Method for in-situ regeneration and Tl resource recovery of Tl-poisoned SCR (Selective Catalytic Reduction) catalyst

Abstract

The invention provides a Tl poisoning SCR catalyst in-situ regeneration and Tl resource recovery method, and belongs to the field of waste SCR catalyst recovery. The method comprises the following steps: putting a Tl-poisoned SCR catalyst into a glycine solution, and carrying out solid-liquid separation to obtain a thallium leaching solution and a regenerated SCR catalyst; and then, carrying out thallium precipitation treatment on the thallium leachate, and carrying out solid-liquid separation to obtain thallium-containing precipitates. According to the method, the Tl is selectively extracted from the catalyst by utilizing the specific coordination effect of the glycine and the Tl, and the extracted Tl is recovered while the activity of the SCR catalyst is recovered, so that waste recycling is realized, and the environmental risk is reduced.

Description

Technical Field

[0001] The present invention relates to the field of waste SCR catalyst recovery, and in particular to a method for in-situ regeneration of a Tl-poisoned SCR catalyst and Tl resource recovery. Background Art

[0002] Selective catalytic reduction (SCR) denitrification is the most mature and reliable NO x Control technology. Commercial V2O5-WO3 / TiO2 catalysts have been widely used in thermal power, coking, cement, glass, steel and other industries. The service life of V / W-Ti catalysts (SCR catalysts) is generally 2-3 years, after which they are scrapped due to deactivation. However, V2O5-WO3 / TiO2 catalysts are expensive ($3500-4000 / ton) and are classified as hazardous waste, which has also attracted environmental protection concerns. Therefore, there is an urgent need to develop effective methods to properly dispose of these spent catalysts and reuse them as resources.

[0003] Chemical poisoning has long been considered a key factor in the deactivation of V2O5-WO3 / TiO2 catalysts. Various harmful elements present in industrial raw materials and fuels enter the flue gas in the form of oxides, chlorides, and sulfates under high-temperature conditions, poisoning the V2O5-WO3 / TiO2 catalyst. Elements such as K, Na, Ca, As, Pb, Hg, and P are important poisoning elements. In recent years, a newly discovered toxic element, Tl, has been detected in spent V / W-Ti catalysts, leading to severe catalyst deactivation. Furthermore, Tl is one of the most biotoxic heavy metals, exceeding its toxicity to humans, exceeding that of Pb, Hg, Cd, Cu, or Zn. However, research on the regeneration of Tl-poisoned catalysts remains limited. Traditional acid and alkaline leaching methods suffer from high vanadium loss, low activity recovery, high cost, and difficulty in industrialization. Therefore, the regeneration of Tl-poisoned catalysts remains a challenging task, necessitating the development of a regeneration agent with a specific affinity for Tl.

[0004] In view of this, it is necessary to provide a method for in-situ regeneration of a Tl-poisoned SCR catalyst and Tl resource recovery to solve or at least alleviate the technical problem of how to effectively restore the activity of the SCR catalyst and efficiently extract Tl. Summary of the Invention

[0005] The main purpose of the present invention is to provide a method for in-situ regeneration of a Tl-poisoned SCR catalyst and Tl resource recovery, aiming to solve the above-mentioned technical problems of how to effectively restore the activity of the SCR catalyst and efficiently extract Tl.

[0006] To achieve the above object, the present invention provides a method for in-situ regeneration of a Tl-poisoned SCR catalyst, comprising: placing the Tl-poisoned SCR catalyst in a glycine solution, and obtaining a thallium leachate and a regenerated SCR catalyst after solid-liquid separation.

[0007] Furthermore, in the Tl-poisoned SCR catalyst, the mass proportion of the Tl element is 1-5%, and the mass proportion of the V element is 0.5-1%; in the Tl-poisoned SCR catalyst, the mass proportion of the Pb element is 0.005-0.02%, and the mass proportion of the K element is 0.1-0.2%.

[0008] Furthermore, the process of placing the Tl-poisoned SCR catalyst in a glycine solution includes: soaking the Tl-poisoned SCR catalyst in the glycine solution; the concentration of the glycine solution is 0.1-1 mol / L; the pH of the glycine solution is less than 2; the soaking is carried out at a temperature of 20-95°C; the soaking time is 5-15h; and the soaking is carried out under stirring conditions.

