Method for recovering highly active copper oxide from alkaline etching waste liquid based on ammonia distillation method

Abstract

The present invention provides a method for recovering highly active copper oxide from alkaline etching waste liquid based on an ammonia distillation method, and belongs to the field of resource recovery of copper-containing waste liquid. The method comprises the following steps: filtering the alkaline etching waste liquid to remove suspended matter; dimethylglyoxime-diatomaceous earth adsorption coupled impurity removal; the etching waste liquid after impurity removal is subjected to a gradient ammonia distillation treatment combining normal pressure ammonia distillation and negative pressure ammonia distillation to obtain a crude basic copper carbonate product; the crude basic copper carbonate product is dissolved in a urea solution to obtain a tetraammine copper carbonate solution; a secondary negative pressure ammonia distillation treatment is performed to obtain a fine basic copper carbonate product with a spherical honeycomb structure; graded calcination and water vapor activation are synergistically treated to obtain highly active copper oxide. The present invention combines dimethylglyoxime-diatomaceous earth coupled impurity removal, gradient ammonia distillation, urea dissolution + secondary ammonia distillation and graded calcination + water vapor activation treatment processes to improve the quality and performance of copper oxide products, obtain highly active copper oxide powder for PCB electroplating, and realize efficient recycling of copper resources.

Description

Technical Field

[0001] The invention belongs to the technical field of resource treatment of copper-containing waste liquid, and in particular relates to a method for recovering highly active copper oxide from alkaline etching waste liquid based on an ammonia evaporation method. Background Art

[0002] Etching is an essential step in the circuit board manufacturing process. The purpose of etching is to remove the unprotected non-conductive copper on the patterned circuit board to form the circuit. Etching includes inner layer etching and outer layer etching. The inner layer is etched with acid, and the outer layer is etched with alkaline. The alkaline etching solution is ammonium chloride + copper chloride + ammonia water + etching salt. The etching process of the circuit board produces a large amount of copper-ammonia complexes (such as [Cu(NH3)4] 2+ ) of alkaline etching waste liquid. Since the waste liquid contains high copper content, if it is not treated and discharged directly, it will cause serious harm to the environment.

[0003] Traditional recovery methods (such as neutralization precipitation and electrolysis) have problems such as low purity, high energy consumption or ammonia pollution. Although the ammonia evaporation method can release copper ions, direct precipitation is difficult to meet the requirements of electronic-grade copper oxide for PCB electroplating (purity ≥99.5%, specific surface area ≥30m 2 / g) requirements. Summary of the Invention

[0004] In view of this, the object of the present invention is to provide a method for recovering highly active copper oxide from alkaline etching waste liquid based on ammonia evaporation method, aiming to solve at least one technical problem among the background technology.

[0005] The present invention is achieved in that:

[0006] A method for recovering highly active copper oxide from alkaline etching waste liquid based on an ammonia distillation method comprises the following steps:

[0007] Filtering alkaline etching waste liquid to remove suspended matter;

[0008] Dimethylglyoxime-diatomaceous earth adsorption coupling removal of impurities;

[0009] The etching waste liquid after impurities removal is subjected to a gradient ammonia distillation treatment combining normal pressure ammonia distillation and negative pressure ammonia distillation to obtain a crude basic copper carbonate product;

[0010] The crude basic copper carbonate is dissolved in a urea solution to obtain a tetraammine copper carbonate solution;

[0011] The secondary negative pressure ammonia distillation treatment produces a spherical honeycomb structure of basic copper carbonate fine product;

[0012] Highly active copper oxide is obtained by synergistically treating the fine basic copper carbonate through graded calcination and steam activation.

[0013] Furthermore, the dimethylglyoxime-diatomaceous earth adsorption coupling impurity removal step specifically includes:

[0014] Adjusting the pH of the filtered etching waste liquid to a weak alkaline state;

[0015] Add 0.1wt%-0.3wt% dimethylglyoxime to the weakly alkaline etching waste liquid and stir at room temperature for 20min-40min to precipitate the Ni impurities;

[0016] After solid-liquid separation, the solution passes through a diatomaceous earth dynamic adsorption tower at a flow rate of 2BV / h~3BV / h to adsorb colloids and organic impurities.

[0017] Furthermore, the pH value of the weakly alkaline etching waste liquid is 8.0-8.2.

