Method for recycling hazardous waste waste SCR catalyst and efficiently separating valuable components

Abstract

The invention belongs to the technical field of waste catalyst recycling, and particularly discloses a hazardous waste waste SCR catalyst recycling treatment and valuable component efficient separation method which comprises the following steps that firstly, waste SCR catalysts are crushed, screened and roasted; after cooling, adding a leaching agent, heating and stirring to obtain a leaching solution and leaching residues; then adding ammonia water into the impurity-removed leachate to leach vanadium; oxalic acid is added into the leachate, so that tungsten is leached; then, a leaching agent is added into the leaching residues, stirring and filtering are conducted, and secondary leaching liquid containing titanium and leaching tailings are obtained; precipitating and filtering titanium in the secondary leaching solution; and finally, the tailings are washed and dried. According to the method, the leaching agent and the precipitating agent are added into the waste SCR catalyst, and valuable metals in the waste SCR catalyst are reasonably recycled, so that the valuable metals in the waste SCR catalyst are efficiently recycled, and the problems of resource waste and environmental pollution caused by landfill incineration of the waste SCR catalyst are solved.

Description

Technical Field

[0001] The invention relates to the technical field of waste catalyst recycling, and in particular to a method for resource disposal of hazardous waste waste SCR catalyst and efficient separation of valuable components. Background Art

[0002] SCR catalyst is a catalyst specially used to reduce nitrogen oxide emissions. The main working principle of SCR catalyst is to selectively convert nitrogen oxides in flue gas into harmless nitrogen and water by adding a reducing agent such as ammonia, ammonia water or urea under certain temperature conditions without reacting with oxygen in the flue gas. The chemical reaction formula is: 4NH 3 +6NO=5N 2 +6H 2 O,8NH 3 +6NO 2 =7N 2 +12H 2 O. SCR technology is widely used in various industrial fields, including power plants, filtration, waste incineration plants and motor vehicle exhaust treatment systems.

[0003] Selective catalytic reduction technology is currently an important means of denitrification of industrial waste gas. However, after long-term use, SCR catalysts will be deactivated due to poisoning, wear and other reasons, and become waste SCR catalysts. These waste SCR catalysts contain a large amount of valuable metals, such as vanadium, tungsten, titanium, etc. If they are not properly recycled and utilized, it will cause a waste of resources; currently, the treatment of waste SCR catalysts is usually to atomize and crush the waste SCR catalysts, collect them in a high-temperature garbage incinerator for combustion treatment; or crush and pack the waste SCR catalysts, and select a deeper area in the landfill to compress and cover the waste SCR catalysts. The use of incineration and landfill to treat waste SCR catalysts will not only cause waste of resources but also pollute the environment.

[0004] Therefore, in order to solve the above problems, it is necessary to design a method for resource disposal of hazardous waste waste SCR catalysts and efficient separation of valuable components, to achieve efficient recovery of valuable metals in waste SCR catalysts, and to reasonably treat the leached residues, further realize the comprehensive utilization of resources, reduce waste emissions, and reduce the impact of waste SCR catalysts on the environment. Summary of the invention

[0005] The purpose of the present invention is to provide a method for resource disposal of hazardous waste waste SCR catalyst and efficient separation of valuable components, so as to solve the problem that landfill and incineration of waste SCR catalyst will not only cause waste of resources but also pollute the environment.

[0006] To achieve the above-mentioned purpose, the basic scheme provided by the present invention is: a method for resource disposal of hazardous waste SCR catalyst and efficient separation of valuable components, comprising the following steps:

[0007] S1: crushing and screening the waste SCR catalyst, and then calcining the screened waste SCR catalyst;

[0008] S2: Cool the calcined waste SCR catalyst, add a leaching agent to the waste SCR catalyst after cooling, heat to 60°C-80°C, stir for 3-5 hours at a stirring speed of 200r / min-300r / min, and then filter the liquid to obtain a primary leaching solution and a primary leaching residue containing valuable metals;

[0009] S3: adding ammonia water to the primary leachate in small amounts and multiple times, adjusting the pH value of the primary leachate to 2-3, precipitating impurities such as iron and aluminum in the primary leachate, and then filtering out the precipitate in the primary leachate;

