Recycling treatment method based on industrial waste catalyst copper-chromium catalyst

Abstract

The invention discloses a recycling treatment method based on an industrial waste catalyst copper-chromium catalyst, and belongs to the technical field of industrial solid waste regeneration. According to the method, the industrial waste catalyst and sodium carbonate are adopted to generate chromium salt; then acid liquor produced in the electrolysis process serves as a copper leaching agent to be recycled, it is guaranteed that no waste water is generated in the copper recycling treatment process, auxiliary materials and energy consumption are reduced, and the treatment cost is reduced; when the regenerant is obtained, insoluble substances are filtered to obtain a pure sodium thiosulfate solution, sodium thiosulfate salt is obtained through concentration and crystallization, no waste water is generated in the chromium recovery treatment process, meanwhile, byproducts are generated, and the treatment cost is reduced. The method has the characteristics of simple process flow, easy control of reaction conditions, low production cost, high recovery rate of copper and chromium, high resource utilization rate, high product quality, high comprehensive utilization rate, energy conservation, emission reduction and the like, and the recovery rate reaches more than 98.5%.

Description

Technical Field

[0001] The present invention belongs to the technical field of industrial solid waste regeneration, and in particular relates to a method for recycling and utilizing industrial waste catalyst copper-chromium catalyst. Background Art

[0002] Industrial catalysts are catalytic objects composed of catalytic substances that are mixed, formed, calcined and activated and supported on a carrier. During use, due to carbon deposition, metal sintering, pollutant deposition and loss of catalytic substances, the catalyst activity declines and becomes deactivated, turning into waste catalysts.

[0003] In the production of furfuryl alcohol, 1,600-1,800 tons of spent catalyst are currently discharged annually. According to investigations, this spent catalyst contains 45% copper oxide and 40% chromium trioxide. Chemical analysis of the waste residue after organic matter recovery reveals that it contains 28%-32% Cr(III) (calculated as Cr2O3) (including approximately 2% hexavalent chromium), 38%-42% Cu(II) (calculated as CuO), and the remaining impurities include approximately 10% SiO2 and <10% various polymers. Due to carbon deposition, contaminant deposition, or metal sintering, the separation and recovery technology for this spent catalyst is further complicated. Consequently, the waste catalyst problem has long remained unresolved, becoming a major problem for furfuryl alcohol manufacturers. The perennial discharge of spent catalysts not only pollutes the environment but also wastes valuable resources. Furthermore, the high chromium oxide content in these solid wastes poses a serious threat to the ecological environment.

[0004] Prior art CN1062023C reports a method for separating and recovering copper and chromium from industrial waste catalysts. The waste catalyst is first alkalized with caustic soda, then calcined in a high-temperature reverberatory furnace at 800°C to 1000°C. The calcined material is leached with water to separate the chromium from the copper. Sodium chromate is recovered from the leached solution, and the copper oxide-containing precipitate is acidified to produce copper salts. The recovered product meets the GB437-80 product standard, with copper and chromium recovery rates of 85% and 90%, respectively. The chromium-containing slag is both a hazardous waste and a recyclable secondary resource. This technology, which uses high-temperature calcination, not only consumes a lot of energy but also suffers from high pollution, a single recovery method, low purity, and a low recovery rate.

[0005] Due to the shortage of chromium resources, it can replace limestone, dolomite and other raw materials in industrial production, which can achieve the purpose of saving resources and reducing energy consumption. It is very necessary to improve the comprehensive utilization of various forms of chromium in chromium slag. Therefore, it is urgent to further improve the recycling, resource utilization and harmless recovery of industrial waste copper-chromium catalysts. Summary of the Invention

[0006] To address the technical issues of low copper and chromium metal recovery rates and purity in the prior art, the first objective of the present invention is to provide a method for regenerating and treating copper-chromium catalysts from industrial waste catalysts. This method utilizes industrial waste catalysts and sodium carbonate to generate chromium salts. The acid solution produced during the electrolysis process is then recycled as a copper leaching agent. This not only ensures that the copper recovery process does not generate wastewater, but also reduces auxiliary materials and energy consumption, thereby lowering disposal costs. When the regenerated product is obtained, the insoluble matter is filtered to obtain a pure sodium thiosulfate solution, which is then concentrated and crystallized to obtain sodium thiosulfate salt. This chromium recovery process does not generate wastewater, but also produces byproducts, thereby reducing disposal costs.

