A method for in-situ regeneration of a Tl-poisoned SCR catalyst and recovery of Tl resources

Abstract

The application provides a method for in-situ regeneration of Tl-poisoned SCR catalyst and recovery of Tl resources, and belongs to the field of waste SCR catalyst recovery; the Tl-poisoned SCR catalyst is placed in a glycine solution, and after solid-liquid separation, a thallium leaching solution and a regenerated SCR catalyst are obtained; then, the thallium leaching solution is subjected to thallium precipitation treatment, and after solid-liquid separation, a thallium-containing precipitate is obtained. The application utilizes the specific coordination of glycine and Tl to selectively extract Tl from the catalyst, restores the activity of the SCR catalyst, recovers the extracted Tl, realizes the resource utilization of waste, and reduces the environmental risk.

Description

Technical Field

[0001] This invention relates to the field of spent SCR catalyst recycling, and in particular to a method for in-situ regeneration of Tl poisoned SCR catalyst and recovery of Tl resources. Background Technology

[0002] Selective catalytic reduction (SCR) denitrification is currently the most mature and reliable method for NO removal. x Control Technology. Commercial V₂O₅-WO₃ / TiO₂ catalysts have been widely used in industries such as thermal power, coking, cement, glass, and steel. The lifespan 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 (US$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 treat these spent catalysts and reuse them as resources.

[0003] Chemical poisoning has long been considered a key factor leading to the deactivation of V₂O₅-WO₃ / TiO₂ catalysts. Various harmful elements present in industrial raw materials and fuels enter flue gas under high-temperature conditions in the form of oxides, chlorides, and sulfates, causing poisoning of V₂O₅-WO₃ / TiO₂ catalysts. 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, causing severe catalyst deactivation. Furthermore, Tl is one of the most biotoxic heavy metals, exceeding the toxicity of Pb, Hg, Cd, Cu, or Zn to humans. However, research on the regeneration of Tl-poisoned catalysts remains limited. Traditional acid and alkali leaching regeneration methods suffer from significant vanadium loss, low activity recovery, high cost, and difficulty in industrialization. Therefore, the regeneration of Tl-poisoned catalysts remains a challenging task, requiring the development of a regenerator with a specific affinity for Tl.

[0004] Therefore, it is necessary to provide a method for in-situ regeneration of Tl-poisoned SCR catalysts and recovery of Tl resources, so as to solve or at least alleviate the technical problem of how to effectively restore the activity of SCR catalysts and efficiently extract Tl. Summary of the Invention

[0005] The main objective of this invention is to provide a method for in-situ regeneration of Tl-poisoned SCR catalysts and recovery of Tl resources, aiming to solve the aforementioned technical problems of how to effectively restore the activity of SCR catalysts and efficiently extract Tl.

[0006] To achieve the above objectives, 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 percentage of Tl is 1-5%, and the mass percentage of V is 0.5-1%; in the Tl-poisoned SCR catalyst, the mass percentage of Pb is 0.005-0.02%, and the mass percentage of K is 0.1-0.2%.

[0008] Further, the process of placing the Tl-poisoned SCR catalyst in a glycine solution includes: immersing 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 immersion is carried out at a temperature of 20-95°C; the immersion time is 5-15 h; and the immersion is carried out under stirring conditions.

[0009] Further, 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 carried out at a temperature of 65-95℃; and the soaking time is 8-13 hours.

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

[0011] Furthermore, the Tl-poisoned SCR catalyst is placed in the glycine solution in a sheet-like form; the mass-to-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 Tl resource recovery, comprising: obtaining the thallium leachate by in-situ regeneration of the Tl-poisoned SCR catalyst as described above; and then subjecting the thallium leachate to thallium precipitation treatment, and obtaining 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 leachate is 10-50 g / L; and the aging time is 6-15 h.

