A copper oxide and its preparation method

Abstract

This invention provides copper oxide and its preparation method, relating to the field of copper oxide preparation technology. The copper oxide of this invention has an approximately hexagonal prism structure. The preparation method involves: precipitating copper from a copper salt solution with oxalic acid and its salt, then dissolving it in an ammonia solution; subsequently, CO2 gas is introduced and aeration is performed to obtain crystalline crystals; and finally, calcination yields the copper oxide of this invention. The copper oxide of this invention exhibits a unique morphology and shows promising application prospects in catalysis, energy, and sensing fields.

Description

Technical Field

[0001] This invention belongs to the field of copper oxide preparation technology, and relates to a copper oxide and its preparation method. Background Technology

[0002] Copper oxide (CuO) is an important functional material with wide applications in electroplating chemicals, gas sensors, batteries, and catalysis. Electronic-grade copper oxide not only requires high purity (≥99%) but also specific morphology requirements; currently, the mainstream market product morphology is primarily spherical micron-sized particles. Copper oxide with unique morphologies offers significant advantages in catalysis, energy, and sensing, providing new solutions to key problems in energy, environmental, and electronic device fields.

[0003] Hexagonal prism-shaped copper oxide is a unique type of copper oxide with a high specific surface area. However, there are currently few publicly available reports on hexagonal prism copper oxide. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides copper oxide and a method for its preparation.

[0005] The technical solution of the present invention is as follows:

[0006] A copper oxide having an approximately hexagonal prism structure, wherein the average side length of the cross-section of the hexagonal prism structure is 2-12 μm, the average length of the hexagonal prism structure is 10-60 μm, and the ratio of the average side length to the average length is 1:1-10.

[0007] The average side length and the average length were measured using a microscope.

[0008] Preferably, the average side length of the cross-section of the hexagonal prism structure is 2-10 μm, the average length of the hexagonal prism structure is 10-50 μm, and the ratio of the average side length to the average length is 1:3-10.

[0009] A method for preparing copper oxide according to any of the above technical solutions includes the following steps:

[0010] S1. Add oxalic acid and its salt solution to copper salt solution to precipitate copper, collect the blue-green precipitate, wash until neutral and dry to obtain copper oxalate.

[0011] S2. Add the copper oxalate obtained in step S1 to an ammonia solution and stir until the precipitate disappears to obtain a copper ammonia solution.

[0012] S3. Pass CO2 gas into the copper ammonia solution obtained in step S2 and aerate until blue-green crystal particles precipitate. Let it stand and age, collect the solid, wash and dry it, and calcine it to obtain the copper oxide.

[0013] Preferably, the copper salt in the copper salt solution in step S1 is selected from one or a combination of two or more of copper chloride, copper sulfate and copper nitrate, and the concentration of copper ions in the copper salt solution is 5-50 g / L.

[0014] Preferably, the molar ratio of copper salt in the copper salt solution and oxalic acid and its salt in the oxalic acid and its salt solution in step S1 is 1:0.5-1.1.

[0015] Preferably, the concentration of oxalic acid and its salt solution in step S1 is 0.1-5 mol / L.

[0016] Preferably, the molar ratio of copper oxalate and NH3 in the ammonia solution in step S2 is 1:3-8.

[0017] Preferably, the CO2 gas introduced in step S3 is introduced until saturation.

[0018] Preferably, the aeration temperature in step S3 is 25-50°C;

[0019] The temperature for static aging in step S3 is 20-40℃, and the time is 4-24h.

[0020] Preferably, the calcination temperature in step S3 is 300-600℃ and the time is 0.5-6h.

[0021] The beneficial effects of this invention are:

[0022] (1) By controlling the nucleation temperature and the amount of crystal precipitation, the intermediate particles obtained by this invention are calcined after being aged at a constant temperature to obtain hexagonal prismatic copper oxide products, which are significantly different from spherical particles. The process is mild and significantly reduces energy consumption compared with conventional high-temperature evaporation deammoniation.

[0023] (2) The copper oxide preparation method of the present invention is suitable for copper-containing waste liquid. By controlling the precipitation rate of copper through precipitation ratio, and by utilizing the difference in solubility of copper oxalate and impurities in ammonia water, impurity metal ions in copper-containing waste liquid can be effectively separated, realizing the high-value utilization of copper-containing waste liquid and improving economic efficiency. Attached Figure Description

[0024] Figure 1 This is a SEM image of copper oxide obtained in Example 1.