[0010] S4: adding ammonia water in small amounts and multiple times to the primary leachate after impurities are removed, adjusting the pH value of the primary leachate to 8-9, so that the vanadium in the primary leachate is precipitated in the form of ammonium metavanadate, and filtering the liquid in the primary leachate after precipitation for 10-20 minutes;

[0011] S5: adding an appropriate amount of oxalic acid to the primary leaching solution after vanadium extraction to precipitate tungsten in the primary leaching solution in the form of tungsten oxalate. After precipitation for 20-30 minutes, filtering the liquid in the primary leaching solution to which oxalic acid has been added;

[0012] S6: adding a leaching agent to the primary leaching residue in S2, heating the primary leaching residue with the leaching agent to 80°C-100°C and performing secondary stirring for 3-5 hours at a stirring speed of 300r / min-500r / min, and then filtering the liquid in the primary leaching residue to obtain a secondary leaching solution and leaching tailings containing titanium;

[0013] S7: adding a precipitant to the secondary leaching solution containing titanium to precipitate the titanium in the secondary leaching solution in the form of titanium oxalate, and filtering the liquid in the secondary leaching solution after precipitation for 20-30 minutes;

[0014] S8: Wash the leached tailings with water and dry them.

[0015] The beneficial effects of the present invention are as follows: (1) the present invention realizes the recovery of valuable metals in the waste SCR catalyst by crushing and roasting the waste SCR and then adding a leaching agent to separate the valuable metals, thereby improving resource utilization, and also treating the tailings to prevent secondary pollution to the environment; (2) the leaching agent used for leaching the valuable metals in the present invention is relatively mild and less corrosive to the equipment, thereby reducing the investment cost and maintenance cost of the equipment; (3) the leaching residue is reasonably treated to realize the comprehensive utilization of resources, reduce the discharge of waste, and thus reduce the impact on the environment.

[0016] Scheme 2 is the preferred basic scheme. In S1, the particle size of the waste SCR catalyst after crushing is 3mm-5mm, the calcination temperature of the waste SCR catalyst is 600℃-800℃, and the calcination time of the waste SCR catalyst is 6-8 hours; the small particles of the waste SCR catalyst after crushing are more uniform, which improves the activity of the catalyst and can also make the waste SCR catalyst more evenly distributed in the reactor, ensuring that the reaction effect in the entire reaction vessel is more consistent, and the crushed particles can be more fully in contact with the leaching agent, making the resource recovery treatment more thorough; crushing the waste SCR catalyst and then calcining it can remove organic matter and other volatile impurities on the surface.

[0017] Scheme 3 is a preferred basic scheme. In S2, the waste SCR catalyst and the leaching agent are mixed at a ratio of 1:3-1:5, the leaching agent is a mixed solution of sulfuric acid and hydrogen peroxide, the sulfuric acid concentration is 1 mol / L-3 mol / L, and the volume fraction of hydrogen peroxide is 8%-10%; using the mixed solution of sulfuric acid and hydrogen peroxide as the leaching agent, the leaching efficiency is better.

[0018] Scheme 4 is a preferred option of the basic scheme. In S4, the filtered ammonium metavanadate is calcined at 600°C-1000°C for 5-8 hours to obtain a vanadium pentoxide product.

[0019] Scheme 5 is the preferred option of the basic scheme. In S5, the filtered tungsten oxalate is calcined at 800°C-1000°C for 6-8 hours to obtain tungsten trioxide product.

[0020] Scheme six is ​​the preferred basic scheme. In S6, the primary leaching residue and the leaching agent are mixed at a ratio of 1:3-1:5, the leaching agent is a mixed solution of hydrochloric acid and hydrofluoric acid, the concentration of the hydrochloric acid is 1mol / L-3mol / L, and the volume fraction of the hydrofluoric acid is 8%-10%; the mixed solution of hydrochloric acid and hydrofluoric acid is used as the leaching agent for leaching titanium, and the leaching effect is good.

[0021] Scheme 7 is a preferred option of the basic scheme. In S7, the filtered titanium oxalate precipitate is calcined at 800° C.-1000° C. for 5-8 hours to obtain a titanium dioxide product.