[0009] Furthermore, the concentration of the glycine solution is 0.3-0.7 mol / L; the pH of the glycine solution is 0.5-1.5; the soaking is performed at a temperature of 65-95° C.; and the soaking time is 8-13 h.

[0010] Furthermore, the soaking is carried out at a temperature of 65-75° C. and the soaking time is 11-13 hours.

[0011] Furthermore, the Tl poisoned SCR catalyst is placed in the glycine solution in the form of a sheet; the mass volume ratio of the Tl poisoned SCR catalyst to the glycine solution is 1g:10-50mL.

[0012] The present invention also provides a method for recovering Tl resources, comprising: obtaining the thallium leachate by adopting any of the above-described methods for in-situ regeneration of a Tl-poisoned SCR catalyst; then, subjecting the thallium leachate to a thallium precipitation treatment, and obtaining a thallium-containing precipitate after solid-liquid separation.

[0013] Furthermore, the thallium precipitation treatment includes: adding chloride salt to the unconcentrated thallium leachate for aging; or adding chloride salt to the concentrated thallium leachate for aging.

[0014] Furthermore, the aging is carried out at a temperature of 2-8° C.; the concentration of the chloride salt in the thallium leaching solution is 10-50 g / L; and the aging time is 6-15 hours.

[0015] Furthermore, the chloride salt includes one or more of KCl, NaCl, and MgCl2.

[0016] Compared with the prior art, the present invention has at least the following advantages:

[0017] This invention effectively restores the activity of SCR catalysts and efficiently extracts Tl. Addressing current regeneration technologies, which suffer from issues such as the lack of selective separation of poisoning metals, significant loss of active components, and high secondary molding costs for powder regeneration, this invention provides a method for in-situ regeneration of Tl-poisoned SCR catalysts and Tl resource recovery. By leveraging coordination regulation, the invention selectively separates poisoning elements from deactivated spent SCR catalysts through the specific coordination of glycine with Tl, while effectively retaining the active component V in the catalyst. The activity of the regenerated SCR catalyst reaches that of fresh catalyst, and Tl is precipitated with chloride salts, enabling Tl resource recovery. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0019] Figure 1 In the analysis example 1 of the present invention, the glycine solution (corresponding to the glycine in the figure) and the leachate (corresponding to the glycine-Tl in the figure) + )’s infrared spectrum;

[0020] Figure 2 In the analysis example 1 of the present invention, the glycine solution (corresponding to the glycine in the figure) and the leachate (corresponding to the glycine-Tl in the figure) + )’s Raman spectrum;

[0021] Figure 3 The NO of fresh V2O5-WO3 / TiO2 catalyst (corresponding to fresh in the figure), spent SCR catalyst (corresponding to poisoned in the figure) and regenerated catalyst (corresponding to regenerated in the figure) in the analysis example 2 of the present invention is shown in FIG. x Conversion rate, the activity of the regenerated catalyst is similar to that of the fresh catalyst;

[0022] Figure 4 This is the XRD pattern of the precipitated sample in Example 19 of the present invention, which realizes the recovery of Tl resources.

[0023] The realization of the objectives, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0024] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0025] Moreover, the technical solutions between the various embodiments of the present invention may be combined with each other, but this must be based on the fact that ordinary technicians in this field can implement them. When the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0026] When numerical ranges are given in the examples, it should be understood that unless otherwise specified herein, both endpoints of each numerical range and any value between the two endpoints may be used. Unless otherwise defined, all technical and scientific terms used herein are consistent with the prior art as understood by those skilled in the art and the description of the present invention. Any prior art methods, devices, and materials similar or equivalent to those described in the examples of the present invention may also be used to implement the present invention.

[0027] In the Examples, Comparative Examples, and Analytical Examples of the present invention, the spent SCR catalyst is a Tl-poisoned V2O5-WO3 / TiO2 catalyst, where the Tl in the spent SCR catalyst (Tl-poisoned SCR catalyst) is monovalent thallium. The dimensions of the intact sheet of spent SCR catalyst are 2 cm x 1 cm. Immersion is performed with stirring at 600 rpm. The drying temperature is 60°C for 12 hours. Aging is understood as standing. In Examples 1-8 of the present invention, a sulfuric acid solution is used to adjust the pH.

