Method for extracting and recovering copper and zinc from copper-based waste catalyst

Abstract

The invention belongs to the technical field of hydrometallurgy, and particularly relates to a method for extracting and recovering copper and zinc from a copper-based waste catalyst, which comprises the following steps: 1) leaching: carrying out in-situ leaching on the copper-based waste catalyst by using acid to obtain a leachate; 2) extracting copper: extracting the leachate by using Mextra984H, and adjusting the balance pH to 2-2.5 during extraction to obtain an extraction phase I and a raffinate phase I; 3) reverse extraction and enrichment of copper: performing reverse extraction on the extraction phase I to obtain a copper sulfate solution, and performing electrodeposition on the copper sulfate solution to obtain cathode copper; 4) extracting zinc: extracting the raffinate phase I by using Cyanex 301 to obtain an extraction phase II and a raffinate phase II; and (5) zinc is enriched through reverse extraction, specifically, the extraction phase II is subjected to reverse extraction through a hydrochloric acid solution, and a zinc chloride solution is obtained through enrichment. According to the method, step-by-step recovery of valuable metal copper and zinc in the copper-based waste catalyst is achieved, the alkali consumption is effectively reduced, the energy consumption is reduced, the process is simple, and the applicability is good.

Description

Technical Field

[0001] The invention belongs to the technical field of hydrometallurgy, and in particular relates to a method for extracting and recovering copper and zinc from copper-based waste catalysts. Background Art

[0002] Waste copper-based catalysts primarily refer to catalysts used in the fertilizer and ammonia synthesis industry for low-carbon transformation, methanol synthesis, and alcohol synthesis. These catalysts are characterized by high usage, short lifespans, and a high concentration of major components. If left unused, they not only cause environmental pollution but also waste resources. Methods for recovering spent catalysts generally include dry, wet, combined dry and wet, and non-separation methods. Currently, chlorination volatilization or smelting separation methods are commonly used abroad to recover copper and zinc. These drawbacks include complex processes, high costs, and environmental pollution. Domestically, the acid dissolution method is commonly used. This involves treating spent catalysts with sulfuric or hydrochloric acid solutions, converting the copper and zinc elements into ions in solution. Zinc or iron powder is then added to the solution to convert the copper. However, this method also has limitations. The copper-zinc compounds it produces are of lower quality and grade. Impurities such as iron and aluminum are also introduced into the solution, resulting in a lengthy and difficult-to-control process. The recovered product contains a high concentration of impurities, making purification and removal difficult. In addition, there are also studies on the use of dilute nitric acid solution to dissolve waste catalysts, such as "Recovery of Waste Methanol Catalyst" (Li Guanglin, [J] Shandong Chemical Industry, 2004-06-30), which discloses that copper, zinc and their oxides in the waste methanol catalyst are dissolved into a nitrate mixture, and the aluminum oxide suspension that is difficult to dissolve in acid is filtered out to achieve aluminum removal; alkali is added to the liquid after aluminum removal to remove Fe 3+ The solution pH is controlled at approximately 4.1, producing an Fe(OH)3 precipitate. The Fe(OH)3 precipitate is then filtered out to yield a highly concentrated and pure copper nitrate and zinc nitrate mixture, which serves as the raw material for preparing a new methanol catalyst. However, in the above method, the solution after aluminum removal is strongly acidic. Therefore, if the solution pH is required to be approximately 4.1 during iron removal, high alkali consumption is required. Furthermore, the spent methanol catalyst requires calcination and acid leaching, which is energy-intensive. Alternatively, ammonia leaching, oxidative sulfur removal, ammonia evaporation, and heating and hydrolysis are used to produce basic copper carbonate and basic zinc carbonate precipitates. These precipitates then require nitric acid dissolution to convert them into copper nitrate and zinc nitrate, which serve as the raw materials for the new methanol catalyst. This recovery process is lengthy and requires intermediate heating and ammonia evaporation, making it environmentally unfriendly. Furthermore, the copper-zinc compounds produced by this method are of low quality. Therefore, it is necessary to develop a new process for recycling spent copper-based catalysts to reduce alkali consumption and energy consumption. Summary of the Invention

[0003] The present invention aims to provide a method for extracting and recovering copper and zinc from copper-based waste catalysts, so as to solve the problems of large alkali consumption and high energy consumption in the existing acid leaching method for recovering copper-based waste catalysts.