[0022] Scheme 8 is a preferred option of the basic scheme. In S8, the drying temperature of the leached tailings is 100°C-120°C, and the drying time is 2-4 hours. After the leached tailings are washed and dried, they can be used as additives for building materials or other industrial raw materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a process flow chart of a method for resource disposal of hazardous waste SCR catalyst and efficient separation of valuable components of the present invention. DETAILED DESCRIPTION

[0024] The present invention is further described in detail below through specific embodiments:

[0025] Example 1

[0026] A method for resource disposal of hazardous waste SCR catalyst and efficient separation of valuable components, such as Figure 1 The following steps are shown:

[0027] S1: When starting to separate the valuable components in the waste SCR catalyst, the waste SCR catalyst is first crushed, and the particle size of the waste SCR catalyst after crushing is 3mm-5mm, and then the crushed waste SCR catalyst is screened to remove impurities and large particle agglomerates, and then the screened waste SCR catalyst is calcined at 600℃-800℃ for 6-8 hours;

[0028] S2: then cooling the calcined waste SCR catalyst, adding a leaching agent to the waste SCR catalyst after cooling, the ratio of the waste SCR catalyst to the leaching agent is 1:3-1:5, the leaching agent is a mixed solution of sulfuric acid and hydrogen peroxide, wherein the concentration of sulfuric acid is 1mol / L-3mol / L, and the volume fraction of hydrogen peroxide is 8%-10%, then heating the waste SCR catalyst with the leaching agent to 60°C-80°C, stirring for 3-5 hours, and the stirring speed is 200r / min-300r / min, and then filtering to obtain a primary leaching solution and a primary leaching residue containing valuable metals;

[0029] S3: then adding ammonia water to the primary leachate in small amounts and multiple times, adjusting the pH value of the primary leachate to 2-3, so that the iron and aluminum impurities in the primary leachate are precipitated, and then filtering out the precipitate in the primary leachate;

[0030] S4: adding ammonia water in small amounts to the primary leaching solution after removing impurities for multiple times, adjusting the pH value of the primary leaching solution to 8-9, so that the vanadium in the primary leaching solution is precipitated in the form of ammonium metavanadate, filtering after precipitation for 10-20 minutes, and then calcining the filtered ammonium metavanadate at 600° C.-1000° C. for 5-8 hours to obtain a vanadium pentoxide product;

[0031] S5: Add an appropriate amount of oxalic acid to the primary leaching solution after vanadium extraction to precipitate the tungsten in the primary leaching solution in the form of tungsten oxalate. After precipitation for 20-30 minutes, filter it; then calcine the filtered tungsten oxalate at 800℃-1000℃ for 6-8 hours to obtain tungsten trioxide product;

[0032] S6: then adding a leaching agent to the primary leaching residue in S2, the ratio of the primary leaching residue to the leaching agent is 1:3-1:5, the leaching agent is a mixed solution of hydrochloric acid and hydrofluoric acid, the concentration of hydrochloric acid is 1mol / L-3mol / L, and the volume fraction of hydrofluoric acid is 8%-10%, then heating the primary leaching residue with the leaching agent to 80°C-100°C, stirring for 3-5 hours, the stirring speed is 300r / min-500r / min, and then filtering to obtain a secondary leaching solution and leaching tailings containing titanium;

[0033] S7: then adding a precipitant to the secondary leachate containing titanium, the precipitant being oxalic acid, so that the titanium in the secondary leachate is precipitated in the form of titanium oxalate, and filtering after precipitation for 20-30 minutes; then calcining the filtered titanium oxalate at 800° C.-1000° C. for 5-8 hours to obtain a titanium dioxide product;

[0034] S8: Finally, the leached tailings are washed with water and then dried at 100°C-120°C for 2-4 hours.

[0035] The valuable metals in the waste SCR catalyst are leached by the above method, and the leaching rates of vanadium and tungsten in the waste SCR catalyst can reach more than 93%. A mixed solution of hydrochloric acid and hydrofluoric acid is used as a leaching agent for leaching titanium, and finally the leaching rate of titanium in the waste SCR catalyst can reach more than 98%.