[0028] In the present invention, V retention rate = V content in the catalyst after leaching / (V content in the catalyst after leaching + V content in the leachate); the activity recovery rate is calculated as follows: activity recovery rate = regenerated catalyst NO x Conversion rate / fresh catalyst NO x Conversion rate (under the same conditions).

[0029] The invention provides a method for in-situ regeneration of a Tl-poisoned SCR catalyst, comprising: placing the Tl-poisoned SCR catalyst in a glycine solution, and obtaining a thallium leaching solution and a regenerated SCR catalyst after solid-liquid separation.

[0030] In the Tl-poisoned SCR catalyst of the present invention, the mass proportion of the Tl element is 1-5%, and the mass proportion of the V element is 0.5-1%; in the Tl-poisoned SCR catalyst, the mass proportion of the Pb element is 0.005-0.02%, and the mass proportion of the K element is 0.1-0.2%.

[0031] In the present invention, the SCR catalyst may include a V2O5-WO3 / TiO2 catalyst; the Tl in the Tl-poisoned SCR catalyst is monovalent thallium; the Tl-poisoned SCR catalyst may be derived from thermal power, steel, coking, cement, glass, ceramics and other industries.

[0032] In the present invention, the process of placing the Tl-poisoned SCR catalyst in the glycine solution includes: soaking the Tl-poisoned SCR catalyst in the glycine solution; the soaking can be performed under stirring conditions.

[0033] In the present invention, the soaking is carried out at a temperature of 20-95°C; further, the soaking is carried out at a temperature of 60-80°C or 70-90°C or 65-95°C; further, the soaking is carried out at a temperature of 65-75°C or 68-75°C; the soaking time is 5-15h; further, the soaking time is 8-14h or 8-13h; further, the soaking time is 11-13h, or 11.5-12.5h.

[0034] In the present invention, the concentration of the glycine solution is 0.1-1 mol / L; further, the concentration of the glycine solution is 0.3-0.7 mol / L; the pH of the glycine solution is less than 2; further, the pH of the glycine solution is 0.5-1.5 or 0.8-1.2.

[0035] In the present invention, the Tl-poisoned SCR catalyst is placed in the glycine solution in the form of a sheet; the size of the Tl-poisoned SCR catalyst sheet is 2 cm x 1 cm. In the specific operation, the spent SCR catalyst (Tl-poisoned SCR catalyst) is cut into complete sheets and then immersed in the glycine solution.

[0036] In the present invention, the mass volume ratio of the Tl poisoned SCR catalyst to the glycine solution may be 1 g:10-50 mL, further 1 g:10-30 mL.

[0037] The present invention also provides a method for recovering Tl resources, comprising: obtaining the thallium leachate by adopting any of the above-described methods for in-situ regeneration of a Tl-poisoned SCR catalyst; then, subjecting the thallium leachate to a thallium precipitation treatment, and obtaining a thallium-containing precipitate after solid-liquid separation, wherein the thallium-containing precipitate contains TlCl.

[0038] As an explanation of the thallium precipitation treatment, the thallium precipitation treatment includes: adding chloride salt to the unconcentrated thallium leachate for aging; or, adding chloride salt to the concentrated thallium leachate for aging; in the concentrated thallium leachate, the thallium concentration may be not less than 1500 mg / L or not less than 1800 mg / L, or may be 1600-2000 mg / L; of course, when chloride salt is added to the unconcentrated thallium leachate for aging, the thallium concentration of the thallium leachate when not concentrated can also be controlled to the above-mentioned thallium concentration after concentration.

[0039] Adding chloride salt to the unconcentrated thallium leachate for aging is: directly adding the chloride salt to the thallium leachate for aging; adding chloride salt to the concentrated thallium leachate for aging is: after concentrating the thallium leachate, adding chloride salt to the thallium leachate for aging.