[0007] The second purpose of the present invention is to provide a recycling and utilization method for industrial waste catalyst copper-chromium catalyst, which has a simple process flow, easy control of reaction conditions, low production cost, high copper-chromium recovery rate of more than 98.5%, and high resource utilization.

[0008] The present invention is achieved through the following technical solutions:

[0009] A method for recycling and utilizing industrial waste copper-chromium catalyst comprises the following steps:

[0010] S1, select industrial waste catalyst and sodium carbonate, mix them evenly, and place them in a roasting furnace for sodium roasting to obtain calcine;

[0011] S2. Selecting calcine, grinding it, leaching it with heated water, filtering and washing it to obtain a first filtrate and a first filter residue;

[0012] S3, adding a leaching agent to the first filter residue for leaching treatment, filtering and washing to obtain a second filtrate and a second filter residue;

[0013] S4, adding hydrogen peroxide to the second filtrate for purification, adjusting the pH to 3.8-4.0, and filtering to obtain a third filtrate and a third filter residue;

[0014] S5, electrolytically treating the third filtrate with an electrolytic device to obtain cathode copper and copper electrolytic solution;

[0015] S6, adding a reducing agent to the first filtrate for reduction treatment, filtering and washing, to obtain a fourth filter residue and a fourth filtrate;

[0016] S7, performing oxidation treatment on the fourth filtrate, filtering out insoluble matter, concentrating and crystallizing to obtain a regenerated product;

[0017] The regenerated product is sodium thiosulfate salt.

[0018] Preferably, in S1, the mixing mass ratio of industrial waste catalyst to sodium carbonate is 1:0.8-1.1;

[0019] The temperature of the sodium calcination treatment is 700-800° C., and the calcination time is 3-4 hours.

[0020] Preferably, in S2, the particle size after roasting and grinding is 100-120 mesh;

[0021] The temperature of the hot water is 90-100°C; the leaching time of the heated water is 2-3 hours;

[0022] The volume of the hot water is 5000-5500 ml.

[0023] Preferably, in S3, the leaching agent includes dilute sulfuric acid or copper electrodeposition solution;

[0024] The molar concentration of the dilute sulfuric acid is 1.0 to 1.5 mol / l;

[0025] The dilute sulfuric acid leaching time is 2 to 3 hours;

[0026] The ratio of the mass of the first filter residue to the volume of the leaching agent is 1:5.

[0027] The copper electrowinning solution is derived from the material obtained after the electrowinning treatment in step S5 and can be used for recycling in the treatment process.

[0028] Preferably, in S4, the volume ratio of the second filtrate to hydrogen peroxide is 1000:5;

[0029] The purification treatment takes 2 to 3 hours.

[0030] As a preference, in said S5, 180-220A / m is used. 2 The electrolytic treatment is carried out for 24 hours.

[0031] Preferably, in S6, the first filtrate is sodium chromate filtrate;

[0032] The reducing agent is sulfur;

[0033] The mass ratio of the volume of the first filtrate to the reducing agent is 1:0.3;

[0034] The reduction treatment lasts for 2 to 3 hours at a temperature of 85 to 90°C.

[0035] Preferably, the oxidation treatment process of the fourth filtrate in S7 is as follows: adding sulfur to the fourth filtrate and filling it with air to react;

[0036] The reaction time is 2 to 3 hours.

[0037] The reaction equation in this application scheme is:

[0038] 1. Step 1: Use industrial waste catalyst and sodium carbonate to generate chromium salt at a high temperature of 700℃-800℃:

[0039] 2Cr2O3+4Na2CO3→4Na2CrO4+3CO2+O2

[0040] 2. In step 3, dilute sulfuric acid is used to react with the copper oxide in the water-leached residue to produce copper sulfate. The rust residue produced by the iron tools in the sodium roasting process reacts with sulfuric acid to produce ferrous sulfate. The chromium oxide roasted at high temperature does not react with dilute sulfuric acid.

[0041] CuO +H2SO4→CuSO4+H2O

[0042] FeO +H2SO4=FeSO4+H2O

[0043] 3. Step 4: using hydrogen peroxide to oxidize the divalent iron in the acid leaching solution into trivalent iron and adding alkali to adjust the pH to generate ferric hydroxide precipitate.