[0018] Furthermore, the step of subjecting the impurity-removed etching waste liquid to a gradient ammonia distillation treatment combining atmospheric pressure ammonia distillation and negative pressure ammonia distillation specifically comprises:

[0019] Evaporate ammonia at atmospheric pressure at 80-95°C until the ammonia concentration is less than 20%;

[0020] Ammonia is evaporated under negative pressure at 60°C-70°C and a vacuum degree of -0.08MPa~-0.05MPa to remove residual ammonia and obtain a crude basic copper carbonate product;

[0021] Wash with ethanol and water to remove impurity ions adsorbed on the surface.

[0022] Furthermore, according to the molar ratio, urea: basic copper carbonate = 4~6:1;

[0023] The temperature at which the crude basic copper carbonate is dissolved in the urea solution is 70°C to 90°C;

[0024] The concentration of the urea solution is 20wt%~30wt%.

[0025] Furthermore, the temperature of the secondary negative pressure ammonia evaporation is 85° C. to 95° C., and the vacuum degree is -0.03 MPa to -0.01 MPa.

[0026] Furthermore, the step of co-processing the high-quality basic copper carbonate by graded calcination and water vapor activation specifically includes: putting the dried high-quality basic copper carbonate into a microwave calcination furnace, and performing gradient calcination and activation treatment in an air atmosphere.

[0027] Furthermore, the gradient calcination activation treatment specifically includes:

[0028] Heat to 200°C~300°C at the first heating rate and keep warm for 0.5h~1.5h;

[0029] The temperature is raised to 400° C. to 500° C. at a second heating rate, 2 wt % to 4 wt % of water vapor is introduced into the microwave calcining furnace, and the temperature is maintained for 0.5 h to 1.5 h to obtain highly active copper oxide.

[0030] Furthermore, the first heating rate is 4°C / min to 6°C / min; and the second heating rate is 8°C / min to 12°C / min.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] 1. The present invention combines dimethylglyoxime-diatomaceous earth coupled impurity removal, gradient ammonia evaporation, urea dissolution + secondary ammonia evaporation, and graded calcination + water vapor activation treatment processes to improve the quality and performance of copper oxide products, significantly reduce the time required for acid dissolution, obtain highly active copper oxide powder for PCB electroplating, and achieve efficient recycling of copper resources.

[0033] 2. The method of the present invention is not only environmentally friendly but also easy to implement and suitable for industrial production applications.

[0034] 3. The copper oxide prepared by the present invention has the advantages of uniform particle size, high purity, few impurities, large specific surface area, and fast acid dissolution rate, and can be used as high-activity copper oxide with excellent performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 The present invention is a flow chart of a method for recovering highly active copper oxide from alkaline etching waste liquid based on ammonia distillation method;

[0036] Figure 2 This is a particle size distribution diagram of copper oxide prepared in Example 1 of the present invention;

[0037] Figure 3 This is a SEM image of the copper oxide prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0038] 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.

[0039] like Figure 1 As shown, a method for recovering highly active copper oxide from alkaline etching waste liquid based on ammonia evaporation method includes steps S1 to S6.

[0040] S1, filtering the alkaline etching waste liquid to remove suspended matter;

[0041] The main components of PCB alkaline etching waste liquid include copper ammonia complex, free ammonia, chloride, additives (such as oxidants, organic corrosion inhibitors, organic stabilizers, etc.) and metal impurities (such as nickel Ni 2+ Mainly), due to its complex composition, it is very easy to form scum during homogenization in the regulating tank, which is not conducive to subsequent treatment. Therefore, the PCB alkaline etching waste liquid is first filtered and pre-treated to remove suspended matter.

[0042] S2, dimethylglyoxime-diatomaceous earth adsorption coupling removal;

[0043] (1) Adjusting the pH of the filtered etching waste liquid to a weak alkaline state, specifically pH = 8.0-8.2; weak alkaline conditions are conducive to the subsequent removal of metal impurities by dimethylglyoxime;

[0044] (2) Add 0.1wt%-0.3wt% dimethylglyoxime (DMG) to the weak alkaline etching waste liquid and stir at room temperature for 20min~40min to precipitate the Ni impurities; the presence of copper ammonia complex and free ammonia in the PCB alkaline etching waste liquid inhibits the reaction between copper ions and dimethylglyoxime. Under the condition of adding a trace amount of dimethylglyoxime, it preferentially reacts with Ni 2+ The reaction generates a chelate compound to precipitate Ni(DMG)2;

[0045] (3) After solid-liquid separation, the solution passes through a diatomaceous earth dynamic adsorption tower at a flow rate of 2BV / h~3BV / h to further adsorb colloids and organic impurities; the diatomaceous earth dynamic adsorption tower can effectively remove colloidal particles and some organic matter in PCB alkaline etching waste liquid.