[0036] Example 2

[0037] A method for resource disposal of hazardous waste SCR catalyst and efficient separation of valuable components, such as Figure 1 The following steps are shown:

[0038] S1: When starting to separate the valuable components in the waste SCR catalyst, the waste SCR catalyst is first crushed, and the particle size of the waste SCR catalyst after crushing is 3mm-5mm, and then the crushed waste SCR catalyst is screened to remove impurities and large particle agglomerates, and then the screened waste SCR catalyst is calcined at 600℃-800℃ for 6-8 hours;

[0039] S2: then cooling the calcined waste SCR catalyst, adding a leaching agent to the waste SCR catalyst after complete cooling, the ratio of the waste SCR catalyst to the leaching agent is 1:1-1:2, the leaching agent is a mixed solution of sulfuric acid and hydrogen peroxide, wherein the concentration of sulfuric acid is 1 mol / L, and the volume fraction of hydrogen peroxide is 6%, then heating the waste SCR catalyst with the leaching agent to 80°C, stirring for 3 hours at a stirring speed of 200 r / min, and then filtering to obtain a primary leaching solution and a primary leaching residue containing valuable metals;

[0040] S3: then adding ammonia water to the primary leachate in small amounts and multiple times, adjusting the pH value of the primary leachate to 2-3, so that impurities such as iron and aluminum in the primary leachate are precipitated, and then filtering out the precipitate in the primary leachate;

[0041] S4: adding ammonia water in small amounts to the primary leaching solution after removing impurities for multiple times, adjusting the pH value of the primary leaching solution to 8-9, so that the vanadium in the primary leaching solution is precipitated in the form of ammonium metavanadate, filtering after precipitation for 10-20 minutes, and then calcining the filtered ammonium metavanadate at 600° C.-1000° C. for 5-8 hours to obtain a vanadium pentoxide product;

[0042] S5: Add an appropriate amount of oxalic acid to the primary leaching solution after vanadium extraction to precipitate the tungsten in the primary leaching solution in the form of tungsten oxalate, and filter it after precipitation for 20-30 minutes; then calcine the filtered tungsten oxalate precipitate at 800℃-1000℃ for 6-8 hours to obtain tungsten trioxide product;

[0043] S6: then adding a leaching agent to the primary leaching residue in S2, the ratio of the primary leaching residue to the leaching agent is 1:1-1:2, the leaching agent is a mixed solution of hydrochloric acid and hydrofluoric acid, the concentration of hydrochloric acid is 1 mol / L, and the volume fraction of hydrofluoric acid is 6%, then heating the primary leaching residue with the leaching agent to 80°C, stirring for 3 hours at a stirring speed of 200 r / min, and then filtering to obtain a secondary leaching solution and leaching tailings containing titanium;

[0044] S7: then adding a precipitant to the secondary leachate containing titanium, the precipitant being oxalic acid, so that the titanium in the secondary leachate is precipitated in the form of titanium oxalate, and filtering after precipitation for 20-30 minutes; then calcining the filtered titanium oxalate at 800° C.-1000° C. for 5-8 hours to obtain a titanium dioxide product;

[0045] S8: Finally, the leached tailings are washed with water and then dried at 100°C-120°C for 2-4 hours.

[0046] By leaching the valuable metals in the waste SCR catalyst according to Example 2, the leaching rate of vanadium in the waste SCR catalyst can reach about 74%, the leaching rate of tungsten can reach about 67%, and the leaching rate of titanium can reach about 80%.

[0047] In summary, both Example 1 and Example 2 can separate the valuable metals in the waste SCR catalyst, but the leaching rates of vanadium and tungsten in Example 1 can reach more than 93%, which is higher than the leaching rates of vanadium and tungsten in Example 2, and the leaching rate of titanium can reach more than 98%, which is higher than the leaching rate of titanium in Example 2; the valuable metals in the waste SCR catalyst are separated by the method in Example 1, thereby improving the resource utilization rate.