[0044] 2Fe 2+ +H2O2+2H + =2Fe 3 +2H2O

[0045] Fe 3+ +3H2O=Fe(OH)3↓+3H +

[0046] 4. In step 5, the copper sulfate solution obtained by purification in step 4 is electrolyzed in step 5 to generate a cathode copper product. The electrolyte generated in the electrolysis process is used as the leaching agent (leaching copper acid) in step 3 to achieve recycling. The copper recovery and disposal process does not generate wastewater, reduces auxiliary materials and energy consumption, and reduces disposal costs.

[0047] Cu 2+ +2e→Cu

[0048] H2O-2e=2H + +1 / 2O2

[0049] 5. The sodium chromate filtrate in step 6 is reduced with a reducing agent to obtain pure chromium hydroxide precipitate.

[0050] 4Na2CrO4+6S+7H2O=4Cr(OH)3↓+3Na2S2O3+2NaOH

[0051] 6. Through step 7, the filtrate of the precipitated chromium hydroxide is treated with sulfur to convert the free NaOH in the reaction solution into Na2S2O3 and Na2S, and the Na2S is further converted into Na2S2O3 using air. The reaction formulas are:

[0052] 6 NaOH +6S→Na2S2O3+2Na2S+3H2O

[0053] 2Na2S+3O2→2Na2S2O3

[0054] Compared with the prior art, the present invention has at least the following technical effects:

[0055] (1) The present invention provides a recycling and utilization method based on an industrial waste catalyst copper-chromium catalyst, in which industrial waste catalyst and sodium carbonate are used to generate chromium salt; then the acid solution produced in the electrolysis process is recycled as a copper leaching agent, which not only ensures that the copper recovery and disposal process does not generate wastewater, reduces auxiliary materials and energy consumption, and reduces disposal costs; when obtaining the regenerated product, insoluble matter is filtered to obtain a pure sodium thiosulfate solution, which is concentrated and crystallized to obtain sodium thiosulfate salt. The chromium recovery and disposal process does not generate wastewater, but also produces by-products, thereby reducing disposal costs.

[0056] (2) In this regeneration treatment method, during the copper regeneration process, the acid is recycled, and during the chromium regeneration process, no wastewater is discharged, and by-products are produced, which basically achieves the maximum rational utilization of resources. At the same time, through cathode copper and chromium hydroxide products, chromium hydroxide is used to make trivalent chromium salts and chromium trioxide, chemical reagents, and is also used in paint pigments and wool processing, further improving product recycling.

[0057] (3) After the treatment method based on the recycling and utilization of industrial waste catalyst copper-chromium catalyst, the copper recovery rate is not less than 98.5%, the chromium recovery rate is not less than 99%, the cathode copper content is not less than 99.9%, and the chromium hydroxide content is not less than 98%.

[0058] (4) This method for recycling and utilizing industrial waste copper-chromium catalysts features a simple process flow, easily controlled reaction conditions, low production costs, and a high copper-chromium recovery rate exceeding 98.5%, resulting in high resource utilization. This method not only recovers a large amount of valuable resources but also significantly reduces environmental pollution from waste copper-chromium catalysts, providing an industrially valuable approach to pollution control for waste catalyst manufacturers. The method is simple to operate, inexpensive, and requires minimal investment. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] Figure 1 The figure is a flow chart of the steps of the recycling and treatment method based on industrial waste catalyst copper-chromium catalyst;

[0060] Figure 2 Schematic diagram of the specific processing method of Example 3. DETAILED DESCRIPTION

[0061] The embodiments of the present invention will be described in detail below with reference to the examples. However, those skilled in the art will understand that the following examples are only used to illustrate the present invention and should not be construed as limiting the scope of the present invention. Specific conditions not specified in the examples are carried out according to conventional conditions or conditions recommended by the manufacturer. Reagents or instruments used without indicating the manufacturer are all conventional products that can be purchased commercially.

[0062] The washing solution described below is distilled water.

[0063] Example 1:

[0064] S1. Add 1 kg of spent catalyst to 1 kg of sodium carbonate in a 1:1 mass ratio, heat to 750°C and calcine for 3 hours. After cooling, 2036 g of calcine was obtained.

[0065] S2. Add 5000 ml of pure water to 2036 g of calcined sand and heat to 95 ° C for 2 hours. After the reaction, filter and wash the filter cake with 1000 ml of washing liquid to obtain 5650 ml of the first filtrate and 871 g of the first filter residue (40% moisture equivalent to 522.3 g on a dry basis).

