separating the water-leaching products to obtain water-leaching liquid and water-leaching residue;

S2. Mix the acid solution and water leaching slag, react in an atmosphere of sulfur dioxide for 0.5 to 4 hours, and separate the product to obtain acid leaching solution and leaching slag I;

S3. Mix the water immersion solution in step S1 with the acid immersion solution in step S2, add KOH solution dropwise, adjust the pH to 6-8, react at 40-80°C for 30-120min, separate the product to obtain potassium sulfate Solution and filter cake I;

S4. Dissolving the filter cake I in the alkaline solution, adjusting the pH to 13-14, then adding an oxidizing agent, boiling to make the solution change from blue to yellow, and separating the product to obtain leaching residue II and filtrate I;

S5. Add the acidic solution dropwise to the filtrate I, adjust the pH to 4.7-10, and obtain the leaching residue III and the filtrate II;

S6. Add the ammonium salt solution or ammonia water dropwise to the filtrate II, adjust the pH to 8, react at room temperature for 30-90 minutes, separate the product, and obtain ammonium metavanadate precipitate;

S7. Precipitating ammonium metavanadate is heated to 300-500° C. in air or oxygen, kept for 1-2 hours, and then cooled to room temperature with the furnace to obtain a V ₂ O ₅ solid with a purity greater than 97.5%.

S8. Grind the leaching slag I, leaching slag II, and leaching slag III, mix them evenly, add them to the mixture of cement, medium sand, aggregate and reinforcing fiber and mix them, then add admixtures and water to mix, and stir for 2 to 4 minutes , to make concrete;

S9. Concentrate the potassium sulfate solution obtained in step S3 and cool down to crystallize to obtain potassium sulfate.

Preferably, the particle size of the particles in step S1 is 1-125 microns.

Preferably, the mass ratio of spent vanadium catalyst to water in step S1 is 1: (1.5-5).

Preferably, in step S2, the mass ratio of the acidic solution to the water leaching residue is (1.5-5):1, and the concentration of the sulfur dioxide is 5-99%.

Preferably, the acidic solution in steps S2 and S5 is more than one of sulfuric acid, nitric acid, citric acid or hydrochloric acid.

Preferably, the alkaline solution in step S4 is one or more of sodium hydroxide solution, potassium hydroxide solution or calcium hydroxide solution.

Preferably, the oxidant in step S4 is at least one of permanganate, sodium chlorate or hydrogen peroxide.

Preferably, the ammonium salt solution in step S6 is one or more of ammonium chloride, ammonium sulfate, ammonium bisulfate, ammonium nitrate, ammonium carbonate or ammonium bicarbonate.

Preferably, the components of the concrete in step S8 are as follows: 100-300 parts of leaching slag, 200-300 parts of cement; 300-600 parts of medium sand, 600-1000 parts of aggregate, 10-20 parts of reinforcing fiber, admixture 5-10 parts, 170-210 parts of water;

Preferably, the admixture includes 35 parts of polycarboxylate water reducer, 6 parts of silane coupling agent, 3 parts of polyvinylpyrrolidone, 2 parts of silicon carbide, 8 parts of silicon dioxide-coated titanium dioxide, and 5 parts of gelatin powder , 12 parts of bentonite, 10 parts of nano carbon powder, 4 parts of sodium gluconate and 4 parts of phenol acetate.

Preferably, the fineness modulus of the medium sand is 2.3-3, the aggregate is cinder, slag, blast furnace slag or stone, and the particle size of the aggregate is 10-20mm; the fineness of the aggregate is The modulus is 1.6-1.8; the cement is Portland cement, and the strength index of the Portland cement is 32.5 or 42.5; the reinforcing fiber is one or more of steel fiber, glass fiber or carbon fiber, and the The length of the reinforcing fiber is 9~30mm

Compared with the prior art, the present invention has the following beneficial effects:

1. The present invention adopts the method of first water leaching and then acid leaching, which greatly reduces the amount of acid used in the process of leaching vanadium, and does not need to use expensive extraction agents, which reduces production costs.

2. The present invention uses sulfur dioxide as the reducing agent, which not only reduces the production cost, but also effectively utilizes the sulfur dioxide waste gas discharged from the factory, thereby reducing the pollution to the environment.