[0040] In the present invention, the aging is preferably carried out at a temperature of 2-8°C or 4-6°C; the concentration of the chloride salt in the thallium leachate is 10-50g / L, further 15-40g / L or 25-40g / L or 25-30g / L; the aging time is 6-15h, further 7-13h or 8-12h or 7-9h.

[0041] In the present invention, the chloride salt includes one or more of KCl, NaCl, and MgCl2.

[0042] In the present invention, the -COOH of glycine has a specific coordination effect with Tl, and H + The introduction of can strengthen this coordination effect. The present invention avoids the simultaneous extraction of poisoning metals and active ingredient V, can selectively separate poisoning metals, and can effectively restore the activity of the catalyst. Specifically, the present invention addresses the problems of current regeneration technology such as the non-selective separation of poisoning metals, large loss of active ingredients, and high cost of secondary molding for powder regeneration, and provides a method for in-situ regeneration of Tl-poisoned SCR catalysts and Tl resource recovery; the present invention soaks the complete sheet-like waste SCR catalyst in a glycine solution for a period of time, extracts Tl from the catalyst through the specific coordination effect of glycine and Tl, and simultaneously realizes the regeneration of the catalyst; then recovers TlCl from the leachate by chloride salt precipitation.

[0043] The following are specific examples of the present invention:

[0044] Analysis example 1

[0045] 1. Comparison of regeneration agents:

[0046] The spent SCR catalyst was placed in the test liquid in the form of powder at a mass volume ratio of 1 g: 5 mL and soaked at 25°C for 12 h. The leachate and leach residue were obtained after solid-liquid separation.

[0047] In the spent SCR catalyst used in this analysis example, the mass fraction of Tl was 2.73%, the mass fraction of V was 0.84%, the mass fraction of Pb was 0.01%, and the mass fraction of K was 0.14%. The subsequent examples, comparative examples, and analysis examples all utilized spent SCR catalysts from the same batch as this analysis example, and the results were analyzed based on the elemental contents described in this analysis example.

[0048] In this analysis example, the test solutions are: 0.5 mol / L glycine solution, 0.5 mol / L acetic acid solution, and 0.5 mol / L malic acid solution.

[0049] In this analysis example, when a 0.5 mol / L glycine solution was used, the Tl extraction rate was 50.58% and the V retention rate was 99.7%.

[0050] In this analysis example, when a 0.5 mol / L acetic acid solution was used, the Tl extraction rate was 18.73% and the V retention rate was 99.5%.

[0051] In this analysis example, when a 0.5 mol / L malic acid solution was used, the Tl extraction rate was 44.65% and the V retention rate was 88.03%.

[0052] 2. Analysis of the binding of glycine and thallium:

[0053] like Figure 1 As shown, 1331cm -1 、1411cm -1 、1507cm -1 and 1603cm -1 They belong to CH2 swing, COO - Symmetric stretching, NH3 symmetric stretching and COO - Asymmetric stretching. Among them, the slight red shift of the COO- characteristic peak indicates that Tl + Coordinates with -COOH.

[0054] like Figure 2 As shown, 1639cm -1 、1556cm -1 、1449cm -1 、1415cm -1 、1333cm -1 and 1111cm -1 The peaks at - Asymmetric stretching, C=O vibration, CH2 bending, COO- Symmetric stretching, CH2 rocking, and NH3 + The shift of the C=O vibration peak indicates that Tl+ preferentially coordinates at the C=O site of the carboxyl group.

[0055] Example 1

[0056] The complete flaky spent SCR catalyst was placed in a 0.5 mol / L, pH=1 glycine solution at a mass volume ratio of 1 g:20 mL and soaked at 60°C for 12 h. The catalyst was then removed and the leachate was retained. The catalyst was washed with deionized water and dried to obtain a regenerated catalyst.

[0057] In this embodiment, the Tl extraction rate is 80.4%, the V retention rate is 76.12%, and the activity recovery rate of the regenerated catalyst at 350° C. is 82.6%.

[0058] Example 2

[0059] The complete flaked spent SCR catalyst was placed in a 0.5 mol / L glycine solution with a pH of 1 at a mass-to-volume ratio of 1 g:20 mL and soaked at 70°C for 12 h. The catalyst was then removed and the leachate was retained. The catalyst was washed with deionized water and dried to obtain a regenerated catalyst.