[0004] In order to achieve the above object, the present invention provides a method for extracting and recovering copper and zinc from copper-based waste catalysts, comprising the following steps:

[0005] S1. Leaching: In-situ leaching of the copper-based spent catalyst using acid to obtain a leachate containing copper, zinc, and aluminum;

[0006] S2. Copper extraction: extracting the leachate obtained in step S1 using Mextral 984H, and adjusting the equilibrium pH during extraction to 2-2.5 to obtain an extract phase I and a raffinate phase I;

[0007] S3, stripping and enriching copper: using a copper-containing sulfuric acid solution to strip the extraction phase I to obtain a copper sulfate solution, and then electrowinning the copper sulfate solution to obtain cathode copper;

[0008] S4, zinc extraction: extracting the raffinate phase I obtained in step S2 using Cyanex 301 to obtain an extract phase II and a raffinate phase II;

[0009] S5. Back-extraction and zinc enrichment: Use hydrochloric acid solution to back-extract the extraction phase II to obtain zinc chloride solution through enrichment.

[0010] The working principle and beneficial effects of this solution are as follows: It uses a two-step extraction process to recover copper and zinc from copper-based spent catalysts in separate steps. After copper extraction, the acidity of the raffinate phase I is high, eliminating the need to add alkali to adjust the pH of the raffinate phase I, allowing direct zinc extraction. This effectively reduces alkali consumption. Furthermore, the copper-based spent catalyst can be processed directly in situ without pretreatment such as pulverization, effectively reducing energy consumption. Furthermore, this solution achieves copper recovery rates exceeding 99.9% and zinc recovery rates reaching 99.5%, yielding copper plates and high-purity zinc chloride products.

[0011] The selection of extractants and the optimization of the extraction process are one of the difficulties of this solution. The inventors have tried to use CLX50, P272, TBP, P204, P507, V10, 336At, and Cyanex 301 for zinc extraction. The results showed that: the pH value of CLX50 extraction was high, and the organic phase was turbid and difficult to separate when the equilibrium pH was adjusted with alkali, resulting in a low extraction rate; the three phosphorus extractants P272, P204, and P507 had a low separation coefficient between zinc and aluminum when extracting zinc, and the equilibrium pH value of zinc and aluminum was 2-3. Using this type of extractant to separate zinc and aluminum required more stages, and the process was more complicated; when using V10 for extraction, zinc and aluminum would co-extract and the equilibrium pH value would be above 6. A large amount of alkali needed to be added during the extraction process to achieve zinc extraction, and the organic phase was difficult to separate after the pH was increased; emulsification and a large amount of flocculants would appear during 336At extraction, making phase separation difficult, resulting in large losses of extractant and high costs; only Cyanex When 301 is extracted, not only does it not require the addition of alkali, it can also well separate zinc and aluminum, with a high zinc extraction rate and good purity.

[0012] In summary, this solution selects a suitable extractant to achieve the step-by-step recovery of valuable metals (copper and zinc) from copper-based waste catalysts, producing corresponding copper and zinc products, respectively, which is conducive to resource recovery. The copper-based waste catalysts in this solution do not need to undergo pretreatment such as crushing and can be directly subjected to in-situ acid leaching, effectively reducing energy consumption. Furthermore, in terms of process selection, the raffinate after copper recovery is directly extracted using the extractant without the need for alkali adjustment, effectively reducing alkali consumption. Finally, this solution has a simple process and uses conventional extraction equipment, which is low-cost and easy to operate. It is suitable for use in various factories and can also be applied to the recovery of various copper-based waste catalysts and other CuO / ZnO / Al2O3-based non-methanol catalysts, with good applicability.

[0013] Optionally, in step S1, the acid is one or more of sulfuric acid, hydrochloric acid and nitric acid.

[0014] Optionally, in step S1, the concentration of the acid is 20 to 100 g / L, the liquid-solid ratio of the leaching is 15 to 50:1, and the leaching time is 0.5 to 4 hours.

[0015] Optionally, in step S2, the volume concentration of Mextral 984H is 10-30%, the extraction method is countercurrent extraction, the number of extraction stages is 2-4, the extraction phase ratio of each stage is 2-2.5:1, and the extraction time of each stage is 3-10 minutes.

[0016] During the extraction process, the concentration of the extractant, the duration of the extraction, and the number of extraction stages all affect the extraction effect and reagent consumption to a certain extent. This solution can extract as much copper as possible from the leachate, minimizing the amount of copper introduced into the subsequent zinc extraction process, thereby ensuring the purity of the zinc chloride product.