3. The present invention realizes the synchronous recovery of vanadium and potassium, and also solves the problem of treating silicon dioxide, iron compounds and aluminum compounds in spent vanadium catalysts, and is an ideal discharge method without waste gas and waste residue.

Description of drawings

Fig. 1 is a process flow diagram of the present invention for treating spent vanadium catalysts.

detailed description

The content of the present invention will be further described below in conjunction with specific examples, but it should not be construed as a limitation of the present invention. Unless otherwise specified, the technical means used in the embodiments are conventional means well known to those skilled in the art. Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the technical field.

In the embodiment 1-3, the grinding device is a ball mill, and the solid-liquid separation device is a filter press; the reaction vessel is a high-pressure reactor, an enamel reactor, a stainless steel reactor or a glass reinforced plastic reactor; the reaction A pH value sensor, a temperature sensor and a pressure sensor are all installed in the container, and the heating device is a heating furnace.

Fig. 1 is a process flow diagram of the present invention for treating spent vanadium catalysts. The method for treating the spent vanadium catalyst will be specifically described below in conjunction with Examples 1-3.

Example 1

A method for processing spent vanadium catalyst, comprising the steps of:

1. Grinding: Send the spent vanadium catalyst to a ball mill for grinding until the particle size is less than 125 microns; the particle size is 125 microns, which is 120 mesh;

2. Water leaching: Mix the ground waste vanadium catalyst with water evenly, with a solid-to-liquid weight ratio of 1:4; leaching at 30°C for 2 hours; 30% of vanadium pentoxide and A mixture of vanadium tetroxide, 50% potassium sulfate. When 6≤pH≤8, pentavalent vanadium ions exist in the form of VO ₃ (OH) ^2- , V ₃ O ₉ ^3- , V ₄ O ₁₂ ^4- in water, and are hardly soluble in water. Vanadium tetroxide is easily soluble in water. The water leaching product is separated by a filter press to obtain a water immersion liquid and a water leaching residue; the water immersion liquid directly enters a vanadium and potassium separation process; and the water leaching residue enters a reduction leaching process.

3. Reduction leaching: Mix 3mol/L sulfuric acid solution and spent vanadium catalyst in a mass ratio of 5:1 to form a mixed solution, which is added to the FRP reactor; 99% sulfur dioxide, react for 2 hours; sulfur dioxide tail gas is absorbed with sodium hydroxide solution; the remaining vanadium oxide and potassium sulfate can be leached through reduction leaching; under normal temperature and pressure, 9.4 grams of sulfur dioxide can be dissolved per 100ml of water; two-thirds Sulfur dioxide dissolved in water reacts with water to form sulfurous acid; sulfurous acid can be used as a reducing agent to convert pentavalent vanadium into tetravalent vanadium that is easily soluble in water; use a filter press to separate the reduction and leaching products to obtain acid leaching solution and leaching Slag I.

4. Separation of vanadium and potassium: Add the water immersion solution in step 2 and the acid immersion solution in step 4 into the FRP reactor, then slowly add 1mol/L KOH solution, adjust the pH to 7, and react at 60°C 90 minutes; the purpose of using KOH solution is not to introduce impurity ions before separating the potassium sulfate solution; use a filter press to separate the vanadium and potassium separation products to obtain potassium sulfate solution and filter cake I.

5. Alkali dissolution and impurity removal: Dissolve the filter cake I obtained in step 4 in potassium hydroxide solution, and adjust the pH to be greater than 13 and less than 14. When 13≤pH≤14, the pentavalent vanadium ion exists in the form of VO ₄ ^3- in water and is easily soluble in water. Then add the oxidant sodium chlorate and boil to make the solution change from blue to yellow; at this time, the tetravalent vanadium has been converted into pentavalent vanadium; use a filter press to separate the alkali-dissolved impurity removal products to obtain leaching residue II and filtrate I ;

6. Adjust the pH: add the filtrate I obtained in step 5 into the glass fiber reinforced plastic reactor, then add hydrochloric acid solution dropwise, and adjust the pH to 8; obtain the leaching residue III and the filtrate II; adjust the pH value to 8 to facilitate the precipitation of ammonium metavanadate generate.