[0046] S3, gradient ammonia distillation treatment combining normal pressure ammonia distillation and negative pressure ammonia distillation to obtain crude basic copper carbonate;

[0047] (1) Evaporate ammonia at atmospheric pressure at 80°C to 95°C until the ammonia concentration is less than 20%;

[0048] (2) Perform negative pressure ammonia evaporation at 60°C~70°C and -0.08MPa~-0.05MPa vacuum to remove residual ammonia;

[0049] (3) The solid product obtained by vacuum ammonia evaporation is washed with ethanol and water to remove impurity ions adsorbed on the surface and obtain crude basic copper carbonate.

[0050] S4, preparing a tetraamminecopper carbonate solution;

[0051] The molar ratio of urea to basic copper carbonate is 4-6:1, preferably 5:1. The temperature for dissolving the crude basic copper carbonate in the urea solution is 70°C-90°C, preferably 80°C. The concentration of the urea solution is 20wt%-30wt%. The present invention uses urea instead of liquid ammonia or a carbonated ammonia solution to dissolve the crude basic copper carbonate, resulting in controlled release of ammonia and avoiding the high risk of direct use of liquid ammonia. This makes the process safer, and the absence of acid or alkali makes it more environmentally friendly.

[0052] S5, secondary negative pressure ammonia evaporation: Under the conditions of 85℃~95℃ and vacuum degree of -0.03MPa~-0.01MPa, the tetraamminecopper carbonate solution prepared in S4 is subjected to secondary negative pressure ammonia evaporation treatment to obtain a spherical honeycomb structured basic copper carbonate fine product; the solution is heated under negative pressure to volatilize free ammonia, destroy the balance of the copper-ammine complex, and promote the re-precipitation of copper in the form of high-purity basic copper carbonate. At the same time, volatile impurities (such as residual ammonia and organic amines) are removed.

[0053] S6, graded calcination + steam activation synergistically treats the fine basic copper carbonate to obtain highly active copper oxide;

[0054] The dried basic copper carbonate product is put into a microwave calcining furnace and subjected to gradient calcination activation treatment in an air atmosphere.

[0055] Gradient calcination activation treatment specifically includes:

[0056] Raise the temperature to 200°C~300°C at a heating rate of 4°C / min~6°C / min, and keep warm for 0.5h~1.5h, preferably 1h;

[0057] The temperature is raised to 400°C~500°C at a heating rate of 8°C / min~12°C / min, and water vapor is introduced into the microwave calcining furnace in an amount of 2wt%~4wt% of the fine basic copper carbonate. The temperature is kept for 0.5h~1.5h, preferably 1h, to obtain highly active copper oxide.

[0058] The copper recovery rate of the present invention is ≥98%, the purity of copper oxide is ≥99.5%, and the Cl content is less than 10ppm;

[0059] The copper oxide prepared by the present invention has a controllable particle size distribution and a specific surface area of ​​30 m 2 / g, 10g CuO completely dissolves in 200mL 10% dilute sulfuric acid in ≤10s, which meets the performance requirements of high-activity copper oxide for PCB electroplating.

[0060] Example 1

[0061] A method for recovering highly active copper oxide from alkaline etching waste liquid based on an ammonia distillation method comprises the following steps:

[0062] S1, filtering the alkaline etching waste liquid to remove suspended matter.

[0063] S2, adjusting the pH of the etching waste liquid treated in S1 to 8.1; adding 0.2wt% dimethylglyoxime, stirring at room temperature for 30 minutes, and after solid-liquid separation, passing the solution through a diatomaceous earth dynamic adsorption tower at a flow rate of 2.5BV / h to further adsorb colloids and organic impurities.

[0064] S3, first, performing atmospheric ammonia evaporation at 90°C to evaporate the ammonia concentration to less than 20%; then, performing vacuum ammonia evaporation at 65°C and a vacuum degree of -0.06 MPa to remove residual ammonia; finally, washing the solid product obtained by vacuum ammonia evaporation with ethanol and water to remove impurity ions adsorbed on the surface, thereby obtaining crude basic copper carbonate.

[0065] S4, preparing a urea solution at a concentration of 25 wt%, adding a certain amount of crude basic copper carbonate to the urea solution at a urea: basic copper carbonate = 5:1 (molar ratio), heating to 80° C. for dissolution to obtain a tetraamminecopper carbonate solution.