[0025] Figure 2 This is a SEM image of copper oxide obtained in Example 1.

[0026] Figure 3 The image shows the XRD pattern of copper oxide obtained in Example 1. Detailed Implementation

[0027] The technical solution of the present invention will be further explained and described below through specific embodiments.

[0028] On the one hand, the present invention proposes a copper oxide having an approximately hexagonal prism structure, wherein the average side length of the cross section of the hexagonal prism structure is 2-12 μm, the average length of the hexagonal prism structure is 10-60 μm, and the ratio of the average side length to the average length is 1:1-10.

[0029] The average side length and average length were measured using a microscope. The average length refers to the longitudinal length of the hexagonal prism structure.

[0030] The copper oxide of this invention has an approximately hexagonal prism structure, wherein the hexagonal cross-section is a regular hexagon or the six sides of the hexagon are not all the same length but are relatively close. The average side length of the cross-section refers to the side length of the hexagon. For example, the average side length can be any value or any value between 2μm, 3μm, 4μm, 5μm, 6μm, 7μm, 8μm, 9μm, 10μm, 11μm, 12μm, etc., without any particular limitation. The average length of the hexagonal prism structure can be any value or any value between 10μm, 15μm, 20μm, 25μm, 30μm, 35μm, 40μm, 45μm, 50μm, 55μm, 60μm, etc., without any particular limitation. The ratio of the average side length to the average length can be any value or any value between 1:1, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9, 1:10, etc., without any particular restrictions.

[0031] Methods for testing particle size include sieving, sedimentation, laser particle size analyzer, electrical resistance method, and microscopy. For the average side length and average length of the approximately hexagonal prism-structured copper oxide of this invention, microscopy is suitable. Microscopy involves directly observing the particle morphology using an optical microscope (OM), scanning electron microscope (SEM), or transmission electron microscope (TEM), and then measuring the particle size using image analysis software. This invention uses SEM microscopy to test the average side length and average length of the copper oxide.

[0032] In some embodiments, the average side length of the cross-section of the hexagonal prism structure is 2-10 μm, the average length of the hexagonal prism structure is 10-50 μm, and the ratio of the average side length to the average length is 1:3-10.

[0033] On the other hand, the present invention also proposes a method for preparing copper oxide according to any of the above-mentioned technical solutions, comprising the following steps:

[0034] S1. Add oxalic acid and its salt solution to copper salt solution to precipitate copper, collect the blue-green precipitate, wash until neutral and dry to obtain copper oxalate.

[0035] S2. Add copper oxalate from step S1 to an ammonia solution and stir until the precipitate disappears to obtain a copper ammonia solution.

[0036] S3. CO2 gas is introduced into the copper ammonia solution in step S2 and aerated until blue-green crystal particles are precipitated. The solution is allowed to stand and age, the solid is collected, washed, dried, and calcined to obtain copper oxide with an approximately hexagonal prism structure.

[0037] In this invention, copper oxalate is obtained by precipitating copper ions with oxalic acid and its salts. The copper oxalate is then reacted with ammonia water to form a copper ammonia solution. CO2 gas is then introduced and aerated until blue-green crystal particles (a complex of basic copper carbonate and basic copper oxalate) precipitate. After calcination and thermal decomposition of the blue-green crystal particles, copper oxide with an approximately hexagonal prism structure is obtained.

[0038] The copper salt solution of this invention can be a high-purity copper salt solution or a copper-containing waste liquid. Copper-containing waste liquid can be waste liquid generated during industrial processes such as metallurgy and mining, electroplating, and metal processing. Besides containing a large amount of copper ions and hydrogen ions, it also contains impurities such as iron, zinc, cadmium, cobalt, and mercury ions. When oxalic acid and its salts precipitate copper ions, the copper ions can be effectively separated from the metal ion impurities in the initial stage. Further dissolution with ammonia and precipitation with CO2 converts some or all of the copper ions in the copper salt solution into hexagonal prism-shaped copper oxide with a special morphology, enabling better resource recovery of the copper-containing waste liquid.