7. Precipitation of vanadium: add the filtrate II obtained by adjusting the pH to the reaction vessel, and then add ammonium sulfate solution dropwise; react at room temperature for 90 minutes; separate the product of vanadium precipitation with a filter press to obtain ammonium metavanadate precipitation.

8. Roasting: put the ammonium metavanadate precipitate obtained in step 7 into a heating furnace and heat to 420°C in an air atmosphere, keep it warm for 2 hours, and then cool to room temperature with the furnace to obtain a V ₂ O ₅ solid with a purity greater than 97%; The discharged NH ₃ waste gas is absorbed with hydrochloric acid solution to generate ammonium chloride solution, which is returned to the vanadium precipitation process.

9. Concrete production: Grind the leaching slag I, leaching slag II, and leaching slag III and mix them evenly, then mix them with cement, medium sand, aggregate, and reinforcing fibers, then add admixtures and water, and stir for 4 minutes to obtain concrete.

The quality of each component of the above concrete is as follows: 100 parts of leaching slag, 200 parts of Portland cement, the strength index of Portland cement is 32.5; 300 parts of medium sand with a fineness modulus of 2.7, and 600 parts of gravel. The particle size of the stone is 10mm-20mm, the powder content of the stone is 5.4%, the fineness modulus is 1.8, 20 parts of steel fiber, the length of the steel fiber is 9mm, 5 parts of admixture, and 170 parts of water.

Additives are 35 parts of polycarboxylate water reducer, 6 parts of silane coupling agent, 3 parts of polyvinylpyrrolidone, 2 parts of silicon carbide, 8 parts of silicon dioxide coated titanium dioxide, 5 parts of gelatin powder, 12 parts of bentonite, A mixture of 10 parts of nano carbon powder, 4 parts of sodium gluconate and 4 parts of phenol acetate.

10. Potassium sulfate production: the potassium sulfate solution obtained in step 4 is transported to the concentrator for concentration, distilled water is concentrated to obtain a concentrated solution; the concentrated solution is sent to the crystallization kettle for cooling and crystallization, and potassium sulfate with a purity greater than 98% is obtained solid.

Example 2

A method for processing spent vanadium catalyst, comprising the steps of:

1. Grinding: Send the spent vanadium catalyst to a ball mill for grinding until the particle size is less than 125 microns, which is 120 mesh.

2. Water leaching: Mix the ground waste vanadium catalyst with water evenly, with a solid-to-liquid weight ratio of 1:3; leaching at 100°C for 3 hours; 50% of vanadium pentoxide and Mixture of vanadium tetroxide, 70% potassium sulfate. When 6≤pH≤8, pentavalent vanadium ions exist in the form of VO ₃ (OH) ^2- , V ₃ O ₉ ^3- , V ₄ O ₁₂ ^4- in water, and are hardly soluble in water. Vanadium tetroxide is easily soluble in water. The water leaching product is separated by a filter press to obtain a water immersion liquid and a water leaching residue; the water immersion liquid directly enters a vanadium and potassium separation process; and the water leaching residue enters a reduction leaching process.

3. Reduction leaching: Mix 2mol/L sulfuric acid solution and spent vanadium catalyst in a mass ratio of 4:1 to form a mixed solution, which is added to the enamel reaction kettle; 99% sulfur dioxide, react for 2 hours; sulfur dioxide tail gas is absorbed with sodium hydroxide solution; the remaining vanadium oxide and potassium sulfate can be leached through reduction leaching; under normal temperature and pressure, 9.4 grams of sulfur dioxide can be dissolved per 100ml of water; two-thirds Sulfur dioxide dissolved in water reacts with water to form sulfurous acid; sulfurous acid can be used as a reducing agent to convert pentavalent vanadium into tetravalent vanadium that is easily soluble in water; use a filter press to separate the reduction and leaching products to obtain acid leaching solution and leaching Slag I.

4. Separation of vanadium and potassium: Add the water immersion solution in step 2 and the acid immersion solution in step 4 into the FRP reactor, then slowly add 1mol/L KOH solution, adjust the pH to 7, and react at 60°C 90 minutes; the purpose of using KOH solution is not to introduce impurity ions before separating the potassium sulfate solution; use a filter press to separate the vanadium and potassium separation products to obtain potassium sulfate solution and filter cake I.