[0017] Optionally, in step S2, phase separation is performed after extraction to obtain an extraction phase I and a raffinate phase I, and the phase separation time is 5 to 10 minutes.

[0018] Optionally, in step S3, the stripping method is countercurrent stripping, the number of stripping stages is 2 to 4, the stripping ratio of each stage is 1 to 5:1, and the stripping time of each stage is 3 to 8 minutes.

[0019] Optionally, in step S4, the volume concentration of Cyanex 301 is 5-30%, the extraction method is countercurrent extraction, the number of extraction stages is 2-4, the extraction phase ratio of each stage is 1:1-2.5, and the extraction time of each stage is 3-5 minutes.

[0020] Optionally, in step S5, the stripping phase ratio is 1 to 3:1.

[0021] Optionally, in step S5, the concentration of the hydrochloric acid solution is 3-6 mol / L.

[0022] Optionally, the raffinate phase II in step S4 is used as one of the sources of acid in step S1.

[0023] The raffinate phase II is returned to the leaching step for recycling, which reduces acid consumption and thus reduces recovery costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 Schematic diagram of a process flow of a method for extracting and recovering copper and zinc from a copper-based waste catalyst according to an embodiment of the present invention; DETAILED DESCRIPTION

[0025] The following describes the embodiments of the present invention through specific examples. Those skilled in the art will readily understand the other advantages and benefits of the present invention from the disclosure herein. The present invention may also be implemented or applied through various other specific embodiments, and the details in this specification may be modified or altered based on different viewpoints and applications without departing from the spirit of the present invention.

[0026] The present invention provides a method for extracting and recovering copper and zinc from a copper-based waste catalyst, comprising the following steps:

[0027] S1. Leaching: The copper-based spent catalyst is subjected to in-situ acid leaching to obtain a leachate containing copper, zinc, and aluminum. The acid is one or more of sulfuric acid, hydrochloric acid, and nitric acid, with an acid concentration of 20-100 g / L, a liquid-to-solid ratio of 15-50:1, a leaching time of 0.5-4 hours, and a leaching temperature of 30°C.

[0028] S2. Copper Extraction: The leachate obtained in step S1 is extracted using Mextral 984H, and the equilibrium pH during extraction is adjusted to 2-2.5. After extraction, phase separation is performed to obtain an extract phase I and a raffinate phase I. The phase separation time is 5-10 minutes. The volume concentration of Mextral 984H is 10-30%, the extraction method is countercurrent extraction, the number of extraction stages is 2-4, the extraction phase ratio of each stage is 2-2.5:1, and the extraction time of each stage is 3-10 minutes.

[0029] S3. Stripping and enriching copper: The extraction phase I is stripped with a copper-containing sulfuric acid solution to obtain a copper sulfate solution, and the copper sulfate solution is subjected to electrolysis to obtain cathode copper. The stripping method is countercurrent stripping, the number of stripping stages is 2 to 4, the stripping ratio of each stripping stage is 1 to 5:1, and the stripping time of each stripping stage is 3 to 8 minutes; the copper-containing sulfuric acid solution contains 35 to 38 g / L Cu and 175 to 185 g / L H2SO4.

[0030] S4, Zinc Extraction: Extraction of Raffinate Phase I obtained in Step S2 is performed using Cyanex 301. After extraction, phase separation is performed to obtain Extract Phase II and Raffinate Phase II. The volume concentration of Cyanex 301 is 5-30%, and the extraction method is countercurrent extraction. The number of extraction stages is 2-4, with a phase ratio of 1:1-2.5 for each stage, and an extraction time of 3-5 minutes for each stage. Raffinate Phase II in this step can be recycled to the leaching step (Step S1), thereby reducing the amount of acid used.

[0031] S5. Stripping and enriching zinc: Stripping the extraction phase II with a hydrochloric acid solution to obtain a zinc chloride solution after enrichment. The concentration of the hydrochloric acid solution is 3 to 6 mol / L, and the stripping phase ratio is 1 to 3:1.

[0032] The following specific examples are given to illustrate the present invention in detail. It should also be understood that the following examples are only used to specifically illustrate the present invention and cannot be understood as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the above content of the present invention all fall within the scope of protection of the present invention. The specific process parameters and the like in the following examples are only examples within a suitable range, that is, those skilled in the art can make a selection within a suitable range based on the description herein, and are not limited to the specific numerical values exemplified below.