[0066] S3. 871g of the first filter residue was leached with 5000ml of dilute sulfuric acid (1.1mol / L). After the reaction, the filter cake was washed with 200ml of washing liquid to obtain 5475ml of the second filtrate and 178.3g of the second filter residue (40% moisture, equivalent to 107g on a dry basis).

[0067] S4. 5475 ml of the second filtrate was added to 27.38 ml of hydrogen peroxide to adjust the pH to about 3.8 and reacted at 80 ° C for 2 hours for purification. After the reaction, the mixture was filtered and the filter cake was washed with 20 ml of washing solution to obtain 5490 ml of the third filtrate and 15.2 g of the third filter residue (40% moisture, equivalent to 9.1 g on a dry basis).

[0068] S5. Place 5490 ml of the third filtrate into an electrolysis device and pass a direct current at 180 A / m 2 Electrowinning was carried out to obtain 5400 ml of copper electrowinning solution and 283 g of cathode copper.

[0069] S6. 5650 ml of the first filtrate was placed in a reactor, 448.3 g of sulfur was added, and the temperature was raised to 90 ° C. and the reaction was reacted for 2 hours. After the reaction was completed, it was filtered and washed with pure water to obtain 1603 g of chromium hydroxide precipitate (40% moisture, equivalent to 962 g on a dry basis) and 5010 ml of the fourth filtrate.

[0070] S7. 149.4 g of sulfur was added to 5010 ml of the fourth filtrate and air was introduced to react for 2 hours, followed by concentration and crystallization. 960.3 g of sodium thiosulfate salt (with 5 crystal water equivalent to 614.6 g on a dry basis) was obtained by filtration.

[0071] Example 2:

[0072] S1. Add 1.1 kg of sodium carbonate to 1 kg of spent catalyst in a mass ratio of 1:1.1, heat to 750 ° C and calcine for 3 hours. After cooling, 2040.3 g of calcine was obtained.

[0073] S2. Add 5000 ml of pure water to 2040.3 g of calcined sand and heat to 95 ° C. and stir for 2 hours. After the reaction, filter and wash the filter cake with 1000 ml of washing liquid to obtain 5652 ml of the first filtrate and 869 g of the first filter residue (40% moisture equivalent to 521.2 g on a dry basis).

[0074] S3. 869g of the first filter residue was added with 5000ml of copper electrodeposition solution (1.5mol / L) and leached for 2 hours. After the reaction was completed, the filter was filtered and the filter cake was washed with 200ml of washing solution to obtain 5480ml of the second filtrate and 172.2g of the second filter residue (40% moisture equivalent to 103.3g on a dry basis).

[0075] S4. 5480 ml of the second filtrate was added with 27.4 ml of hydrogen peroxide to adjust the pH to about 3.8 and reacted at 80 ° C for 2 hours for purification. After the reaction, the filter was filtered and the filter cake was washed with 20 ml of washing solution to obtain 5478 ml of the third filtrate and 10.9 g of the third filter residue (40% moisture, equivalent to 6.5 g on a dry basis).

[0076] S5. Place 5478 ml of the second filtrate into an electrolysis device and pass a direct current at 180 A / m 2 Electrowinning was carried out to obtain 5400 ml of copper electrowinning solution and 318 g of cathode copper.

[0077] S6. 5652 ml of the first filtrate was placed in a reactor, 450 g of sulfur was added, and the temperature was raised to 90 ° C. and the reaction was reacted for 2 hours. After the reaction was completed, it was filtered and washed with pure water to obtain 1609.8 g of chromium hydroxide precipitate (40% moisture, equivalent to 965.9 g on a dry basis) and 5008 ml of the third filtrate.

[0078] S7. 150 g of sulfur was added to 5008 ml of the third filtrate and air was introduced to react for 2 hours, followed by concentration and crystallization. 774 g of sodium thiosulfate (with 5 hydrates of crystallization equivalent to 617.1 g on a dry basis) was obtained by filtration.

[0079] Example 3: Specific implementation process is as follows Figure 2 As shown:

[0080] S1. Add 1 kg of spent catalyst to 1 kg of sodium carbonate in a 1:1 mass ratio, heat to 800°C and calcine for 3 hours. After cooling, 2043 g of calcine was obtained.

[0081] S2. Add 5000 ml of pure water to 2043 g of calcined sand and heat to 95 ° C. The mixture is stirred for 2 hours. After the reaction is completed, the mixture is filtered and the filter cake is washed with 1000 ml of washing liquid to obtain 5652 ml of the first filtrate and 869 g of the first filter residue (40% moisture, equivalent to 521.2 g on a dry basis).