5. Alkali dissolution and impurity removal: Dissolve the filter cake I obtained in step 4 in potassium hydroxide solution, and adjust the pH to be greater than 13 and less than 14. When 13≤pH≤14, the pentavalent vanadium ion exists in the form of VO ₄ ^3- in water and is easily soluble in water. Then add the oxidant sodium chlorate and boil to make the solution change from blue to yellow; at this time, the tetravalent vanadium has been converted into pentavalent vanadium; use a filter press to separate the alkali-dissolved impurity removal products to obtain leaching residue II and filtrate I .

6. Adjust the pH: add the filtrate I obtained in step 5 into the glass fiber reinforced plastic reactor, then add hydrochloric acid solution dropwise, and adjust the pH to 8; obtain the leaching residue III and the filtrate II; adjust the pH value to 8 to facilitate the precipitation of ammonium metavanadate generate.

7. Precipitation of vanadium: add the filtrate II obtained by adjusting the pH to the reaction vessel, and then add ammonium chloride solution dropwise; react at room temperature for 90 minutes; separate the product of vanadium precipitation with a filter press to obtain ammonium metavanadate precipitation.

8. Roasting: put the precipitated ammonium metavanadate obtained in step 7 into a heating furnace for thermal decomposition, heat to 320°C, keep it warm for 2 hours, and then cool to room temperature with the furnace to obtain a V ₂ O ₅ solid with a purity greater than 97%; discharge The NH ₃ exhaust gas is absorbed by sulfuric acid solution to generate ammonium sulfate solution, which is returned to the vanadium precipitation process.

9. Concrete production: Grind the leaching slag I, leaching slag II, and leaching slag III and mix them evenly, then mix them with cement, medium sand, aggregate, and reinforcing fibers, then add admixtures and water, and stir for 4 minutes to obtain concrete.

The parts by mass of each component of the concrete are as follows: 300 parts of leaching slag, 300 parts of Portland cement with a strength index of 32.5; 600 parts of medium sand with a fineness modulus of 2.7, 600 parts of cinder, 20 parts of 20mm glass fiber, 10 parts of admixture, 210 parts of water.

The admixture consists of 35 parts of polycarboxylate water reducer, 6 parts of silane coupling agent, 3 parts of polyvinylpyrrolidone, 2 parts of silicon carbide, 8 parts of silicon dioxide coated titanium dioxide, 5 parts of gelatin powder, 12 parts of bentonite, It is made by mixing 10 parts of nano carbon powder, 4 parts of sodium gluconate and 4 parts of phenol acetate.

10. Potassium sulfate production: the potassium sulfate solution obtained in step 4 is transported to the concentrator for concentration, distilled water is concentrated to obtain a concentrated solution; the concentrated solution is sent to the crystallization kettle for cooling and crystallization, and potassium sulfate with a purity greater than 98% is obtained solid.

Example 3

A method for processing spent vanadium catalyst, comprising the steps of:

1. Grinding: Send the spent vanadium catalyst to a ball mill for grinding until the particle size is less than 125 microns; a particle size of 125 microns is 120 mesh.

2. Water leaching: Mix the ground waste vanadium catalyst with water evenly, with a solid-to-liquid weight ratio of 1:3; leaching at 80°C for 2 hours; leaching 30% of vanadium pentoxide and A mixture of vanadium tetroxide, 50% potassium sulfate. When 6≤pH≤8, pentavalent vanadium ions exist in the form of VO ₃ (OH) ^2- , V ₃ O ₉ ^3- , V ₄ O ₁₂ ^4- in water, and are hardly soluble in water. Vanadium tetroxide is easily soluble in water. The water leaching product is separated by a filter press to obtain a water immersion liquid and a water leaching residue; the water immersion liquid directly enters a vanadium and potassium separation process; and the water leaching residue enters a reduction leaching process.

