Electronic-grade hollow structure copper oxide and preparation method thereof

Abstract

The present invention provides an electronic-grade hollow-structure copper oxide and a preparation method thereof, belonging to the field of copper oxide preparation. The method comprises: mixing a copper salt with ethylenediaminetetraacetic acid and an auxiliary complexing agent, performing aging and complexation to obtain a complexing solution; dripping a precipitant in stages to the complexing solution for gradient precipitation; and sequentially performing centrifugation, washing, drying, and calcining. The auxiliary complexing agent is an organic carboxylic acid ammonium salt; in the first stage of the gradient precipitation, the temperature is 40°C to 45°C during the dripping step, and the dripping step ends when the pH reaches 5.0 to 5.5; in the second stage, the temperature is raised to 55°C to 60°C during the dripping step, and the dripping step ends when the pH reaches 6.5 to 7.0; in the third stage, the temperature is raised to 70°C to 75°C during the dripping step, and the dripping step ends when the pH reaches 7.5 to 8.0. The present invention utilizes a dual system of ethylenediaminetetraacetic acid and an organic carboxylic acid ammonium salt to complex copper ions, and achieves precursor self-assembly through a staged temperature-controlled gradient precipitation method, thereby producing copper oxide with a three-dimensional through-pore structure without a template.

Description

Technical Field

[0001] The invention belongs to the technical field of copper oxide preparation, and in particular relates to an electronic-grade hollow structure copper oxide and a preparation method thereof. Background Art

[0002] Electronic-grade copper oxide is a high-purity copper oxide widely used in semiconductors, electronic components, and new energy batteries. The purity of electronic-grade copper oxide directly impacts the performance and reliability of the final product, so impurity levels must be strictly controlled during the production process.

[0003] The copper oxide prepared by traditional precipitation + calcination method has low purity (<98%), Fe 3+ 、Na + , K + The metal impurities are high, and the solid copper oxide structure obtained has a small specific surface area (<10m 2 / g), limiting its application in PCB electroplating bath replenishment and catalysis. Currently, the main method for preparing electronic-grade copper oxide is the pyrolysis of high-purity basic copper carbonate or copper-ammine complexes. While this method improves the purity of copper oxide (generally ≥99.5%) compared to copper oxide obtained by conventional copper salt + base reaction followed by thermal decomposition, its purity still needs to be improved, and copper oxide has a relatively small specific surface area, further limiting its application in the high-precision electronics industry. Summary of the Invention

[0004] In view of this, the object of the present invention is to provide an electronic-grade hollow structure copper oxide and a preparation method thereof, aiming to solve at least one technical problem among the background technologies.

[0005] The present invention is achieved in that:

[0006] A first aspect of the present invention provides a method for preparing electronic-grade hollow structure copper oxide, which comprises the following steps:

[0007] The copper salt solution is mixed with the complexing agent and the auxiliary complexing agent in a preset ratio for aging and complexing to obtain a complexing solution;

[0008] adding a precipitant dropwise into the complexing liquid in stages to perform gradient precipitation;

[0009] Centrifugation, washing, drying and calcination are performed in sequence to obtain electronic grade hollow structure copper oxide;

[0010] The complexing agent is ethylenediaminetetraacetic acid; the auxiliary complexing agent is an organic carboxylate ammonium salt; the precipitating agent is an ammonium bicarbonate solution;

[0011] The gradient precipitation is divided into three stages of dropwise addition, and the conditions are controlled as follows:

[0012] The temperature during the first stage of dropwise addition is 40℃~45℃, and the addition is completed until the pH reaches 5.0~5.5;

[0013] In the second stage of dropwise addition, the temperature is raised to 55°C~60°C and the addition is completed until the pH is 6.5~7.0;

[0014] In the third stage of dropwise addition, the temperature is raised to 70°C~75°C and the addition is completed until the pH is 7.5~8.0.

[0015] Furthermore, according to the molar ratio, the copper ion in the copper salt solution: the complexing agent = 1:1-1.2; the copper ion in the copper salt solution: the auxiliary complexing agent = 1:0.15-0.25.

[0016] Furthermore, the organic carboxylate ammonium salt is selected from at least one of ammonium citrate, ammonium tartrate, and ammonium malate.

[0017] Furthermore, the copper salt is selected from at least one of copper nitrate, copper sulfate, and copper acetate, and the concentration of the copper salt solution is 0.3 mol / L to 0.8 mol / L.