[0039] In some embodiments, the copper salt in the copper salt solution in step S1 is selected from one or a combination of two or more of copper chloride, copper sulfate, and copper nitrate, and the concentration of copper ions in the copper salt solution is 5-50 g / L. For example, the concentration of copper ions in the copper salt solution can be any value or any value between 5 g / L, 15 g / L, 20 g / L, 25 g / L, 30 g / L, 35 g / L, 40 g / L, 45 g / L, 50 g / L, etc., without any particular limitation.

[0040] In some embodiments, the molar ratio of copper salt in the copper salt solution and oxalic acid and its salt solution in step S1 is 1:0.5-1.1. For example, the molar ratio (i.e., precipitation ratio) of copper salt and oxalic acid and its salt can be any value or any value between 1:0.5, 1:0.6, 1:0.7, 1:0.8, 1:0.9, 1:1, etc., without any particular limitation. When the purity of the copper salt solution is high, that is, the metal impurity ions in the solution are few or almost non-existent, the precipitation ratio can be high, such as 1:0.9, 1:0.95, 1:1, etc., which can fully convert the copper salt into copper oxide; when the purity of the copper salt solution is relatively low, such as copper-containing waste liquid, the precipitation ratio can be low, such as 1:0.5, 1:0.6, 1:0.7, etc., which can avoid the precipitation of metal impurity ions, obtain copper oxalate precipitate with high purity, and separate copper ions from impurity metal ions. Even when using copper-containing waste liquid, by controlling the precipitation ratio to obtain copper oxalate precipitate containing a small amount of impurities, copper ions can be further separated from impurity metal ions by dissolving in copper ammonia solution and precipitating again with CO2 gas, thus obtaining high-purity blue-green crystal particles (a complex of basic copper carbonate and basic copper oxalate), achieving the purification of copper ions and obtaining high-purity copper oxide with a hexagonal prism structure.

[0041] There are no particular restrictions on oxalic acid and its salts; they can be oxalic acid, sodium oxalate, ammonium oxalate, potassium oxalate, calcium oxalate, etc.

[0042] In some embodiments, the concentration of oxalic acid and its salt solution in step S1 is 0.1-5 mol / L. For example, the concentration of oxalic acid and its salt solution can be any value or any value between 0.1 mol / L, 0.3 mol / L, 0.5 mol / L, 1 mol / L, 1.5 mol / L, 2 mol / L, 2.5 mol / L, 3 mol / L, 3.5 mol / L, 4 mol / L, 4.5 mol / L, 5 mol / L, etc., without any particular limitation.

[0043] In some embodiments, the molar ratio of copper oxalate and NH3 in the ammonia solution in step S2 is 1:3-8. For example, the molar ratio can be any value or any value between 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, etc., without particular limitation. There is no particular limitation on the concentration of the ammonia solution, which can be 10-29 wt%.

[0044] In some embodiments, the CO2 gas introduced in step S3 is introduced until saturation. Introducing CO2 gas into the copper ammonia solution until saturation is more conducive to the conversion of copper ammonia ions into basic copper carbonate and / or basic copper oxalate, forming blue-green crystal particles.

[0045] In some embodiments, the aeration temperature in step S3 is 25-50°C; aeration is achieved by continuously introducing CO2 gas. For example, the aeration temperature can be any value or any value between 25°C, 30°C, 35°C, 40°C, 45°C, and 50°C, without any particular limitation. Through aeration, the copper ammonia solution can be converted into basic copper carbonate and / or basic copper oxalate relatively completely, achieving effective copper recovery.

[0046] In step S3, the temperature for static aging is 20-40℃, and the time is 4-24 hours. For example, the temperature for static aging can be any value from 20℃, 25℃, 30℃, 35℃, 40℃, or any value in between, without particular restrictions; the time can be any value from 4 hours, 6 hours, 8 hours, 10 hours, 12 hours, 15 hours, 18 hours, 20 hours, 24 hours, or any value in between, without particular restrictions. Specifically, static aging can be 20℃ for 2 hours, 6 hours, 10 hours, 15 hours, 20 hours, etc.; 30℃ for 2 hours, 6 hours, 12 hours, etc.; and 40℃ for 2 hours, 3 hours, 6 hours, etc.