[0066] S5, a secondary negative pressure ammonia evaporation treatment is carried out under the conditions of a temperature of 90°C and a vacuum degree of -0.02MPa to obtain a fine basic copper carbonate with a spherical honeycomb structure.

[0067] S6, the basic copper carbonate product obtained in S5 is dried, and then placed in a microwave calcining furnace. In an air atmosphere, the temperature is first increased to 250°C at a heating rate of 5°C / min and kept warm for 1 hour; then the temperature is increased to 450°C at a heating rate of 10°C / min, 3wt% water vapor is introduced into the microwave calcining furnace, and kept warm for 1 hour to obtain highly active copper oxide, whose particle size distribution is as follows Figure 2 As shown, its SEM is as Figure 3 shown.

[0068] Example 2

[0069] A method for recovering highly active copper oxide from alkaline etching waste liquid based on an ammonia distillation method comprises the following steps:

[0070] S1, filtering the alkaline etching waste liquid to remove suspended matter.

[0071] S2, adjusting the pH of the etching waste liquid treated in S1 to 8.0; adding 0.3wt% dimethylglyoxime, stirring at room temperature for 40 minutes, and after solid-liquid separation, passing the solution through a diatomaceous earth dynamic adsorption tower at a flow rate of 3BV / h to further adsorb colloids and organic impurities.

[0072] S3, first, performing atmospheric ammonia evaporation at 80°C to evaporate the ammonia concentration to less than 20%; then, performing vacuum ammonia evaporation at 60°C and a vacuum degree of -0.08 MPa to remove residual ammonia; finally, washing the solid product obtained by vacuum ammonia evaporation with ethanol and water to remove impurity ions adsorbed on the surface, thereby obtaining crude basic copper carbonate.

[0073] S4, preparing a urea solution at a concentration of 30 wt%, adding a certain amount of crude basic copper carbonate to the urea solution at a molar ratio of urea to basic copper carbonate = 4:1, heating to 70° C. for dissolution to obtain a tetraamminecopper carbonate solution.

[0074] S5, a secondary negative pressure ammonia evaporation treatment is carried out under the conditions of a temperature of 85°C and a vacuum degree of -0.02MPa to obtain a fine basic copper carbonate with a spherical honeycomb structure.

[0075] S6. Dry the fine basic copper carbonate obtained in S5, then put it into a microwave calcining furnace. First, heat it to 200°C at a heating rate of 4°C / min in an air atmosphere and keep it warm for 1 hour. Then, heat it to 400°C at a heating rate of 8°C / min. Pass 2wt% water vapor into the microwave calcining furnace and keep it warm for 1 hour to obtain highly active copper oxide.

[0076] Example 3

[0077] A method for recovering highly active copper oxide from alkaline etching waste liquid based on an ammonia distillation method comprises the following steps:

[0078] S1, filtering the alkaline etching waste liquid to remove suspended matter.

[0079] S2, adjusting the pH of the etching waste liquid treated in S1 to 8.2; adding 0.1wt% dimethylglyoxime, stirring at room temperature for 40 minutes, and after solid-liquid separation, passing the solution through a diatomaceous earth dynamic adsorption tower at a flow rate of 3BV / h to further adsorb colloids and organic impurities.

[0080] S3, first, performing atmospheric ammonia evaporation at 80°C to evaporate the ammonia concentration to less than 20%; then, performing vacuum ammonia evaporation at 70°C and a vacuum degree of -0.05 MPa to remove residual ammonia; finally, washing the solid product obtained by vacuum ammonia evaporation with ethanol and water to remove impurity ions adsorbed on the surface, thereby obtaining crude basic copper carbonate.

[0081] S4, preparing a urea solution at a concentration of 20 wt%, adding a certain amount of crude basic copper carbonate to the urea solution at a molar ratio of urea: basic copper carbonate = 6:1, and heating to 90° C. to dissolve the mixture to obtain a tetraamminecopper carbonate solution.

[0082] S5, a secondary negative pressure ammonia evaporation treatment is carried out under the conditions of a temperature of 95°C and a vacuum degree of -0.02MPa to obtain a fine basic copper carbonate with a spherical honeycomb structure.

[0083] S6. Dry the fine basic copper carbonate obtained in S5, then put it into a microwave calcining furnace. First, heat it to 300°C at a heating rate of 6°C / min in an air atmosphere and keep it warm for 1 hour. Then, heat it to 500°C at a heating rate of 12°C / min, introduce 4wt% water vapor into the microwave calcining furnace, and keep it warm for 1 hour to obtain highly active copper oxide.