[0018] Furthermore, the aging and complexing temperature is 35° C. to 45° C., and the time is 1 hour to 3 hours.

[0019] Furthermore, the dropwise addition rate in the first stage is 100 mL / min to 300 mL / min; the dropwise addition rate in the second stage is 400 mL / min to 600 mL / min; and the dropwise addition rate in the third stage is 50 mL / min to 100 mL / min.

[0020] Furthermore, in the gradient precipitation, aging is performed after the dropwise addition in each stage, and the aging time is 30 min to 90 min.

[0021] Furthermore, the washing is performed using an ethanol solution containing 0.05 mol / L to 0.2 mol / L ammonium acetate, and the number of washing times is ≥2 times.

[0022] Furthermore, the calcination conditions are: in an air atmosphere, heating to 250° C. to 300° C. at a rate of 2° C. / min to 4° C. / min, and keeping the temperature for 1 hour to 3 hours.

[0023] The second aspect of the present invention provides an electronic grade hollow structure copper oxide prepared by the above method, which has a three-dimensional through-hole structure; the purity is ≥99.8%, and the BET specific surface area is ≥50m 2 / g, Fe content ≤10ppm, Na content ≤10ppm, Cl content ≤5ppm.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] 1. The present invention uses a dual complexing agent system consisting of ethylenediaminetetraacetic acid (EDTA) and an organic carboxylic acid ammonium salt to complex copper ions. EDTA controls the nucleation rate, while the organic carboxylic acid ammonium salt is directionally adsorbed to expose the crystal surface. Precursor self-assembly is achieved through a stepwise temperature-controlled gradient precipitation method, avoiding the local supersaturation problem of conventional precipitation. In the absence of a template, copper oxide with a three-dimensional through-pore structure is prepared to form an electronic-grade hollow structure copper oxide.

[0026] 2. The present invention uses ammonium bicarbonate as a precipitant, which performs three functions in sequence under gradient temperature: nucleation control at 40°C → morphology guidance at 60°C → in-situ pore formation at 70°C. This feature cannot be achieved by other precipitants. In addition, the CO2 bubbles generated by the decomposition of ammonium bicarbonate at 70°C-75°C work synergistically with the precipitation process controlled by the gradient temperature to realize the template-free method for preparing hollow structures.

[0027] 3. The method of the present invention is not only environmentally friendly and easy to implement, but also particularly suitable for industrial production applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a flow chart of the method for preparing the electronic-grade hollow structure copper oxide of the present invention;

[0029] Figure 2 This is a TEM image of the electronic-grade hollow structure copper oxide prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific implementation cases described herein are only used to explain the present invention and are not intended to limit the present invention.

[0031] like Figure 1 As shown, a method for preparing electronic-grade hollow structure copper oxide comprises the following steps:

[0032] S1, the copper salt solution is mixed with the complexing agent and the auxiliary complexing agent in a preset ratio for aging and complexing to obtain a complexing solution;

[0033] The copper salt is at least one of copper nitrate, copper sulfate, and copper acetate, preferably copper acetate, and the solution concentration is 0.3 mol / L to 0.8 mol / L;

[0034] The complexing agent is ethylenediaminetetraacetic acid; the auxiliary complexing agent is an organic carboxylic acid ammonium salt, selected from at least one of ammonium citrate, ammonium tartrate, and ammonium malate, preferably ammonium citrate;

[0035] According to the molar ratio, the copper ion in the copper salt solution: the complexing agent = 1:1-1.2; the copper ion in the copper salt solution: the auxiliary complexing agent = 1:0.15-0.25.

[0036] S2, adding the precipitant ammonium bicarbonate (NH4HCO3) solution to the complexing liquid stepwise to perform gradient precipitation;

[0037] The first stage of dropwise addition conditions are: temperature 40℃~45℃, dropwise addition rate 100mL / min~300mL / min, dropwise addition until pH = 5.0~5.5, and then aging for 30min~90min;

[0038] The second stage of dropwise addition conditions are: heating to 55°C~60°C, adding at a rate of 400mL / min~600mL / min, adding until the pH reaches 6.5~7.0, and then aging for 30min~90min.

[0039] The third stage of dropwise addition conditions are: heating to 70°C~75°C, adding at a rate of 50mL / min~100mL / min, adding until the pH reaches 7.5~8.0, and then aging for 30min~90min;

[0040] Ammonium bicarbonate plays three functions in sequence under gradient temperature: nucleation control at 40℃ → morphology guidance at 60℃ → in-situ pore formation at 70℃.