[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 the problems of non-selective separation of poisoned metals, significant loss of active components, and high secondary molding costs in powder regeneration, this invention provides a method for in-situ regeneration of Tl-poisoned SCR catalysts and recovery of Tl resources. This invention utilizes coordination regulation, specifically coordinating glycine with Tl, to selectively separate the poisoned element from the deactivated spent SCR catalyst, while the active component V is well retained in the catalyst. The activity of the regenerated SCR catalyst can reach the level of fresh catalyst, and Tl resources are recovered through chloride precipitation. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0019] Figure 1 In Example 1 of this invention, the glycine solution (corresponding to glycine in the figure) and the leachate (corresponding to glycine-Tl in the figure) are analyzed. + The infrared spectrum of )

[0020] Figure 2 In Example 1 of this invention, the glycine solution (corresponding to glycine in the figure) and the leachate (corresponding to glycine-Tl in the figure) are analyzed. + Raman spectra of )

[0021] Figure 3 In Example 2 of this invention, the NO content of the fresh V2O5-WO3 / TiO2 catalyst (corresponding to fresh in the figure), the spent SCR catalyst (corresponding to poisoned in the figure), and the regenerated catalyst (corresponding to regenerated in the figure) was analyzed. x Conversion rate; the activity of the regenerated catalyst is similar to that of the fresh catalyst.

[0022] Figure 4 The XRD pattern of the precipitated sample in Embodiment 19 of the present invention shows that the recovery of Tl resources was achieved.

[0023] The realization of the objective, functional characteristics and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0024] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] Furthermore, the technical solutions of the various embodiments of the present invention can be combined with each other, but only if they are based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0026] When numerical ranges are given in the embodiments, it should be understood that, unless otherwise stated in the present invention, both endpoints of each numerical range and any value between the two endpoints may be selected. Unless otherwise defined, all technical and scientific terms used in this invention, as well as the prior art known to those skilled in the art and the description of this invention, may be implemented using any prior art methods, devices, and materials similar to or equivalent to those described, used, or made of materials in the embodiments of this invention.

[0027] In the embodiments, comparative examples, and analytical examples of this invention, the spent SCR catalyst was a Tl-poisoned V₂O₅-WO₃ / TiO₂ catalyst, where Tl in the spent SCR catalyst (Tl-poisoned SCR catalyst) refers to monovalent thallium; the dimensions of the intact sheet-like spent SCR catalyst were 2 cm x 1 cm; soaking was carried out under stirring conditions at a stirring speed of 600 rpm; drying was performed at 60°C for 12 hours; aging was understood as standing. In Examples 1-8 of this invention, sulfuric acid solution was used to adjust the pH.

[0028] In this 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 = NOregenerated of the catalyst x Conversion rate / NO of fresh catalyst x Conversion rate (under the same conditions).

[0029] The present invention provides a method for in-situ regeneration of 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.

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

[0031] In this 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 industries such as thermal power, steel, coking, cement, glass, and ceramics.

[0032] In this invention, the process of placing the Tl-poisoned SCR catalyst in a glycine solution includes: immersing the Tl-poisoned SCR catalyst in the glycine solution; the immersion can be carried out under stirring conditions.

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

[0034] In this 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 this invention, the Tl-poisoned SCR catalyst is placed in the glycine solution in sheet form; the sheet-like Tl-poisoned SCR catalyst has a size of 2cm x 1cm. Specifically, the spent SCR catalyst (Tl-poisoned SCR catalyst) is cut into complete sheets and then immersed in the glycine solution.

[0036] In this invention, the mass-to-volume ratio of the Tl-poisoned SCR catalyst to the glycine solution can be 1g:10-50mL, or more specifically 1g:10-30mL.

[0037] The present invention also provides a method for recovering Tl resources, comprising: obtaining the thallium leachate by in-situ regeneration of the Tl-poisoned SCR catalyst as described above; then, subjecting the thallium leachate to 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; the thallium concentration in the concentrated thallium leachate 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 adding chloride salt to the unconcentrated thallium leachate for aging, the thallium concentration in the unconcentrated thallium leachate may also be controlled to the above-mentioned concentrated thallium concentration.