[0084] Comparative Example 1

[0085] In this comparative example, based on Example 1, the gradient ammonia evaporation process in step S3 was adjusted to single atmospheric pressure ammonia evaporation, and the other steps and conditions were the same as those in Example 1.

[0086] In this comparative example, step S3 specifically comprises: performing atmospheric ammonia evaporation at 90° C. to remove ammonia; and washing the solid product obtained by vacuum ammonia evaporation with ethanol and water to remove impurity ions adsorbed on the surface, thereby obtaining a crude basic copper carbonate product.

[0087] Comparative Example 2

[0088] In this comparative example, based on Example 1, the gradient ammonia evaporation process in step S3 was adjusted to single negative pressure ammonia evaporation, and the other steps and conditions were the same as those in Example 1.

[0089] In this comparative example, step S3 specifically comprises: performing vacuum ammonia evaporation at 65° C. and a vacuum degree of −0.06 MPa to remove ammonia; and washing the solid product obtained by vacuum ammonia evaporation with ethanol and water to remove impurity ions adsorbed on the surface, thereby obtaining a crude basic copper carbonate product.

[0090] Comparative Example 3

[0091] This comparative example is based on Example 1, except that step S2 is deleted, and the other steps and conditions are the same as those in Example 1.

[0092] Comparative Example 4

[0093] In this comparative example, based on Example 1, the urea in step S4 is replaced by liquid ammonia solution, and the other steps and conditions are consistent with those in Example 1.

[0094] Comparative Example 5

[0095] In this comparative example, based on Example 1, the gradient calcination in step S6 is replaced by a single-stage calcination, and the other steps and conditions are the same as those in Example 1.

[0096] In this comparative example, step S6 is specifically as follows: drying the basic copper carbonate product obtained in S5, then putting it into a microwave calcining furnace, heating it to 450°C at a heating rate of 10°C / min under an air atmosphere, introducing 3wt% water vapor into the microwave calcining furnace, and keeping the temperature for 2h to obtain copper oxide.

[0097] Comparative Example 6

[0098] This comparative example is based on Example 1, except that 3 wt % of water vapor is not introduced during the gradient calcination in step S6. Other steps and conditions are the same as those in Example 1.

[0099] The products obtained in Examples 1 to 3 and Comparative Examples 1 to 6 were tested for CuO purity, specific surface area, and impurity Cl content, respectively, and their acid dissolution rates were measured. The acid dissolution rate was determined by measuring the time required for 10 g of the test product to completely dissolve in 200 mL of 10% dilute sulfuric acid. The longer the time, the slower the acid dissolution rate. The results are shown in Table 1. The acid dissolution rate directly reflects the activity of the copper oxide: a faster acid dissolution rate indicates higher activity, and a slower acid dissolution rate indicates lower activity.

[0100] Table 1

[0101]

[0102] From the data in Table 1, it can be seen that the copper oxide product prepared in the embodiment of the present invention has a purity of ≥99.5%, a Cl content of less than 10 ppm, and a specific surface area of ​​≥30 m 2 / g, and the acid dissolution rate is fast, which meets the performance requirements of high-activity electronic copper oxide used in electronic industries such as PCB electroplating.

[0103] Comparing Comparative Example 1 and Comparative Example 2 with Example 1, respectively, it can be seen that when ammonia evaporation in S3 is carried out at a single atmospheric pressure or negative pressure, the purity of the copper oxide product obtained decreases and the Cl content increases, the time required for acid dissolution increases to more than 15 seconds, and the specific surface area decreases significantly. It can be seen that the purity and activity of the copper oxide products obtained in Comparative Examples 1 and 2 are lower than those in Example 1.

[0104] Comparing Comparative Example 3 with Example 1, it can be seen that when the dimethylglyoxime-diatomaceous earth adsorption coupled impurity removal method in step S2 is omitted, the time required for acid dissolution and the specific surface area of ​​the resulting product do not change significantly, but the purity of the copper oxide decreases significantly and the Cl content increases significantly. It can be seen that the purity of the copper oxide product produced in Comparative Example 3 is significantly lower than that of Example 1.

[0105] Comparing Comparative Example 4 with Example 1, it can be seen that when the urea in S4 is replaced by liquid ammonia solution, the purity of the obtained copper oxide product decreases slightly and the Cl content increases, the time required for acid dissolution increases, and the specific surface area decreases significantly. It can be seen that the activity of the copper oxide product obtained in Comparative Example 4 is lower than that in Example 1.