[0033] Example 1

[0034] This embodiment provides a method for extracting and recovering copper and zinc from copper-based waste catalysts. The process flow of the method is basically as follows: Figure 1 As shown, the method includes the following steps:

[0035] S1. Leaching: In situ leaching of the copper-based spent catalyst was performed using a 50 g / L sulfuric acid solution (water as the solvent). The composition of the copper-based spent catalyst was as follows: 45.5% Cu, 5.5% Zn, and 4.86% Al. The leaching process was performed at a liquid-to-solid ratio of 25:1, a leaching time of 2 hours, and a temperature of 30°C. After leaching, a leachate was obtained by filtration. The leachate contained 17.07 g / L Cu, 2.03 g / L Zn, and 0.62 g / L Al, with a pH of 1.527.

[0036] S2. Copper Extraction: The leachate obtained in step S1 was extracted using Mextral 984H (kerosene solvent) at a volume concentration of 25%. The extraction process was a two-stage countercurrent extraction process with an extraction phase ratio (O / A) of 2.5:1 for each stage. The extraction duration for each stage was 3 minutes, and the equilibrium pH during extraction was adjusted to 2-2.5. After the extraction, the phases were separated for 5 minutes to obtain an extract phase I (Mextral 984H-loaded organic phase) and a raffinate phase I. The raffinate phase I contained 2.4 ppm of copper, and the copper recovery rate was greater than 99.9%.

[0037] S3. Stripping and enriching copper: copper-containing sulfuric acid solution is used as stripping solution to strip the extraction phase I. The stripping solution is prepared from copper sulfate, sulfuric acid and water. The stripping solution contains 35g / L Cu and 180g / L H2SO4. The stripping process is two-stage countercurrent stripping. The stripping ratio (O / A) of each stage of stripping is 1.5:1. The stripping time of each stage of stripping is 3min. After the stripping is completed, copper sulfate solution is obtained, and cathode copper is obtained by electrowinning the copper sulfate solution.

[0038] S4. Zinc extraction: The raffinate phase I is extracted using Cyanex 301 (kerosene as the solvent) at a volume concentration of 10%. The pH of the raffinate phase I does not need to be adjusted before extraction. The extraction process is a two-stage countercurrent extraction. The extraction phase ratio (O / A) of each stage is 1:1, and the extraction time of each stage is 3 minutes. After the extraction, the phases are separated to obtain an extraction phase II (Cyanex 301-loaded organic phase) and a raffinate phase II. The raffinate phase II contains 0.28 ppm zinc. The raffinate phase II is returned to step S1 for leaching.

[0039] S5. Stripping and enriching zinc: The extraction phase II was stripped using a 3 mol / L hydrochloric acid solution (solvent: water) with a stripping phase ratio (O / A) of 1:1. After seven cycles of stripping and enrichment, a zinc chloride solution with a zinc concentration of 13.88 g / L was obtained, wherein the impurity aluminum content was 2.1 ppm, and the zinc recovery rate was greater than 99.5%.

[0040] Thus, in this embodiment, the extraction rate of copper is 99.98%, the extraction rate of zinc is 99.98%, and the extraction rate of aluminum is 0.15%.

[0041] Example 2

[0042] This embodiment provides a method for extracting and recovering copper and zinc from copper-based waste catalysts. The process flow of the method is basically as follows: Figure 1 As shown, the method includes the following steps:

[0043] S1. Leaching: In situ leaching of the copper-based spent catalyst was performed using a 55 g / L sulfuric acid solution (water as the solvent). The composition of the copper-based spent catalyst was as follows: 55.61% Cu, 7.52% Zn, and 3.62% Al. The leaching process was performed at a liquid-to-solid ratio of 25:1, a leaching time of 1.5 hours, and a temperature of 30°C. After leaching, a leachate was obtained by filtration. The leachate contained 20.98 g / L Cu, 1.97 g / L Zn, and 0.54 g / L Al, with a pH of 1.417.