[0041] S3, centrifuging, washing, drying, and calcining in sequence to obtain electronic grade hollow structure copper oxide;

[0042] The washing is carried out with an ethanol solution containing 0.05 mol / L to 0.2 mol / L ammonium acetate, and the number of washing times is ≥ 2 times;

[0043] The calcination conditions are as follows: in an air atmosphere, heating to 250°C~300°C at 2°C / min~4°C / min, and keeping warm for 1h~3h, preferably heating to 280°C at 3°C / min and keeping warm for 2h.

[0044] The electronic grade hollow structure copper oxide prepared by the above preparation method has a three-dimensional through-hole structure; its purity is ≥99.8%, and its BET specific surface area is ≥50m 2 / g, Fe content ≤10ppm, Na content ≤10ppm, Cl content ≤5ppm, can be used to supplement PCB electroplating solution.

[0045] Example 1

[0046] A method for preparing electronic-grade hollow structure copper oxide comprises the following steps:

[0047] S1. Aging and complexation: Mix 0.8 mol / L copper acetate solution with EDTA, then add ammonium citrate (molar ratio of copper acetate: EDTA: ammonium citrate = 1:1.1:0.2); age and complex at 35°C-45°C for 2 h to obtain a complex solution;

[0048] S2. First, the complex liquid was heated to 45°C, and NH4HCO3 solution was added dropwise at a rate of 200 mL / min until the pH reached 5.5, and then matured for 90 minutes; then the temperature was raised to 60°C, and NH4HCO3 solution was added dropwise at a rate of 500 mL / min until the pH reached 7.0, and then matured for 60 minutes; then the temperature was raised to 75°C, and NH4HCO3 solution was added dropwise at a rate of 100 mL / min until the pH reached 8.0, and then matured for 30 minutes;

[0049] S3. The solid product of S2 was centrifuged and washed twice with ammonium acetate-ethanol solution (containing 0.2 mol / L ammonium acetate), then dried, and finally heated to 280°C at 3°C / min in air atmosphere and calcined for 2 h to obtain electronic grade hollow structure copper oxide. Its TEM image is shown as follows: Figure 2 shown.

[0050] Example 2

[0051] A method for preparing electronic-grade hollow structure copper oxide comprises the following steps:

[0052] S1. Aging and complexation: Mix 0.8 mol / L copper acetate solution with EDTA, then add ammonium citrate, copper nitrate: EDTA: ammonium tartrate = 1:1.5:0.15 (molar ratio); age and complex at 35°C-45°C for 2 h to obtain a complex solution;

[0053] S2. First, the complex liquid was heated to 45°C, and NH4HCO3 solution was added dropwise at a rate of 200 mL / min until the pH reached 5.5, and then matured for 90 minutes; then the temperature was raised to 60°C, and NH4HCO3 solution was added dropwise at a rate of 500 mL / min until the pH reached 7.0, and then matured for 60 minutes; then the temperature was raised to 75°C, and NH4HCO3 solution was added dropwise at a rate of 100 mL / min until the pH reached 8.0, and then matured for 30 minutes;

[0054] S3. The reaction product of S2 was centrifuged to obtain a solid, which was washed twice with an ammonium acetate-ethanol solution (containing 0.2 mol / L ammonium acetate), then dried, and finally heated to 250°C at 3°C / min in an air atmosphere and calcined for 2 h to obtain electronic-grade hollow structure copper oxide.

[0055] Example 3

[0056] A method for preparing electronic-grade hollow structure copper oxide comprises the following steps:

[0057] S1. Aging and complexation: Mix 0.8 mol / L copper acetate solution with EDTA, then add ammonium citrate in a molar ratio of copper sulfate:EDTA:ammonium malate = 1:1:0.25; age and complex at 35°C-45°C for 2 h to obtain a complex solution;

[0058] S2. First, the complex liquid was heated to 45°C, and NH4HCO3 solution was added dropwise at a rate of 200 mL / min until the pH reached 5.5, and then matured for 90 minutes; then the temperature was raised to 60°C, and NH4HCO3 solution was added dropwise at a rate of 500 mL / min until the pH reached 7.0, and then matured for 60 minutes; then the temperature was raised to 75°C, and NH4HCO3 solution was added dropwise at a rate of 100 mL / min until the pH reached 8.0, and then matured for 30 minutes;

[0059] S3. The reaction product of S2 was centrifuged to obtain a solid, which was washed twice with an ammonium acetate-ethanol solution (containing 0.2 mol / L ammonium acetate), then dried, and finally heated to 300°C at 3°C / min in an air atmosphere and calcined for 2 h to obtain electronic-grade hollow structure copper oxide.