3. Reduction leaching: Mix 1mol/L sulfuric acid solution and spent vanadium catalyst in a mass ratio of 5:1 to form a mixed solution, which is added to the enamel reaction kettle; 50% sulfur dioxide, reacted for 2 hours; sulfur dioxide tail gas was absorbed with sodium hydroxide solution; pH sensor, temperature sensor and pressure sensor were installed in the enamel reaction kettle; remaining vanadium oxide and potassium sulfate could be leached by reduction leaching; normal temperature Under normal pressure, 9.4 grams of sulfur dioxide can be dissolved per 100ml of water; two-thirds of the sulfur dioxide dissolved in water reacts with water to form sulfurous acid; sulfurous acid can be used as a reducing agent to convert pentavalent vanadium into tetravalent vanadium that is easily soluble in water ; Separating the reduction leaching product with a filter press to obtain acid leaching solution and leaching residue I;

4. Separation of vanadium and potassium: Add the water immersion solution in step 2 and the acid immersion solution in step 4 into the FRP reactor, then slowly add 1mol/L KOH solution, adjust the pH to 7, and react at 60°C 90 minutes; the purpose of using KOH solution is not to introduce impurity ions before the potassium sulfate solution is separated; the vanadium and potassium separation products are separated with a filter press to obtain potassium sulfate solution and filter cake I;

5. Alkali dissolution and impurity removal: Dissolve the filter cake I obtained in step 4 in an alkaline solution, and adjust the pH to be greater than 13 and less than 14. When 13≤pH≤14, the pentavalent vanadium ion exists in the form of VO ₄ ^3- in water and is easily soluble in water. Then add oxidant potassium chlorate and boil to make the solution change from blue to yellow; at this time, tetravalent vanadium has been converted into pentavalent vanadium; use a filter press to separate the alkali-dissolved impurity removal product to obtain leaching residue II and filtrate I;

6. Adjust the pH: Add the filtrate I obtained in step 5 into the glass fiber reinforced plastic reactor, then slowly add sulfuric acid solution, adjust the pH to 8; obtain the leaching residue III and the filtrate II; adjust the pH value to 8, which is conducive to the precipitation of ammonium metavanadate generate;

7. Precipitation of vanadium: add the filtrate II obtained by adjusting the pH to the reaction vessel, and then add ammonium chloride solution dropwise; react at room temperature for 90 minutes; use a filter press to separate the product of the precipitation of vanadium to obtain precipitation of ammonium metavanadate;

8. Roasting: put the precipitated ammonium metavanadate obtained in step 7 into a heating furnace for thermal decomposition, heat to 320°C, keep it warm for 2 hours, and then cool to room temperature with the furnace to obtain a V ₂ O ₅ solid with a purity greater than 97%; discharge The _NH3 exhaust gas is absorbed with sulfuric acid solution to generate ammonium sulfate solution, which is returned to the vanadium precipitation process;

9. Concrete production: Grind the leaching slag I, leaching slag II, and leaching slag III and mix them evenly, then mix them with cement, medium sand, aggregate, and reinforcing fibers, then add admixtures and water, and stir for 4 minutes to obtain concrete;

The mass parts of each component are as follows: 100 parts of leaching slag, 200 parts of Portland cement with a strength index of 42.5; 300 parts of medium sand with a fineness modulus of 2.7, a particle size of 20mm, and a powder content of 5.4%. 600 parts of stones with a fineness modulus of 1.8, 20 parts of 10mm carbon fiber, 5 parts of admixture, and 190 parts of water;

The admixture consists of 35 parts of polycarboxylate water reducer, 6 parts of silane coupling agent, 3 parts of polyvinylpyrrolidone, 2 parts of silicon carbide, 8 parts of silicon dioxide coated titanium dioxide, 5 parts of gelatin powder, 12 parts of bentonite, 10 parts of nano carbon powder, 4 parts of sodium gluconate, 4 parts of phenol acetate;

10. Potassium sulfate production: the potassium sulfate solution obtained in step 4 is transported to the concentrator for concentration, distilled water is concentrated to obtain a concentrated solution; the concentrated solution is sent to the crystallization kettle for cooling and crystallization, and potassium sulfate with a purity greater than 98% is obtained solid.

The above-mentioned embodiment is a preferred embodiment of the present invention, but the embodiment of the present invention is not limited by the above-mentioned embodiment, and any other changes, modifications, substitutions, combinations and modifications made without departing from the spirit and principles of the present invention Simplifications should be equivalent replacement methods, and all are included in the protection scope of the present invention.