[0044] S2. Copper Extraction: The leachate obtained in step S1 was extracted using Mextral 984H (kerosene solvent) at a volume concentration of 25%. The extraction process was a three-stage countercurrent extraction process with an extraction phase ratio (O / A) of 2.5:1 for each stage. The extraction duration for each stage was 5 minutes, and the equilibrium pH during extraction was adjusted to 2-2.5. After the extraction, the phases were separated for 10 minutes to obtain an extract phase I (Mextral 984H-loaded organic phase) and a raffinate phase I. The raffinate phase I contained 2 ppm of copper, and the copper recovery rate was greater than 99.9%.

[0045] S3. Stripping and enriching copper: copper-containing sulfuric acid solution is used as stripping liquid to strip the extraction phase I. The stripping liquid is prepared from copper sulfate, sulfuric acid and water. The stripping liquid contains 35g / L Cu and 180g / L H2SO4. The stripping process is two-stage countercurrent stripping. The stripping ratio (O / A) of each stage of stripping is 1.4:1. The stripping time of each stage of stripping is 8 minutes. After the stripping is completed, copper sulfate solution is obtained, and cathode copper is obtained by electrowinning the copper sulfate solution.

[0046] S4. Zinc extraction: The raffinate phase I is extracted using Cyanex 301 (kerosene as the solvent) having a volume concentration of 20%. The pH of the raffinate phase I does not need to be adjusted before extraction. The extraction process is a two-stage countercurrent extraction. The extraction phase ratio (O / A) of each stage is 1:2.5, and the extraction time of each stage is 3 minutes. After the extraction, the phases are separated to obtain an extraction phase II (Cyanex 301-loaded organic phase) and a raffinate phase II. The raffinate phase II contains 1.45 ppm zinc. The raffinate phase II is returned to step S1 for leaching.

[0047] S5. Stripping and enriching zinc: The extraction phase II was stripped using a 3 mol / L hydrochloric acid solution (solvent: water) with a stripping phase ratio (O / A) of 5:3. After four cycles of stripping and enrichment, a zinc chloride solution with a zinc concentration of 32.01 g / L was obtained, wherein the impurity aluminum content was 5.61 ppm, and the zinc recovery rate was greater than 99.9%.

[0048] Thus, in this embodiment, the extraction rate of copper is 99.99%, the extraction rate of zinc is 99.92%, and the extraction rate of aluminum is 0.17%.

[0049] Example 3

[0050] This embodiment provides a method for extracting and recovering copper and zinc from copper-based waste catalysts. The process flow of the method is basically as follows: Figure 1 As shown, the method includes the following steps:

[0051] S1. Leaching: In situ leaching of the copper-based spent catalyst was performed using a 20 g / L sulfuric acid solution (water as the solvent). The composition of the copper-based spent catalyst was as follows: 55.61% Cu, 7.52% Zn, and 3.62% Al. The leaching process was performed at a liquid-to-solid ratio of 15:1, a leaching time of 2 hours, and a temperature of 30°C. After leaching, a leachate was obtained by filtration. The leachate contained 9.80 g / L Cu, 0.93 g / L Zn, and 0.17 g / L Al, with a pH of 2.484.

[0052] S2. Copper Extraction: The leachate obtained in step S1 was extracted using Mextral 984H (kerosene solvent) at a volume concentration of 25%. The extraction process was a two-stage countercurrent extraction process with an extraction phase ratio (O / A) of 2.5:1 for each stage. The extraction duration for each stage was 5 minutes, and the equilibrium pH during extraction was adjusted to 2-2.5. After the extraction, the phases were separated for 5 minutes to obtain an extract phase I (Mextral 984H-loaded organic phase) and a raffinate phase I. The raffinate phase I contained 3.5 ppm of copper, and the copper recovery rate was greater than 99.9%.

[0053] S3. Stripping and enriching copper: copper-containing sulfuric acid solution is used as stripping liquid to strip the extraction phase I. The stripping liquid is prepared from copper sulfate, sulfuric acid and water. The stripping liquid contains 35g / L Cu and 180g / L H2SO4. The stripping process is one-stage countercurrent stripping. The stripping ratio (O / A) of each stage of stripping is 2:1. The stripping time of each stage of stripping is 3min. After the stripping is completed, copper sulfate solution is obtained, and cathode copper is obtained by electrowinning the copper sulfate solution.

[0054] S4. Zinc extraction: The raffinate phase I is extracted using Cyanex 301 (kerosene as the solvent) having a volume concentration of 20%. The pH of the raffinate phase I does not need to be adjusted before extraction. The extraction process is a two-stage countercurrent extraction. The extraction phase ratio (O / A) of each stage is 1:2, and the extraction time of each stage is 3 minutes. After the extraction, the phases are separated to obtain an extraction phase II (Cyanex 301-loaded organic phase) and a raffinate phase II. The raffinate phase II contains 0.20 ppm zinc. The raffinate phase II is returned to step S1 for leaching.