[0039] Aging by adding chloride salt to the unconcentrated thallium leachate is as follows: directly adding chloride salt to the thallium leachate for aging; aging by adding chloride salt to the concentrated thallium leachate is as follows: concentrating the thallium leachate and then adding chloride salt to the thallium leachate for aging.

[0040] In this 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 10-50 g / L, more preferably 15-40 g / L, 25-40 g / L, or 25-30 g / L; the aging time is 6-15 h, more preferably 7-13 h, 8-12 h, or 7-9 h.

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

[0042] In this invention, the -COOH group of glycine has a specific coordination effect with Tl, and H + The introduction of [a specific ingredient] can enhance this coordination effect. This invention avoids the simultaneous extraction of poisoned metals and active ingredient V, enabling selective separation of poisoned metals and effective restoration of catalyst activity. Specifically, this invention addresses the problems of non-selective separation of poisoned metals, significant loss of active ingredients, and high secondary molding costs in powder regeneration of current regeneration technologies. It provides a method for in-situ regeneration of Tl-poisoned SCR catalysts and recovery of Tl resources. This invention involves immersing intact, sheet-like waste SCR catalyst in a glycine solution for a period of time. Through the specific coordination between glycine and Tl, Tl is extracted from the catalyst, simultaneously achieving catalyst regeneration. Then, TlCl is recovered from the leachate using a chloride precipitation method.

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

[0044] Analysis example 1

[0045] I. Comparison of Regenerants:

[0046] Waste SCR catalyst was placed in the test solution in powder form at a mass-to-volume ratio of 1g:5mL and soaked at 25℃ for 12h. After solid-liquid separation, leachate and leachate residue were obtained.

[0047] In the spent SCR catalyst of this analytical example, the mass percentage of Tl was 2.73%, V was 0.84%, Pb was 0.01%, and K was 0.14%. Subsequent examples, comparative examples, and analytical examples all used the same batch of spent SCR catalyst as this analytical example, and the results were analyzed according to the elemental contents described in this analytical example.

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

[0049] In this analytical 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 analytical example, when using a 0.5 mol / L acetic acid solution, the extraction rate of Tl was 18.73%, and the retention rate of V was 99.5%.

[0051] In this analytical 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] II. 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 and COO respectively - Symmetrical stretching, NH3 symmetrical stretching and COO - Asymmetric stretching. The slight redshift of the COO- characteristic peak indicates Tl. + It 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 these locations belong to COO. - Asymmetric stretching, C=O vibration, CH2 bending, COO- Symmetrical stretching, CH2 rocking and NH3 + The oscillation is evident in the shift of the C=O vibrational peak, indicating that Tl+ preferentially coordinates at the C=O site of the carboxyl group.

[0055] Example 1

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

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

[0058] Example 2

[0059] At a mass-to-volume ratio of 1g:20mL, the intact sheet-like spent SCR catalyst was placed in a 0.5mol / L glycine solution with pH=1 and soaked at 70℃ for 12h. Then, the catalyst was removed, and the leachate was retained. The catalyst was washed with deionized water and dried to obtain the regenerated catalyst.

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

[0061] Example 3

[0062] At a mass-to-volume ratio of 1g:20mL, the intact sheet-like spent SCR catalyst was placed in a 0.5mol / L glycine solution with pH=1 and soaked at 90℃ for 12h. Then, the catalyst was removed, and the leachate was retained. The catalyst was washed with deionized water and dried to obtain the regenerated catalyst.