[0106] Comparing Comparative Example 5 with Example 1, it can be seen that when the gradient calcination in step S6 is replaced by a single-stage calcination, the purity of the copper oxide product obtained does not change significantly, the Cl content increases slightly, but the specific surface area decreases, and the time required for acid dissolution increases. It can be seen that the activity of the copper oxide product obtained in Comparative Example 5 is significantly lower than that in Example 1.

[0107] Comparison of Comparative Example 6 with Example 1 shows that, without introducing water vapor for activation treatment during calcination, the purity of the copper oxide product obtained is almost unchanged, the Cl content increases slightly, but the time required for acid dissolution increases, and the specific surface area decreases significantly. It can be seen that the copper oxide product obtained in Comparative Example 6 has lower activity than that in Example 1.

[0108] In the electronics industry such as PCB electroplating, electronic copper oxide is required to have high activity, high purity, low chlorine and other properties. The copper oxide prepared in Comparative Examples 1 to 6 is difficult to meet the above performance requirements.

[0109] 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 recovering highly active copper oxide from alkaline etching waste liquid based on ammonia distillation, characterized in that: The method comprises the following steps: (1) Filter the alkaline etching waste liquid to remove suspended matter; (2) Dimethylglyoxime-diatomaceous earth adsorption coupling impurity removal; specifically, the following steps are used: adjusting the pH of the filtered etching waste liquid to a weak alkaline state; adding 0.1wt%-0.3wt% dimethylglyoxime to the weakly alkaline etching waste liquid, stirring at room temperature for 20min~40min to allow Ni impurities to precipitate; after solid-liquid separation, the solution is passed through a diatomaceous earth dynamic adsorption tower at a flow rate of 2BV / h~3BV / h to adsorb colloids and organic impurities; (3) The etching waste liquid after impurity removal is subjected to a gradient ammonia evaporation treatment combining atmospheric pressure ammonia evaporation and negative pressure ammonia evaporation to obtain a crude basic copper carbonate product; specifically, the treatment includes: atmospheric pressure ammonia evaporation at 80°C-95°C, evaporating to an ammonia concentration of <20%; negative pressure ammonia evaporation at 60°C-70°C and a vacuum degree of -0.08MPa~-0.05MPa to remove residual ammonia and obtain a crude basic copper carbonate product; washing with ethanol and water to remove impurity ions adsorbed on the surface; (4) The crude basic copper carbonate is dissolved in a urea solution to obtain a tetraammine copper carbonate solution; the temperature at which the crude basic copper carbonate is dissolved in the urea solution is 70°C to 90°C; (5) Secondary negative pressure ammonia evaporation treatment yields fine basic copper carbonate with a spherical honeycomb structure; (6) Coordinating the treatment of the basic copper carbonate product with graded calcination and water vapor activation to obtain highly active copper oxide; specifically, the step of placing the dried basic copper carbonate product into a microwave calcination furnace and performing gradient calcination and activation treatment in an air atmosphere; The gradient calcination activation treatment specifically includes: Heat to 200°C~300°C at the first heating rate and keep warm for 0.5h~1.5h; The temperature is raised to 400° C. to 500° C. at a second heating rate, 2 wt % to 4 wt % of water vapor is introduced into the microwave calcining furnace, and the temperature is maintained for 0.5 h to 1.5 h to obtain highly active copper oxide.

2. The method for recovering highly active copper oxide from alkaline etching waste liquid based on ammonia distillation according to claim 1, wherein: The pH value of the weakly alkaline etching waste liquid is 8.0-8.

2.

3. The method for recovering highly active copper oxide from alkaline etching waste liquid based on ammonia distillation according to claim 1, wherein: According to the molar ratio, urea: basic copper carbonate = 4~6:1; The concentration of the urea solution is 20wt%~30wt%.

4. The method for recovering highly active copper oxide from alkaline etching waste liquid based on ammonia distillation according to claim 1, wherein: The temperature of the secondary negative pressure ammonia evaporation is 85° C. to 95° C., and the vacuum degree is -0.03 MPa to -0.01 MPa.

5. The method for recovering highly active copper oxide from alkaline etching waste liquid based on ammonia distillation according to claim 1, wherein: The first heating rate is 4°C / min to 6°C / min; the second heating rate is 8°C / min to 12°C / min.

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