[0082] S3. Add 5000 ml of copper electrodeposition solution (1.5 mol / L) to 869 g of the first filter residue and leach for 2 hours. After the reaction is completed, filter and wash the filter cake with 200 ml of washing liquid to obtain 5480 ml of the second filtrate and 172.2 g of the second filter residue (40% moisture equivalent to 102.2 g on a dry basis).

[0083] S4. 5480 ml of the second filtrate was added with 27.4 ml of hydrogen peroxide to adjust the pH to about 3.8 and reacted at 80 ° C for 2 hours for purification. After the reaction, the filter was filtered and the filter cake was washed with 20 ml of washing solution to obtain 5478 ml of the third filtrate and 5.8 g of the third filter residue (40% moisture, equivalent to 3.5 g on a dry basis).

[0084] S5. Place 5478 ml of the second filtrate into an electrolysis device and pass a direct current at 220 A / m 2 Electrowinning was carried out to obtain 5400 ml of copper electrowinning solution and 318 g of cathode copper.

[0085] S6. 5652 ml of the first filtrate was placed in a reactor, 450 g of sulfur was added, and the temperature was raised to 90 ° C. and the reaction was reacted for 2 hours. After the reaction was completed, it was filtered and washed with pure water to obtain 1610 g of chromium hydroxide precipitate (40% moisture, equivalent to 966 g on a dry basis) and 5008 ml of the third filtrate.

[0086] S7. 151 g of sulfur was added to 5008 ml of the third filtrate and air was introduced to react for 2 hours, followed by concentration and crystallization. 774 g of sodium thiosulfate (with 5 hydrates of crystallization equivalent to 495.3 g on a dry basis) was obtained by filtration.

[0087] Comparative Example 1:

[0088] S1. 1 kg of spent catalyst was added with 0.9 kg of sodium carbonate in a mass ratio of 1:0.9, heated to 750 ° C and calcined for 3 hours. After cooling, 1927 g of calcine was obtained.

[0089] S2. Add 5000 ml of pure water to 1929 g of calcined sand and heat to 95 ° C for 2 hours. After the reaction, filter and wash the filter cake with 1000 ml of washing liquid to obtain 5632 ml of the first filtrate and 919 g of the first filter residue (40% moisture equivalent to 551.3 g on a dry basis).

[0090] S3. 919g of the first filter residue was added to 5000ml of copper electrodeposition solution (1.5mol / L) for leaching. After the reaction was completed, the filter was filtered and the filter cake was washed with 200ml of washing solution to obtain 5434ml of the second filtrate and 334g of the second filter residue (40% moisture equivalent to 133.4g on a dry basis).

[0091] S4. 5434 ml of the second filtrate was added to 27.20 ml of hydrogen peroxide to adjust the pH to about 3.8 and reacted at 80 ° C for 2 hours for purification. After the reaction, the filter was filtered and the filter cake was washed with 200 ml to obtain 5592 ml of the third filtrate and 105 g of the third filter residue (40% moisture equivalent to 63 g on a dry basis).

[0092] S5. Place 5592 ml of the second filtrate into an electrolysis device and pass a direct current at 220 A / m 2 Electrowinning was carried out to obtain 5500 ml of copper electrowinning solution and 313 g of cathode copper.

[0093] S6. 5632 ml of the first filtrate was placed in a reactor, 408 g of sulfur was added, and the temperature was raised to 90 ° C. and the reaction was reacted for 2 hours. After the reaction was completed, it was filtered and washed with pure water to obtain 1458 g of chromium hydroxide precipitate (40% moisture, equivalent to 875 g on a dry basis) and 5048 ml of the third filtrate.

[0094] S7. 136 g of sulfur was added to 5048 ml of the third filtrate and air was introduced to react for 2 hours, and concentrated and crystallized to obtain 698 g of sodium thiosulfate (with 5 crystal water equivalent to 447 g on dry basis) by filtration.

[0095] Comparative Example 2:

[0096] S1. Add 1 kg of spent catalyst to 1 kg of sodium carbonate in a 1:1 mass ratio, heat to 750°C and calcine for 3 hours. After cooling, 2035.5 g of calcine was obtained.