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

[0064] Example 4

[0065] At a mass-to-volume ratio of 1g:20mL, the intact sheet-like spent SCR catalyst was placed in a 0.5mol / L glycine solution with pH=2 and soaked at 70℃ for 12h. Then, the catalyst was removed, and the leachate was retained. The catalyst was washed with deionized water and dried to obtain the 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] At a mass-to-volume ratio of 1g:20mL, the intact sheet-like spent SCR catalyst was placed in a 0.5mol / L glycine solution with pH=1 and soaked at 70℃ for 6h. Then, the catalyst was removed, and the leachate was retained. The catalyst was washed with deionized water and dried to obtain the regenerated catalyst.

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

[0070] Example 6

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

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

[0073] Example 7

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

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

[0076] Example 8

[0077] At a mass-to-volume ratio of 1g:20mL, the intact sheet-like spent SCR catalyst was placed in a 0.5mol / L glycine solution with pH=1 and soaked at 70℃ for 14h. Then, the catalyst was removed, and the leachate was retained. The catalyst was washed with deionized water and dried to obtain the regenerated catalyst.

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

[0079] Comparative Example 1

[0080] At a mass-to-volume ratio of 1g:20mL, the intact sheet-like spent SCR catalyst was placed in a sulfuric acid solution with pH=1 and soaked at 70℃ for 12h. Then, the catalyst was removed, and the leachate was retained. The catalyst was washed with deionized water and dried to obtain the 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℃ was 52.7%.

[0082] Analysis example 2

[0083] 0.2 g of fresh V₂O₅-WO₃ / TiO₂ catalyst, spent SCR catalyst, and regenerated catalyst (Example 2) in the 40-60 mesh range were used for an activity test in a fixed-bed quartz reactor. The reaction gases were 500 ppm NO, 500 ppm NH₃, 3% O₂, and N₂ as the equilibrium gases; the total flow rate was 200 mL / min. -1 The corresponding gas hourly space velocity (GHSV) is 60,000 mL·g -1 ·h -1 Continuous monitoring of NO using a flue gas analyzer x The concentration was measured at a temperature range of 200 to 450°C.

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

[0085] Note: Other examples and comparative examples used the activity test procedure described in this analytical example to determine the NO recovery rate. x Conversion rate was measured, but the specific test temperature was as described in each example and comparative example.

[0086] Example 9

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

[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. Then, NaCl was added to the leachate to make the NaCl concentration 30 g / L. After aging at 30°C for 8 hours, the mixture was centrifuged and the solid and liquid were separated to obtain solid TlCl.

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

[0092] Example 11

[0093] The leachate (from Example 2) was concentrated to a thallium concentration of 1800 mg / L. 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 the solid and liquid were separated to obtain solid TlCl.

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

[0095] Example 12

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

[0097] In this embodiment, the precipitation rate of Tl was 94.2%.

[0098] Example 13

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

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

[0101] Example 14

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

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

[0104] Example 15

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

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

[0107] Example 16

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

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

[0110] Example 17

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

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

[0113] Example 18

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

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

[0116] Example 19

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

[0118] In this embodiment, the precipitation rate of Tl was 94.5%; see [link to example]. Figure 4 As shown, Tl was recovered by precipitating it with chloride salts.

[0119] The above technical solutions of the present invention are merely preferred embodiments of the present invention and do not limit the patent scope of the present invention. All equivalent structural transformations made under the technical concept of the present invention using the contents of the present invention specification and drawings, or direct / indirect applications 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 was placed in a glycine solution, and after solid-liquid separation, thallium leachate and regenerated SCR catalyst were obtained.

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

3. The method for in-situ regeneration of Tl-poisoned SCR catalyst according to claim 1, characterized in that, The process of placing the Tl-poisoned SCR catalyst in a glycine solution includes: immersing 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 immersion is carried out at a temperature of 20-95°C; the immersion time is 5-15 h; and the immersion is carried out under stirring conditions.

4. The method for in-situ regeneration of Tl-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 carried out at a temperature of 65-95℃; and the soaking time is 8-13 h.

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

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

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