[0055] S5. Stripping and enriching zinc: The extraction phase II was stripped using a 3 mol / L hydrochloric acid solution (solvent: water) with a stripping phase ratio (O / A) of 5:3. After four cycles of stripping and enrichment, a zinc chloride solution with a zinc concentration of 26.04 g / L was obtained, wherein the impurity aluminum content was 6.2 ppm, and the zinc recovery rate was greater than 99.9%.

[0056] Thus, in this embodiment, the extraction rate of copper is 99.96%, the extraction rate of zinc is 99.98%, and the extraction rate of aluminum is 0.758%.

[0057] Comparative Example 1

[0058] This comparative example differs from Example 1 only in the extraction solvent selected in step S4: 10% by volume of CLX50 (kerosene as the solvent) is used instead of the 10% by volume of Cyanex 301 in Example 1. Alkali is added in step S4 to adjust the pH; the amount of alkali used is shown in Table 1. The remaining steps are identical to those in Comparative Example 1. Testing and calculation show that in this comparative example, the zinc extraction rate is 91.63%, and the aluminum extraction rate is 59.68%.

[0059] Comparative Example 2

[0060] This comparative example differs from Example 1 only in the extraction solvent selected in step S4: 10% by volume Cyanex 272 (kerosene as the solvent) is used instead of the 10% by volume Cyanex 301 in Example 1. Alkali is added in step S4 to adjust the pH; the amount of alkali used is shown in Table 1. The remaining steps are identical to those in Comparative Example 1. Testing and calculation show that the zinc extraction efficiency in this comparative example is 99.86%, and the aluminum extraction efficiency is 99.73%.

[0061] Comparative Example 3

[0062] This comparative example differs from Example 1 only in the extraction solvent selected in step S4: 10% by volume of V10 (kerosene as the solvent) is used instead of the 10% by volume of Cyanex 301 in Example 1. Alkali is added in step S4 to adjust the pH; the amount of alkali used is shown in Table 1. The remaining steps are identical to those in Comparative Example 1. Testing and calculation show that the zinc extraction efficiency in this comparative example is 98.73%, and the aluminum extraction efficiency is 99.37%.

[0063] Comparative Example 4

[0064] This comparative example differs from Example 1 only in the extraction solvent selected in step S4: 10% by volume P204 (kerosene as the solvent) is used instead of the 10% by volume Cyanex 301 in Example 1. Alkali is added in step S4 to adjust the pH; the amount of alkali used is shown in Table 1. The remaining steps are identical to those in Comparative Example 1. Testing and calculation show that the zinc extraction efficiency in this comparative example is 90.64%, and the aluminum extraction efficiency is 98.91%.

[0065] Comparative Example 5

[0066] This comparative example differs from Example 1 only in the extraction solvent selected in step S4: 10% by volume of P507 (kerosene as the solvent) is used instead of the 10% by volume of Cyanex 301 in Example 1. Alkali is added in step S4 to adjust the pH; the amount of alkali used is shown in Table 1. The remaining steps are identical to those in Comparative Example 1. Testing and calculation show that in this comparative example, the zinc extraction rate is 98.96%, and the aluminum extraction rate is 100%.

[0067] Comparative Example 6

[0068] This comparative example differs from Example 1 only in the extraction solvent selected in step S4: 10% by volume 336At (kerosene as the solvent) is used instead of the 10% by volume Cyanex 301 in Example 1. Alkali is added in step S4 to adjust the pH. The amount of alkali used is shown in Table 1. The remaining steps are the same as those in Comparative Example 1. Testing and calculation show that the zinc extraction efficiency in this comparative example is 95.19%, and the aluminum extraction efficiency is 0.22%.

[0069] Comparative Example 7

[0070] This comparative example differs from Example 1 only in the extraction solvent selected in step S4: 10% by volume TBP (kerosene as the solvent) is used in place of the 10% by volume Cyanex 301 in Example 1. The remaining steps are identical to those in Comparative Example 1. Testing and calculation show that the zinc extraction efficiency in this comparative example is 9.36%, and the aluminum extraction efficiency is 10.32%.