[0060] In this embodiment, the Tl extraction rate is 90.19%, the V retention rate is 75.8%, and the activity recovery rate of the regenerated catalyst at 350° C. is 98.5%. In addition, in this embodiment, the Pb extraction rate is 74.6%, and the K extraction rate is 74.7%.

[0061] Example 3

[0062] The complete flaked spent SCR catalyst was placed in a 0.5 mol / L glycine solution with a pH of 1 at a mass-to-volume ratio of 1 g:20 mL and soaked at 90°C for 12 h. The catalyst was then removed and the leachate was retained. The catalyst was washed with deionized water and dried to obtain a regenerated catalyst.

[0063] In this embodiment, the Tl extraction rate is 91.74%, the V retention rate is 59.8%, and the activity recovery rate of the regenerated catalyst at 350° C. is 90.4%.

[0064] Example 4

[0065] The complete flaked spent SCR catalyst was placed in a 0.5 mol / L glycine solution with a pH of 2 at a mass-to-volume ratio of 1 g:20 mL and soaked at 70°C for 12 h. The catalyst was then removed and the leachate was retained. The catalyst was washed with deionized water and dried to obtain a regenerated catalyst.

[0066] In this embodiment, the Tl extraction rate was 66.2%, the V retention rate was 85.3%, and the activity recovery rate of the regenerated catalyst at 350° C. was 55.1%.

[0067] Example 5

[0068] The complete flaked spent SCR catalyst was placed in a 0.5 mol / L glycine solution with a pH of 1 at a mass-to-volume ratio of 1 g:20 mL and soaked at 70°C for 6 h. The catalyst was then removed and the leachate was retained. The catalyst was washed with deionized water and dried to obtain a regenerated catalyst.

[0069] In this embodiment, the Tl extraction rate is 75.4%, the V retention rate is 88.06%, and the activity recovery rate of the regenerated catalyst at 350° C. is 79.7%.

[0070] Example 6

[0071] The complete sheet-like spent SCR catalyst was placed in a 0.5 mol / L, pH=1 glycine solution at a mass volume ratio of 1 g:20 mL and soaked at 70°C for 8 h. The catalyst was then removed and the leachate was retained. The catalyst was washed with deionized water and dried to obtain a regenerated catalyst.

[0072] In this embodiment, the Tl extraction rate is 80.5%, the V retention rate is 77.65%, and the activity recovery rate of the regenerated catalyst at 350° C. is 90%.

[0073] Example 7

[0074] The complete flaky spent SCR catalyst was placed in a 0.5 mol / L, pH=1 glycine solution at a mass volume ratio of 1 g:20 mL and soaked at 70°C for 10 h. The catalyst was then removed and the leachate was retained. The catalyst was washed with deionized water and dried to obtain a regenerated catalyst.

[0075] In this embodiment, the Tl extraction rate is 83.6%, the V retention rate is 76.38%, and the activity recovery rate of the regenerated catalyst at 350° C. is 87%.

[0076] Example 8

[0077] The complete flaky spent SCR catalyst was placed in a 0.5 mol / L glycine solution with a pH of 1 at a mass-to-volume ratio of 1 g:20 mL and soaked at 70°C for 14 h. The catalyst was then removed and the leachate was retained. The catalyst was washed with deionized water and dried to obtain a regenerated catalyst.

[0078] In this embodiment, the Tl extraction rate is 91.21%, the V retention rate is 60.21%, and the activity recovery rate of the regenerated catalyst at 350° C. is 76.1%.

[0079] Comparative Example 1

[0080] The complete flaked spent SCR catalyst was placed in a sulfuric acid solution with a pH of 1 at a mass volume ratio of 1 g:20 mL and soaked at 70°C for 12 hours. The catalyst was then removed and the leachate was retained. The catalyst was washed with deionized water and dried to obtain a regenerated catalyst.

[0081] In this comparative example, the Tl extraction rate was 25.4%, the V retention rate was 78.9%, and the activity recovery rate of the regenerated catalyst at 350° C. was 52.7%.