[0047] In some embodiments, the calcination temperature in step S3 is 300-600℃, and the time is 0.5-6h. For example, the calcination temperature can be any value or any value between 300℃, 350℃, 400℃, 450℃, 500℃, 550℃, and 600℃, without particular limitation; the calcination time can be any value or any value between 0.5h, 1h, 2h, 3h, 4h, 5h, and 6h, without particular limitation. Specifically, the calcination conditions can be calcination at 300℃ for 5h, calcination at 400℃ for 4h, calcination at 500℃ for 3h, calcination at 600℃ for 1h, etc.

[0048] The copper oxide of this invention has a special morphology and has good application prospects in catalysis, energy, sensing and other fields.

[0049] The technical solution of the present invention will be further described and illustrated below with reference to various embodiments. Unless otherwise specified, the parts mentioned in the following embodiments are parts by weight.

[0050] Example 1

[0051] Take copper-containing waste liquid from copper smelting electrolyte, where the Cu ion concentration is 15 g / L, the pH is 1.5, and other metal ion impurities (including Zn) are present. 2+ Al 3+ Fe 3+ Mg 2+ Hg 2+The sum of the concentrations of (etc.) does not exceed 1 g / L. A 2 mol / L oxalic acid aqueous solution was added to the above copper-containing waste liquid at a copper ion to oxalic acid molar ratio of 1:0.5 (precipitation ratio of 50%) to precipitate copper, resulting in a blue-green copper oxalate precipitate. After washing until neutral, the precipitate was dried at 50°C.

[0052] Controlling the molar ratio of NH3 to copper in ammonia water to be 4:1, the above-mentioned copper oxalate was slowly added to a 10wt% ammonia solution, and the reaction was stirred until the precipitate disappeared. The solution was a deep blue copper ammonia solution, which was then filtered and set aside for use.

[0053] The above copper ammonia solution was added to a sealed container and high-purity CO2 gas was continuously introduced. The reaction time was controlled at 2 hours. The reaction was continuously aerated at 30°C in a water bath until blue-green crystal particles precipitated. The mixture was then allowed to stand and age at 20°C for another 2 hours.

[0054] The aged solution was separated into solid and liquid phases. The resulting solid product was washed with ultrapure water, dried at 40°C, and then calcined at 300°C for 4 hours to obtain copper oxide.

[0055] The SEM image of copper oxide obtained in this embodiment is attached. Figure 1 and attached Figure 2 As shown, the structure has an approximate hexagonal prism structure. The average side length of the cross-section of the hexagonal prism structure is 2.8 μm, and the average length of the hexagonal prism structure is 18.5 μm, with a ratio of average side length to average length of 1:6.6. The XRD pattern of the copper oxide obtained in this embodiment is attached. Figure 3 As shown, this indicates that copper oxide has a high degree of crystallinity.

[0056] Example 2

[0057] The copper-containing waste liquid is a copper-containing sulfuric acid leaching solution, with a Cu ion concentration of 10 g / L and a pH of 2. Other metal ion impurities (including Zn) are also present. 2+ Al 3+ Fe 3+ Mg 2+ Hg 2+ The sum of the concentrations of (etc.) does not exceed 0.5 g / L. A 1 mol / L sodium oxalate aqueous solution was added to the above copper-containing waste liquid at a copper ion to sodium oxalate molar ratio of 1:0.6 (precipitation ratio of 60%) to precipitate copper, resulting in a blue-green copper oxalate precipitate. After washing until neutral, the precipitate was dried at 50°C.

[0058] Controlling the molar ratio of NH3 to copper in ammonia water to be 5:1, the above-mentioned copper oxalate was slowly added to a 13wt% ammonia solution, and the reaction was stirred until the precipitate disappeared. The solution was a dark blue copper ammonia solution, which was then filtered and set aside for use.

[0059] The above copper ammonia solution was added to a sealed container and high-purity CO2 gas was continuously introduced. The reaction time was controlled at 4 hours. The reaction was continuously aerated at 30°C in a water bath until blue-green crystal particles precipitated. The mixture was then allowed to stand and age at 35°C for 6 hours.