[0097] S2. Add 5000 ml of pure water to 2045 g of calcined sand and heat to 95 ° C for 2 hours. After the reaction, filter and wash the filter cake with 1000 ml of washing liquid to obtain 5650 ml of the first filtrate and 871 g of the first filter residue (40% moisture equivalent to 522.5 g on a dry basis).

[0098] S3. 871g of the first filter residue was leached with 5000ml of dilute sulfuric acid (1.1mol / L). After the reaction, the filter cake was washed with 200ml of washing liquid to obtain 5475ml of the second filtrate and 185g of the second filter residue (40% moisture, equivalent to 111g on a dry basis).

[0099] S4. 5475 ml of the second filtrate was added to 27.38 ml of hydrogen peroxide to adjust the pH to about 3.8 and reacted at 80 ° C for 2 hours for purification. After the reaction, the filter was filtered and the filter cake was washed with 20 ml of washing liquid to obtain 5490 ml of the third filtrate and 8.3 g of the third filter residue (40% moisture equivalent to 5 g on a dry basis).

[0100] S5. Place 5490 ml of the second filtrate into an electrolysis device and pass direct current at 220 AA / m 2 Electrowinning was carried out to obtain 5400g of copper electrowinning solution and 318g of cathode copper.

[0101] S6. 5650 ml of the first filtrate was placed in a reactor, 452 g was added, and the temperature was raised to 90 ° C. The reaction was allowed to proceed for 2 hours. After the reaction was completed, the precipitate of chromium hydroxide was obtained by filtering and washing with pure water.

[0102] S7. 151 g of sulfur was added to the third filtrate and air was introduced to react for 2 hours, followed by concentration and crystallization to obtain 495.3 g of sodium thiosulfate salt by filtration.

[0103] Comparative Example 3:

[0104] S1. Add 1 kg of spent catalyst to 1 kg of sodium carbonate in a 1:1 mass ratio, heat to 750°C and calcine for 2 hours. After cooling, 2035.5 g of calcine was obtained.

[0105] S2. Add 5000 ml of pure water to 2045 g of calcined sand and heat to 95 ° C for 2 hours. After the reaction, filter and wash the filter cake with 1000 ml of washing liquid to obtain 5650 ml of the first filtrate and 871 g of the first filter residue (40% moisture equivalent to 522.5 g on a dry basis).

[0106] S3. 871g of the first filter residue was leached with 5000ml of copper electrodeposition solution (1.5mol / L). After the reaction was completed, the filter cake was washed with 200ml of washing solution to obtain 5475ml of the second filtrate and 185g of the second filter residue (40% moisture equivalent to 111g on a dry basis).

[0107] S4. 5475 ml of the second filtrate was added to 27.38 ml of hydrogen peroxide to adjust the pH to about 3.8 and reacted at 80 ° C for 2 hours for purification. After the reaction, the filter was filtered and the filter cake was washed with 20 ml of washing liquid to obtain 5490 ml of the third filtrate and 8.3 g of the third filter residue (40% moisture equivalent to 5 g on a dry basis).

[0108] S5. Place 5490 ml of the third filtrate into an electrolysis device and pass a direct current at 180 A / m 2 Electrowinning was performed to obtain 5400 ml of copper electrowinning solution and 281.3 g of cathode copper.

[0109] S6. 5650 ml of the first filtrate was placed in a reactor, 448.3 g of sulfur was added, and the temperature was raised to 90 ° C. and the reaction was reacted for 2 hours. After the reaction was completed, it was filtered and washed with pure water to obtain 1603 g of chromium hydroxide precipitate (40% moisture, equivalent to 962 g on a dry basis) and 5010 ml of the fourth filtrate.

[0110] S7. 149.4 g of sulfur was added to 5010 ml of the fourth filtrate and air was introduced to react for 2 hours, followed by concentration and crystallization. 768 g of sodium thiosulfate salt (with 5 crystal water equivalent to 491.5 g on a dry basis) was obtained by filtration.