[0048] The above is only an embodiment of the present invention, and the common knowledge such as the known specific structure and characteristics in the scheme is not described in detail here. It should be pointed out that for those skilled in the art, several deformations and improvements can be made without departing from the structure of the present invention, which should also be regarded as the protection scope of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. A method for resource disposal of hazardous waste SCR catalyst and efficient separation of valuable components, characterized in that: The following steps are involved: S1: crushing and screening the waste SCR catalyst, and then calcining the screened waste SCR catalyst; S2: Cool the calcined waste SCR catalyst, add a leaching agent to the waste SCR catalyst after cooling, heat to 60°C-80°C, stir for 3-5 hours at a stirring speed of 200r / min-300r / min, and then filter the liquid to obtain a primary leaching solution and a primary leaching residue containing valuable metals; S3: adding ammonia water to the primary leachate in small amounts for multiple times, adjusting the pH value of the primary leachate to 2-3, precipitating impurities in the primary leachate, and then filtering out the precipitate in the primary leachate; S4: adding ammonia water in small amounts and multiple times to the primary leachate after impurities are removed, adjusting the pH value of the primary leachate to 8-9, so that the vanadium in the primary leachate is precipitated in the form of ammonium metavanadate, and filtering the liquid in the primary leachate after precipitation for 10-20 minutes; S5: adding an appropriate amount of oxalic acid to the primary leaching solution after vanadium extraction to precipitate tungsten in the primary leaching solution in the form of tungsten oxalate. After precipitation for 20-30 minutes, filtering the liquid in the primary leaching solution to which oxalic acid has been added; S6: adding a leaching agent to the primary leaching residue in S2, heating the primary leaching residue with the leaching agent to 80°C-100°C and performing secondary stirring for 3-5 hours at a stirring speed of 300r / min-500r / min, and then filtering the liquid in the primary leaching residue to obtain a secondary leaching solution and leaching tailings containing titanium; S7: adding a precipitant to the secondary leaching solution containing titanium to precipitate the titanium in the secondary leaching solution in the form of titanium oxalate, and filtering the liquid in the secondary leaching solution after precipitation for 20-30 minutes; S8: Wash the leached tailings with water and dry them.

2. The method for resource disposal of hazardous waste SCR catalyst and efficient separation of valuable components according to claim 1 is characterized in that: In S1, the particle size of the waste SCR catalyst after crushing is 3mm-5mm, the calcination temperature of the waste SCR catalyst is 600°C-800°C, and the calcination time of the waste SCR catalyst is 6-8 hours.

3. The method for resource disposal of hazardous waste SCR catalyst and efficient separation of valuable components according to claim 1 is characterized in that: In S2, the waste SCR catalyst and the leaching agent are mixed at a ratio of 1:3-1:5, the leaching agent is a mixed solution of sulfuric acid and hydrogen peroxide, the concentration of the sulfuric acid is 1 mol / L-3 mol / L, and the volume fraction of the hydrogen peroxide is 8%-10%.

4. The method for resource disposal of hazardous waste SCR catalyst and efficient separation of valuable components according to claim 1 is characterized in that: In S4, the filtered ammonium metavanadate is calcined at 600°C-1000°C for 5-8 hours to obtain a vanadium pentoxide product.

5. The method for resource disposal of hazardous waste SCR catalyst and efficient separation of valuable components according to claim 1 is characterized in that: In S5, the filtered tungsten oxalate is calcined at 800°C-1000°C for 6-8 hours to obtain a tungsten trioxide product.

6. The method for resource disposal of hazardous waste SCR catalyst and efficient separation of valuable components according to claim 1 is characterized in that: In S6, the primary leaching residue and the leaching agent are mixed at a ratio of 1:3-1:5, the leaching agent is a mixed solution of hydrochloric acid and hydrofluoric acid, the concentration of the hydrochloric acid is 1 mol / L-3 mol / L, and the volume fraction of the hydrofluoric acid is 8%-10%.

7. The method for resource disposal of hazardous waste SCR catalyst and efficient separation of valuable components according to claim 1 is characterized in that: In S7, the precipitant is oxalic acid, and the filtered titanium oxalate is calcined at 800° C.-1000° C. for 5-8 hours to obtain a titanium dioxide product.

8. The method for resource disposal of hazardous waste SCR catalyst and efficient separation of valuable components according to claim 1 is characterized in that: In S8, the drying temperature of the leaching tailings is 100°C-120°C, and the drying time is 2-4 hours.

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