[0082] Analysis example 2

[0083] Activity tests were conducted on 0.2 g of fresh V2O5-WO3 / TiO2 catalyst in the 40-60 mesh range, spent SCR catalyst, and regenerated catalyst (Example 2) in a fixed-bed quartz reactor. The reaction gas consisted of 500 ppm NO, 500 ppm NH3, 3% O2, and N2 as the balance gas; the total flow rate was 200 mL / min. -1 , the corresponding gas hourly space velocity (GHSV) is 60000 mL·g -1 ·h -1 ; Continuously monitor NO with flue gas analyzer x The test temperature range is from 200 to 450℃.

[0084] See also Figure 3 As shown, it can be seen that within the range of 200-450°C, the activity of the regenerated catalyst can be restored to the level of the fresh catalyst.

[0085] Note: When determining the activity recovery rate in other examples and comparative examples, the activity test process in this analysis example was used to perform NO x The conversion rate was detected, but the specific test temperature shall be subject to the description in each embodiment and comparative example.

[0086] Example 9

[0087] The leachate (from Example 2) was concentrated to a thallium concentration of 1800 mg / L, and then NaCl was added to the leachate to make the NaCl concentration 30 g / L. After aging at 30° C. for 4 h, the mixture was centrifuged and solid-liquid separated to obtain TlCl solid.

[0088] In this embodiment, the Tl precipitation rate is 54.7%.

[0089] Example 10

[0090] The leachate (from Example 2) was concentrated to a thallium concentration of 1800 mg / L, and then NaCl was added to the leachate to make the NaCl concentration 30 g / L. After aging at 30° C. for 8 h, the mixture was centrifuged and the solid-liquid separation was performed to obtain TlCl solid.

[0091] In this embodiment, the Tl precipitation rate is 70.8%.

[0092] Example 11

[0093] The leachate (from Example 2) was concentrated to a thallium concentration of 1800 mg / L, and then NaCl was added to the leachate to make the NaCl concentration 30 g / L. After aging at 30° C. for 12 h, the mixture was centrifuged and solid-liquid separated to obtain TlCl solid.

[0094] In this embodiment, the Tl precipitation rate is 70%.

[0095] Example 12

[0096] The leachate (from Example 2) was concentrated to a thallium concentration of 1800 mg / L, and then NaCl was added to the leachate to make the NaCl concentration 30 g / L. After aging at 5°C for 8 h, the mixture was centrifuged and solid-liquid separated to obtain TlCl solid.

[0097] In this embodiment, the T1 precipitation rate is 94.2%.

[0098] Example 13

[0099] The leachate (from Example 2) was concentrated to a thallium concentration of 1800 mg / L, and then NaCl was added to the leachate to make the NaCl concentration 30 g / L. After aging at 10° C. for 8 h, the mixture was centrifuged and solid-liquid separated to obtain TlCl solid.

[0100] In this embodiment, the T1 precipitation rate is 79.5%.

[0101] Example 14

[0102] The leachate (from Example 2) was concentrated to a thallium concentration of 1800 mg / L, and then NaCl was added to the leachate to make the NaCl concentration 30 g / L. After aging at 15° C. for 8 h, the mixture was centrifuged and solid-liquid separated to obtain TlCl solid.

[0103] In this embodiment, the T1 precipitation rate is 75.6%.

[0104] Example 15

[0105] The leachate (from Example 2) was concentrated to a thallium concentration of 1800 mg / L, and then NaCl was added to the leachate to make the NaCl concentration 30 g / L. After aging at 20°C for 8 h, the mixture was centrifuged and solid-liquid separated to obtain TlCl solid.

[0106] In this embodiment, the Tl precipitation rate is 70.7%.

[0107] Example 16

[0108] The leachate (from Example 2) was concentrated to a thallium concentration of 1800 mg / L, and then NaCl was added to the leachate to make the NaCl concentration 30 g / L. After aging at 25° C. for 8 h, the mixture was centrifuged and solid-liquid separated to obtain TlCl solid.

[0109] In this embodiment, the T1 precipitation rate is 72.1%.

[0110] Example 17

[0111] The leachate (from Example 2) was concentrated to a thallium concentration of 1800 mg / L, and then NaCl was added to the leachate to make the NaCl concentration 15 g / L. After aging at 5°C for 8 h, the mixture was centrifuged and solid-liquid separated to obtain TlCl solid.