[0071] Table 1 Table of parameters related to zinc extraction in Example 1 and Comparative Examples 1-7

[0072]

[0073]

[0074] As shown in Table 1, after copper removal, the extractants selected in Example 1 and the comparative examples all had a certain extraction effect on zinc and aluminum in high-pH solutions. Among them, the extractants Cyanex 272, V10, P204, and P507, while simultaneously extracting zinc, also extracted nearly all of the aluminum into the organic phase, failing to separate the zinc and aluminum, and consuming a large amount of alkali during the extraction process. Extractant CLX50 also failed to effectively separate zinc and aluminum, and consumed even more alkali during the extraction process. While extractant 336At was able to extract zinc with a small amount of aluminum extracted, it consumed more alkali than Cyanex 301. Extractant TBP, on the other hand, had unsatisfactory extraction effects on both zinc and aluminum, with a zinc extraction rate of only 9.36%. Therefore, the present invention selected Cyanex 301 as the extractant for zinc extraction, which effectively separates zinc and aluminum while also effectively reducing alkali consumption.

[0075] Comparative Example 8

[0076] This comparative example provides a metal ion extraction method, comprising the following steps:

[0077] S1. Prepare the extraction liquid: the extraction liquid contains Cu 17.07 g / L, Zn 2.03 g / L, Li 0.96 g / L, Rb 0.88 g / L, Cs 0.69 g / L, Ca 0.11 g / L, Sr 2.53 g / L, Ba 1.23 g / L, pH = 2.35.

[0078] S2. Copper Extraction: The extractant obtained in step S1 was extracted using 25% by volume Mextral 984H (kerosene as solvent). The extraction process was a two-stage countercurrent extraction process with a phase ratio (O / A) of 2.5:1 for each extraction stage. The extraction duration for each stage was 3 minutes, and the equilibrium pH during extraction was adjusted to 2-2.5. After the extraction, the phases were separated for 5 minutes to obtain extract phase I (Mextral 984H-loaded organic phase) and raffinate phase I. Raffinate phase I contained 2.2 ppm of copper, and the copper recovery rate was greater than 99.9%.

[0079] S3. Stripping and enriching copper: copper-containing sulfuric acid solution is used as stripping solution to strip the extraction phase I. The stripping solution is prepared from copper sulfate, sulfuric acid and water. The stripping solution contains 35g / L Cu and 180g / L H2SO4. The stripping process is two-stage countercurrent stripping. The stripping ratio (O / A) of each stage of stripping is 1.5:1. The stripping time of each stage of stripping is 3min. After the stripping is completed, copper sulfate solution is obtained, and cathode copper is obtained by electrowinning the copper sulfate solution.

[0080] S4. Zinc extraction: Raffinate phase I was extracted using Cyanex 301 (kerosene as solvent) at a volume concentration of 10%. The pH of raffinate phase I did not need to be adjusted before extraction. The extraction process was a two-stage countercurrent extraction. The extraction phase ratio (O / A) of each stage was 1:1, and the extraction time of each stage was 3 minutes. After the extraction, the phases were separated to obtain extraction phase II (Cyanex 301-loaded organic phase) and raffinate phase II. Raffinate phase II contained 1.46 ppm zinc.

[0081] S5. Stripping and enriching zinc: The extraction phase II was stripped using a 3 mol / L hydrochloric acid solution (solvent: water) with a stripping ratio (O / A) of 1:1. After seven cycles of stripping and enrichment, a zinc chloride solution with a zinc concentration of 14.05 g / L was obtained, wherein the content of the impurity barium was 1.26 g / L, the content of the impurity lithium was 7.0 mg / L, the content of the impurity rubidium was 0.04 g / L, the content of the impurity cesium was <2 mg / L, the content of the impurity calcium was 25 mg / L, and the content of the impurity strontium was 14 mg / L. The recovery rate of zinc was greater than 99.9%. According to calculations, the zinc extraction rate was 99.92%, the barium extraction rate was 12.3%, the lithium extraction rate was 7.6%, the rubidium extraction rate was 6.8%, the cesium extraction rate was 2.9%, the calcium extraction rate was 1.8%, and the strontium extraction rate was 3.9%.

[0082] Comparative Example 8 shows that the extractant Cyanex 301 is not able to effectively separate zinc from barium, lithium, rubidium, strontium, cesium, and calcium. Among them, the extraction rate of calcium is the lowest, at 1.8%, which is still 11 times higher than the extraction rate of aluminum (0.15%) in Example 1. This is difficult to predict for those skilled in the art.