[0060] The aged solution was separated into solid and liquid phases. The resulting solid product was washed with ultrapure water, dried at 60°C, and then calcined at 400°C for 6 hours to obtain copper oxide.

[0061] The copper oxide obtained in this embodiment has an approximately hexagonal prism structure. The average side length of the cross-section of the hexagonal prism structure is 3.5 μm, the average length of the hexagonal prism structure is 17.2 μm, and the ratio of the average side length to the average length is 1:4.9.

[0062] Example 3

[0063] The copper-containing wastewater is copper etching wastewater, with a Cu ion concentration of 25 g / L and a pH of 4. Other metal ion impurities (including Zn) are also present. 2+ Al 3+ Fe 3+ Mg 2+ Hg 2+ The sum of the concentrations of (etc.) does not exceed 0.8 g / L. A 1.5 mol / L calcium oxalate aqueous solution was added to the above copper-containing waste liquid at a copper ion to calcium oxalate molar ratio of 1:0.7 (precipitation ratio of 70%) to precipitate copper, resulting in a blue-green copper oxalate precipitate. After washing until neutral, the precipitate was dried at 50°C.

[0064] Controlling the molar ratio of NH3 to copper in ammonia water to be 5:1, the above-mentioned copper oxalate was slowly added to a 16wt% ammonia solution, and the reaction was stirred until the precipitate disappeared. The solution was a dark blue copper ammonia solution, which was then filtered and set aside for use.

[0065] The above copper ammonia solution was added to a sealed container and high-purity CO2 gas was continuously introduced. The reaction time was controlled at 5 hours. The reaction was continuously aerated at 40°C in a water bath until blue-green crystal particles precipitated. The mixture was then allowed to stand and age at 40°C for 10 hours.

[0066] The aged solution was separated into solid and liquid phases. The resulting solid product was washed with ultrapure water, dried at 60°C, and then calcined at 400°C for 3 hours to obtain copper oxide.

[0067] The copper oxide obtained in this embodiment has an approximately hexagonal prism structure. The average side length of the cross-section of the hexagonal prism structure is 2.2 μm, the average length of the hexagonal prism structure is 15.4 μm, and the ratio of the average side length to the average length is 1:7.

[0068] Example 4

[0069] The copper-containing wastewater is a high-acid, high-iron copper-containing wastewater, with a Cu ion concentration of 50 g / L and a pH of 0. Other metal ion impurities (including Zn) are also present. 2+ Al 3+ Fe 3+ Mg 2+ Hg 2+ The sum of the concentrations of (etc.) does not exceed 2 g / L, Fe 3+ The concentration was 1.3 g / L. A 3 mol / L potassium oxalate aqueous solution was added to the copper-containing waste liquid at a copper ion to potassium oxalate molar ratio of 1:0.8 (precipitation ratio of 80%) to precipitate copper, resulting in a blue-green copper oxalate precipitate. After washing until neutral, the precipitate was dried at 50°C.

[0070] Controlling the molar ratio of NH3 to copper in ammonia water to be 6:1, the above-mentioned copper oxalate was slowly added to a 20wt% ammonia solution, and the reaction was stirred until the precipitate disappeared. The solution was a deep blue copper ammonia solution, which was then filtered and set aside for later use.

[0071] The above copper ammonia solution was added to a sealed container and high-purity CO2 gas was continuously introduced. The reaction time was controlled at 6 hours. The reaction was continuously aerated at 50°C in a water bath until blue-green crystal particles precipitated. The mixture was then allowed to stand and age at 40°C for 12 hours.

[0072] The aged solution was separated into solid and liquid phases. The resulting solid product was washed with ultrapure water, dried at 60°C, and then calcined at 500°C for 2 hours to obtain copper oxide.

[0073] The copper oxide obtained in this embodiment has an approximately hexagonal prism structure. The average side length of the cross-section of the hexagonal prism structure is 4.5 μm, the average length of the hexagonal prism structure is 28.3 μm, and the ratio of the average side length to the average length is 1:6.3.