[0111] Table 1 Comparison results of various embodiments and comparative examples

[0112] Craftsmanship Copper recovery rate % Chromium recovery rate (%) Cathode copper (wt%) Chromium hydroxide (wt%) Example 1 98.0 99.2 99.92 98.1 Example 2 98.5 99.6 99.93 98.0 Example 3 98.6 99.6 99.91 97.9 Comparative Example 1 96.0 90.2 99.92 98.0 Comparative Example 2 98.5 99.6 99.91 98.0 Comparative Example 3 99.5 90.2 99.91 98.0

[0113] Conclusion comparison:

[0114] The results in the table show that: Example 1 is compared with Comparative Example 1: the recovery rate of chromium is 90.2%, which is 9% lower than that of Example 1. After analysis and calculation, the amount of sodium carbonate used in the sodium roasting of Comparative Example 1 is reduced, resulting in a decrease in the recovery rate of chromium. The conversion rate of chromium trioxide to chromate during the sodium roasting process is reduced. Compared with Example 1 and Comparative Example 3, the sodium roasting time of Comparative Example 3 is reduced by 1 hour, and the conversion rate of chromium trioxide to chromate is also reduced.

[0115] This recycling and treatment method has a simple process flow, easily controllable reaction conditions, low production costs, and a high copper and chromium recovery rate of over 98.5%. During the copper regeneration process, the acid is recycled, and during the chromium regeneration process, no wastewater is discharged while producing byproducts, essentially achieving the maximum rational utilization of resources. This high resource utilization rate not only recovers a large amount of valuable resources but also significantly reduces environmental pollution caused by spent copper and chromium catalysts, providing an industrially valuable approach to pollution control for waste catalyst manufacturers. The method is simple to operate, low in cost, and requires minimal investment.

[0116] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention shall be included in the scope of protection of the present invention.

Claims

1. A method for recycling industrial waste copper-chromium catalyst, characterized in that: The steps include: S1, select industrial waste catalyst and sodium carbonate, mix them evenly, and place them in a roasting furnace for sodium roasting to obtain calcine; S2, selecting calcine, grinding, leaching with heated water, filtering and washing to obtain a first filtrate and a first filter residue; S3, adding a leaching agent to the first filter residue for leaching treatment, filtering and washing to obtain a second filtrate and a second filter residue; S4, adding hydrogen peroxide to the second filtrate for purification, adjusting the pH to 3.8-4.0, and filtering to obtain a third filtrate and a third filter residue; S5, electrolyzing the third filtrate using an electrolytic device to obtain cathode copper and copper electrolytic solution; S6, adding a reducing agent to the first filtrate for reduction treatment, filtering and washing, to obtain a fourth filter residue and a fourth filtrate; S7, performing oxidation treatment on the fourth filtrate, filtering out insoluble matter, concentrating and crystallizing to obtain a regenerated product; The regenerated product is sodium thiosulfate salt.

2. The method for recycling industrial waste copper-chromium catalyst according to claim 1, characterized in that: In said S1, the mixing mass ratio of industrial waste catalyst to sodium carbonate is 1:0.8-1.1; The temperature of the sodium calcination treatment is 700-800° C., and the calcination time is 3-4 hours.

3. The method for recycling industrial waste copper-chromium catalyst according to claim 1, characterized in that: In said S2, the particle size after roasting and grinding is 100-120 mesh; The temperature of the hot water is 90-100°C; the leaching time of the heated water is 2-3 hours; The volume of the hot water is 5000-5500 ml.

4. The method for recycling industrial waste copper-chromium catalyst according to claim 1, characterized in that: In said S3, said leaching agent comprises dilute sulfuric acid or copper electrodeposition solution; The molar concentration of the dilute sulfuric acid is 1.0 to 1.5 mol / l; The dilute sulfuric acid leaching time is 2 to 3 hours; The volume ratio of the mass of the first filter residue to the leaching agent is 1:

5.

5. The method for recycling industrial waste copper-chromium catalyst according to claim 1, characterized in that: In S4, the volume ratio of the second filtrate to hydrogen peroxide is 1000:5; The purification treatment takes 2 to 3 hours.

6. The method for recycling industrial waste copper-chromium catalyst according to claim 1, characterized in that: In the above S5, 180~220A / m is used. 2 The electrolytic treatment is carried out for 24 hours.

7. The method for recycling industrial waste copper-chromium catalyst according to claim 1, characterized in that: In said S6, said first filtrate is sodium chromate filtrate; The reducing agent is sulfur; The mass ratio of the volume of the first filtrate to the reducing agent is 1:0.3; The reduction treatment lasts for 2 to 3 hours at a temperature of 85 to 90°C.

8. The method for recycling industrial waste copper-chromium catalyst according to claim 1, characterized in that: In said S7, the oxidation process of the fourth filtrate is as follows: adding sulfur to the fourth filtrate and filling it with air to react; The reaction time is 2 to 3 hours.

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