[0060] Example 4

[0061] In this embodiment, based on Example 1, the temperature during the first stage of dropwise addition in step S2 is adjusted to 43°C, the temperature during the second stage of dropwise addition is adjusted to 57°C, and the temperature during the third stage of dropwise addition is adjusted to 72°C. Other steps and conditions are consistent with Example 1.

[0062] Example 5

[0063] In this embodiment, based on Example 1, the temperature during the first stage of dropwise addition in step S2 is adjusted to 40°C, the temperature during the second stage of dropwise addition is adjusted to 55°C, and the temperature during the third stage of dropwise addition is adjusted to 70°C. Other steps and conditions are consistent with Example 1.

[0064] Example 6

[0065] In this embodiment, based on the embodiment 1, the first stage of step S2 is added dropwise until the pH value is 5.2, the second stage is added dropwise until the pH value is 6.7, and the third stage is added dropwise until the pH value is 7.7. The other steps and conditions are the same as those in the embodiment 1.

[0066] Example 7

[0067] In this embodiment, based on the embodiment 1, the first stage of step S2 is added dropwise until pH=5.0, the second stage is added dropwise until pH=6.5, and the third stage is added dropwise until pH=7.5. Other steps and conditions are consistent with those in embodiment 1.

[0068] Comparative Example 1

[0069] This comparative example is based on Example 1, except that the auxiliary complexing agent in step S1 is deleted, and the other steps and conditions are the same as those in Example 1.

[0070] Comparative Example 2

[0071] In this comparative example, based on Example 1, the dropping temperature in step S2 was all controlled to room temperature, and the other steps and conditions were consistent with Example 1.

[0072] Comparative Example 3

[0073] In this comparative example, based on Example 1, the gradient precipitation in step S2 was adjusted to a one-time precipitation; the other steps and conditions were consistent with those in Example 1.

[0074] The specific steps of comparative example S2 are as follows: the complex liquid is heated to 75° C., and NH 4 HCO 3 solution is added dropwise at a rate of 100 mL / min until the pH reaches 8.0, followed by aging for 120 min.

[0075] Comparative Example 4

[0076] In this comparative example, based on Example 1, the gradient precipitation in step S2 was adjusted to a two-stage precipitation of front and back; the other steps and conditions were consistent with those in Example 1.

[0077] The specific steps of comparative example S2 are as follows: first, the complex liquid is heated to 45°C, and NH4HCO3 solution is added dropwise at a rate of 200 mL / min until the pH reaches 5.5, and then the solution is aged for 90 minutes; then, the complex liquid is heated to 75°C, and NH4HCO3 solution is added dropwise at a rate of 100 mL / min until the pH reaches 8.0, and then the solution is aged for 90 minutes.

[0078] Comparative Example 5

[0079] In this comparative example, based on Example 1, the gradient precipitation in step S2 was adjusted to a two-stage precipitation of middle and last stages; the other steps and conditions were consistent with those in Example 1.

[0080] The specific steps of comparative example S2 are as follows: first, the complex liquid is heated to 60°C, and NH4HCO3 solution is added dropwise at a rate of 500 mL / min until the pH reaches 7.0, and then the mixture is aged for 90 minutes; then, the complex liquid is heated to 75°C, and NH4HCO3 solution is added dropwise at a rate of 100 mL / min until the pH reaches 8.0, and then the mixture is aged for 30 minutes.

[0081] The products obtained in Examples 1 to 7 and Comparative Examples 1 to 5 were tested for CuO purity, impurity content, and specific surface area. The results are shown in Table 1.

[0082] Table 1

[0083]

[0084] As can be seen from the data in Table 1, the copper oxide prepared in the embodiment of the present invention has the advantages of high purity, low impurities, and large specific surface area, and can be used as electronic-grade copper oxide in the high-precision electronics industry.

[0085] Comparison of Comparative Example 1 with Example 1 shows that, during aging and complexation, the auxiliary complexing agent, the organic carboxylic acid ammonium salt, is deleted, resulting in decreased purity, increased impurity content, and a slight decrease in specific surface area of ​​the copper oxide obtained. This indicates that the copper oxide performance is far lower than that of Example 1.