[0074] Example 5

[0075] The copper-containing wastewater is an electroplating pickling wastewater containing copper, with a Cu ion concentration of 5 g / L, a pH of 0, and other metal ion impurities (including Zn). 2+ Al 3+ Fe 3+ Mg 2+ Hg 2+ The sum of the concentrations of (etc.) does not exceed 0.05 g / L. A 1 mol / L oxalic acid aqueous solution was added to the above copper-containing waste liquid at a copper ion to oxalic acid molar ratio of 1:1 (precipitation ratio of 100%) to precipitate copper, resulting in a blue-green copper oxalate precipitate. After washing until neutral, the precipitate was dried at 50°C.

[0076] Controlling the molar ratio of NH3 to copper in ammonia water to be 4:1, the above-mentioned copper oxalate was slowly added to a 25wt% ammonia solution, and the reaction was stirred until the precipitate disappeared. The solution was a deep blue copper ammonia solution, which was then filtered and set aside for later use.

[0077] The above copper ammonia solution was added to a sealed container and high-purity CO2 gas was continuously introduced. The reaction time was controlled at 6 hours. The reaction was continuously aerated at 50°C in a water bath until blue-green crystal particles precipitated. The mixture was then allowed to stand and age at 35°C for 16 hours.

[0078] The aged solution was separated into solid and liquid phases. The resulting solid product was washed with ultrapure water, dried at 80°C, and then calcined at 600°C for 2 hours to obtain copper oxide.

[0079] The copper oxide obtained in this embodiment has an approximately hexagonal prism structure. The average side length of the cross-section of the hexagonal prism structure is 3.6 μm, the average length of the hexagonal prism structure is 19.7 μm, and the ratio of the average side length to the average length is 1:5.5.

[0080] As described above, the basic principles, main features, and advantages of the present invention have been shown and described. Those skilled in the art should understand that the present invention is not limited to the above embodiments, which are merely preferred embodiments and should not be construed as limiting the scope of the invention. All equivalent changes and modifications made in accordance with the scope of the patent and the description should still fall within the scope of the present invention. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A copper oxide, characterized in that, The copper oxide has an approximately hexagonal prism structure, the average side length of the cross-section of the hexagonal prism structure is 2-12 μm, the average length of the hexagonal prism structure is 10-60 μm, and the ratio of the average side length to the average length is 1:1-10. The average side length and the average length were measured using a microscope.

2. The copper oxide according to claim 1, characterized in that, The average side length of the cross-section of the hexagonal prism structure is 2-10 μm, the average length of the hexagonal prism structure is 10-50 μm, and the ratio of the average side length to the average length is 1:3-10.

3. A method for preparing copper oxide according to claim 1 or 2, characterized in that, Includes the following steps: S1. Add oxalic acid and its salt solution to copper salt solution to precipitate copper, collect the blue-green precipitate, wash until neutral and dry to obtain copper oxalate. S2. Add the copper oxalate obtained in step S1 to an ammonia solution and stir until the precipitate disappears to obtain a copper ammonia solution. S3. Pass CO2 gas into the copper ammonia solution obtained in step S2 and aerate until blue-green crystal particles precipitate. Let it stand and age, collect the solid, wash and dry it, and calcine it to obtain the copper oxide.

4. The method for preparing copper oxide according to claim 3, characterized in that, In step S1, the copper salt in the copper salt solution is selected from one or a combination of two or more of copper chloride, copper sulfate and copper nitrate, and the concentration of copper ions in the copper salt solution is 5-50 g / L.

5. The method for preparing copper oxide according to claim 3, characterized in that, In step S1, the molar ratio of copper salt in the copper salt solution to oxalic acid and its salt in the oxalic acid and its salt solution is 1:0.5-1.

1.

6. The method for preparing copper oxide according to claim 3, characterized in that, The concentration of oxalic acid and its salt solution in step S1 is 0.1-5 mol / L.

7. The method for preparing copper oxide according to claim 3, characterized in that, In step S2, the molar ratio of copper oxalate to NH3 in the ammonia solution is 1:3-8.

8. The method for preparing copper oxide according to claim 3, characterized in that, The step S3 involves introducing CO2 gas until saturation.

9. The method for preparing copper oxide according to claim 3, characterized in that, The aeration temperature in step S3 is 25-50℃; The temperature for static aging in step S3 is 20-40℃, and the time is 4-24h.

10. The method for preparing copper oxide according to claim 3, characterized in that, The calcination temperature in step S3 is 300-600℃, and the time is 0.5-6h.

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