[0112] In this embodiment, the T1 precipitation rate is 88.8%.

[0113] Example 18

[0114] The leachate (from Example 2) was concentrated to a thallium concentration of 1800 mg / L, and then NaCl was added to the leachate to make the NaCl concentration 25 g / L. After aging at 5°C for 8 h, the mixture was centrifuged and solid-liquid separated to obtain TlCl solid.

[0115] In this embodiment, the Tl precipitation rate is 93.5%.

[0116] Example 19

[0117] The leachate (from Example 2) was concentrated to a thallium concentration of 1800 mg / L, and then NaCl was added to the leachate to make the NaCl concentration 40 g / L. After aging at 5°C for 8 h, the mixture was centrifuged and solid-liquid separated to obtain TlCl solid.

[0118] In this example, the precipitation rate of Tl was 94.5%; see Figure 4 As shown in Figure 3, the recovery of Tl resources is achieved by precipitation of Tl with chloride salts.

[0119] The above technical solutions of the present invention are only preferred embodiments of the present invention and do not limit the patent scope of the present invention. All equivalent structural transformations made by using the contents of the present invention's description and drawings under the technical concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A method for in-situ regeneration of a Tl-poisoned SCR catalyst, characterized in that: include: The Tl-poisoned SCR catalyst is placed in a glycine solution, and thallium leaching solution and regenerated SCR catalyst are obtained after solid-liquid separation.

2. The method for in-situ regeneration of a Tl poisoned SCR catalyst according to claim 1, characterized in that: In the Tl-poisoned SCR catalyst, the mass proportion of the Tl element is 1-5%, and the mass proportion of the V element is 0.5-1%; in the Tl-poisoned SCR catalyst, the mass proportion of the Pb element is 0.005-0.02%, and the mass proportion of the K element is 0.1-0.2%.

3. The method for in-situ regeneration of a Tl poisoned SCR catalyst according to claim 1, wherein: The process of placing the Tl-poisoned SCR catalyst in a glycine solution includes: soaking the Tl-poisoned SCR catalyst in the glycine solution; the concentration of the glycine solution is 0.1-1 mol / L; the pH of the glycine solution is less than 2; the soaking is carried out at a temperature of 20-95°C; the soaking time is 5-15 hours; and the soaking is carried out under stirring conditions.

4. The method for in-situ regeneration of a T1-poisoned SCR catalyst according to claim 3, characterized in that: The concentration of the glycine solution is 0.3-0.7 mol / L; the pH of the glycine solution is 0.5-1.5; the soaking is performed at a temperature of 65-95° C.; and the soaking time is 8-13 hours.

5. The method for in-situ regeneration of a T1-poisoned SCR catalyst according to claim 4, characterized in that: The soaking is carried out at a temperature of 65-75° C. and for a duration of 11-13 hours.

6. The method for in-situ regeneration of a Tl-poisoned SCR catalyst according to any one of claims 1 to 5, characterized in that: The Tl poisoned SCR catalyst is placed in the glycine solution in the form of a sheet; the mass volume ratio of the Tl poisoned SCR catalyst to the glycine solution is 1g:10-50mL.

7. A method for recycling T1 resources, characterized in that: include: The thallium leachate is obtained by the in-situ regeneration method of the Tl-poisoned SCR catalyst according to any one of claims 1 to 6; then, the thallium leachate is subjected to thallium precipitation treatment, and a thallium-containing precipitate is obtained after solid-liquid separation.

8. The method for T1 resource recovery according to claim 7, wherein: The thallium precipitation treatment includes: adding chloride salt to the unconcentrated thallium leachate for aging; or adding chloride salt to the concentrated thallium leachate for aging.

9. The method for T1 resource recovery according to claim 8, wherein: The aging is carried out at a temperature of 2-8° C.; the concentration of the chloride salt in the thallium leaching solution is 10-50 g / L; and the aging time is 6-15 hours.

10. The method for recycling T1 resources according to any one of claims 7 to 9, characterized in that: The chloride salt includes one or more of KCl, NaCl, and MgCl2.

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