[0083] In summary, the present invention utilizes a step-by-step process to achieve the sequential extraction of metallic copper and zinc, selecting Mextral 984H as the copper extractant and Cyanex 301 as the zinc extractant, thereby extracting copper and zinc from the leachate with high extraction efficiency and high purity. Furthermore, the present invention allows direct in-situ acid leaching of copper-based waste catalysts without pretreatment such as pulverization, effectively reducing energy consumption. The raffinate after copper recovery is directly extracted using the extractant without the need for alkali adjustment, effectively reducing alkali consumption. Furthermore, the present invention features a simple process and utilizes conventional extraction equipment, resulting in low cost and easy operation. It is suitable for use in various factories and can also be applied to the recovery of various copper-based waste catalysts and other CuO / ZnO / Al2O3-based non-methanol catalysts, demonstrating its high applicability.

[0084] The above are only embodiments of the present invention. The invention is not limited to the fields involved in this implementation case. Common knowledge such as the known specific structures and characteristics in the scheme is not described in detail here. Ordinary technicians in the relevant field are aware of all the common technical knowledge in the technical field to which the invention belongs before the application date or priority date, can obtain all the existing technologies in the field, and have the ability to apply conventional experimental means before that date. Ordinary technicians in the relevant field can improve and implement this scheme in combination with their own abilities under the inspiration given by this application. Some typical known structures or known methods should not become obstacles for ordinary technicians in the relevant field to implement this application. It should be pointed out that for those skilled in the art, without departing from the structure of the present invention, several variations and improvements can be made, which should also be regarded as the scope of protection of the present invention. These will not affect the effect of the implementation of the present invention and the practicality of the present invention. 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 extracting and recovering copper and zinc from copper-based waste catalysts, characterized in that: The following steps are involved: S1. Leaching: In-situ leaching of the copper-based spent catalyst using acid to obtain a leachate containing copper, zinc, and aluminum; S2. Copper extraction: extracting the leachate obtained in step S1 using Mextral 984H, and adjusting the equilibrium pH during extraction to 2-2.5 to obtain an extract phase I and a raffinate phase I; S3, stripping and enriching copper: using a copper-containing sulfuric acid solution to strip the extraction phase I to obtain a copper sulfate solution, and then electrowinning the copper sulfate solution to obtain cathode copper; S4, zinc extraction: extracting the raffinate phase I obtained in step S2 using Cyanex 301 to obtain an extract phase II and a raffinate phase II; S5. Back-extraction and zinc enrichment: Use hydrochloric acid solution to back-extract the extraction phase II to obtain zinc chloride solution through enrichment.

2. The method according to claim 1, wherein: In step S1, the acid is one or more of sulfuric acid, hydrochloric acid and nitric acid.

3. The method according to claim 1, wherein: In step S1, the concentration of the acid is 20-100 g / L, the liquid-solid ratio of the leaching is 15-50:1, and the leaching time is 0.5-4 h.

4. The method according to claim 1, wherein: In step S2, the volume concentration of Mextral 984H is 10-30%, the extraction method is countercurrent extraction, the number of extraction stages is 2-4, the extraction phase ratio of each stage is 2-2.5:1, and the extraction time of each stage is 3-10 minutes.

5. The method according to claim 1, wherein: In step S2, after extraction, phase separation is performed to obtain an extract phase I and a raffinate phase I, and the phase separation time is 5 to 10 minutes.

6. The method according to claim 1, wherein: In step S3, the stripping method is countercurrent stripping, the stripping stages are 2 to 4, the stripping ratio of each stage is 1 to 5:1, and the stripping time of each stage is 3 to 8 minutes.

7. The method according to claim 1, wherein: In step S4, the volume concentration of Cyanex 301 is 5-30%, the extraction method is countercurrent extraction, the number of extraction stages is 2-4, the extraction phase ratio of each stage is 1:1-2.5, and the extraction time of each stage is 3-5 minutes.

8. The method according to claim 1, wherein: In step S5 , the stripping phase ratio is 1 to 3:

1.

9. The method according to claim 1, wherein: In step S5 , the concentration of the hydrochloric acid solution is 3 to 6 mol / L.

10. The method according to claim 1, wherein: The raffinate phase II in step S4 serves as one of the sources of acid in step S1.

Images