Claims (10)

1. a method for processing spent vanadium catalyst, is characterized in that, comprises following concrete steps: S1. Grinding the spent vanadium catalyst into granules, adding water to mix evenly, immersing in water at a temperature of 30-100° C. for 0.5-4 hours, separating the water-leaching products to obtain water-leaching liquid and water-leaching residue; S2. Mix the acid solution and water leaching slag, react in an atmosphere of sulfur dioxide for 0.5 to 4 hours, and separate the product to obtain acid leaching solution and leaching slag I; S3. Mix the water immersion solution in step S1 with the acid immersion solution in step S2, add KOH solution dropwise, adjust the pH to 6-8, react at 40-80°C for 30-120min, separate the product to obtain potassium sulfate Solution and filter cake I; S4. Dissolving the filter cake I in the alkaline solution, adjusting the pH to 13-14, then adding an oxidizing agent, boiling to make the solution change from blue to yellow, and separating the product to obtain leaching residue II and filtrate I; S5. Add the acidic solution dropwise to the filtrate I, adjust the pH to 4.7-10, and obtain the leaching residue III and the filtrate II; S6. Add the ammonium salt solution or ammonia water dropwise to the filtrate II, adjust the pH to 8, react at room temperature for 30-90 minutes, separate the product, and obtain ammonium metavanadate precipitate; S7. Precipitating ammonium metavanadate is heated to 300-500° C. in air or oxygen, kept for 1-2 hours, and then cooled to room temperature with the furnace to obtain a V ₂ O ₅ solid with a purity greater than 97.5%. S8. Grind the leaching slag I, leaching slag II, and leaching slag III, mix them evenly, add them to the mixture of cement, medium sand, aggregate and reinforcing fiber and mix them, then add admixtures and water to mix, and stir for 2 to 4 minutes , to make concrete; S9. Concentrate the potassium sulfate solution obtained in step S3 and cool down to crystallize to obtain potassium sulfate. 2. The method for treating spent vanadium catalysts according to claim 1, characterized in that, the particle size of the particles in step S1 is 1-125 microns. 3. The method for treating spent vanadium catalysts according to claim 1, characterized in that the mass ratio of spent vanadium catalysts to water in step S1 is 1: (1.5-5). 4. The method for processing spent vanadium catalysts according to claim 1, characterized in that the mass ratio of the acidic solution and the water leaching residue in step S2 is (1.5～5):1, and the concentration of the sulfur dioxide is 5 ~99%. 5. The method for treating spent vanadium catalyst according to claim 1, characterized in that, the acidic solution in steps S2 and S5 is at least one of sulfuric acid, nitric acid, citric acid or hydrochloric acid. 6. the method for processing spent vanadium catalyst according to claim 1, is characterized in that, alkali solution described in step S4 is more than one in sodium hydroxide solution, potassium hydroxide solution or calcium hydroxide solution, and described The oxidizing agent is at least one of permanganate, sodium chlorate or hydrogen peroxide. 7. The method for processing spent vanadium catalyst according to claim 1, characterized in that, the ammonium salt solution described in step S6 is ammonium chloride, ammonium sulfate, ammonium bisulfate, ammonium nitrate, ammonium carbonate or ammonium bicarbonate more than one of . 8. The method for treating spent vanadium catalysts according to claim 1, characterized in that the components of the concrete in step S8 are as follows: 100-300 parts of leach slag, 200-300 parts of cement; 300-600 parts of medium sand , 600-1000 parts of aggregate, 10-20 parts of reinforcing fiber, 5-10 parts of admixture, 170-210 parts of water. 9. The method for treating spent vanadium catalyst according to claim 8, characterized in that, the admixture comprises 35 parts of polycarboxylate water reducer, 6 parts of silane coupling agent, 3 parts of polyvinylpyrrolidone, silicon carbide 2 parts, 8 parts of silica-coated titanium dioxide, 5 parts of gelatin powder, 12 parts of bentonite, 10 parts of nano carbon powder, 4 parts of sodium gluconate and 4 parts of phenol acetate. 10. The method for processing spent vanadium catalyst according to claim 8, characterized in that, the fineness modulus of the medium sand is 2.3 to 3, the aggregate is cinder, slag, blast furnace slag or stone, and the The particle size of the aggregate is 10-20mm; the fineness modulus of the aggregate is 1.6-1.8; the cement is Portland cement, and the strength index of the Portland cement is 32.5 or 42.5; the strengthening The fiber is more than one of steel fiber, glass fiber or carbon fiber, and the length of the reinforcing fiber is 9-30 mm.