[0086] Comparison of Comparative Example 2 with Example 1 shows that when the precipitant is added dropwise at room temperature during the gradient precipitation in step S2, the purity of the copper oxide obtained decreases slightly, the impurity content increases slightly, but the specific surface area decreases significantly. This shows that the performance of the copper oxide is much lower than that of Example 1.

[0087] Comparison of Comparative Example 3 with Example 1 shows that when the precipitant is added dropwise in one step in step S2, the purity of the copper oxide obtained decreases, the impurities increase, and the specific surface area decreases significantly. This shows that the performance of the copper oxide is much lower than that of Example 1.

[0088] Comparing Comparative Examples 4 and 5 with Example 1, it can be seen that when step S2 adopts the two-stage addition of the precipitant in the front + back or middle + back stages, the purity of the copper oxide obtained decreases slightly, the impurities increase slightly, and the specific surface area decreases significantly. It can be seen that the copper oxide performance is much lower than that of Example 1.

[0089] The above-described embodiments merely illustrate several implementations of the present invention, and while their descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

Claims

1. A method for preparing electronic grade hollow structure copper oxide, characterized in that: The preparation method comprises the following steps: The copper salt solution is mixed with the complexing agent and the auxiliary complexing agent in a preset ratio for aging and complexing to obtain a complexing solution; adding a precipitant dropwise into the complexing liquid in stages to perform gradient precipitation; Centrifugation, washing, drying and calcination are performed in sequence to obtain electronic grade hollow structure copper oxide; The complexing agent is ethylenediaminetetraacetic acid; the auxiliary complexing agent is organic carboxylic acid ammonium salt; the precipitant is ammonium bicarbonate solution; The gradient precipitation is divided into three stages of dropwise addition, and the conditions are controlled as follows: The temperature during the first stage of dropwise addition is 40℃~45℃, and the addition is completed until the pH reaches 5.0~5.5; In the second stage of dropwise addition, the temperature is raised to 55°C~60°C and the addition is completed until the pH is 6.5~7.0; In the third stage, the temperature is raised to 70°C~75°C and the addition is completed until the pH is 7.5~8.

0.

2. The method for preparing an electronic-grade hollow structure copper oxide according to claim 1, wherein: According to the molar ratio, the copper ion in the copper salt solution: the complexing agent = 1:1-1.2; the copper ion in the copper salt solution: the auxiliary complexing agent = 1:0.15-0.

25.

3. The method for preparing an electronic grade hollow structure copper oxide according to claim 1, wherein: The organic carboxylic acid ammonium salt is selected from at least one of ammonium citrate, ammonium tartrate and ammonium malate.

4. The method for preparing an electronic-grade hollow structure copper oxide according to claim 1, wherein: The copper salt is selected from at least one of copper nitrate, copper sulfate, and copper acetate, and the concentration of the copper salt solution is 0.3 mol / L to 0.8 mol / L.

5. The method for preparing an electronic-grade hollow structure copper oxide according to claim 1, wherein: The temperature of the aging complexation is 35° C. to 45° C., and the time is 1 hour to 3 hours.

6. The method for preparing an electronic-grade hollow structure copper oxide according to claim 1, wherein: The dropping rate of the first stage is 100 mL / min to 300 mL / min; the dropping rate of the second stage is 400 mL / min to 600 mL / min; and the dropping rate of the third stage is 50 mL / min to 100 mL / min.

7. The method for preparing an electronic grade hollow structure copper oxide according to claim 1, wherein: In the gradient precipitation, aging is performed after the dropwise addition of each stage, and the aging time is 30 min to 90 min.

8. The method for preparing an electronic-grade hollow structure copper oxide according to claim 1, wherein: The washing is performed using an ethanol solution containing 0.05 mol / L to 0.2 mol / L ammonium acetate, and the number of washing times is ≥2 times.

9. The method for preparing an electronic grade hollow structure copper oxide according to claim 1, wherein: The calcination conditions are: in an air atmosphere, heating to 250° C. to 300° C. at a rate of 2° C. / min to 4° C. / min, and keeping the temperature for 1 hour to 3 hours.

10. An electronic grade hollow structure copper oxide, characterized in that: It is prepared by the preparation method of an electronic grade hollow structure copper oxide according to any one of claims 1 to 9; the copper oxide has a three-dimensional through-hole structure; its purity is ≥99.8%, and its BET specific surface area is ≥50m 2 / g, Fe content ≤10ppm, Na content ≤10ppm, Cl content ≤5ppm.

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