Method for recovering copper ions from semiconductor copper process waste liquid

Abstract

The invention provides a method for recovering copper ions from semiconductor copper process waste liquid, which comprises the following steps: S1, aerating the semiconductor copper process waste liquid for 0.5-1 hour, then slowly adding modified starch, stirring to react, filtering, and collecting filter residues to obtain a copper complex; the modified starch is prepared from mercaptoacetamide, 2-methoxy-6-vinylpyridine and starch, and the modified starch is prepared from the mercaptoacetamide, 2-methoxy-6-vinylpyridine and the starch; and S2, the copper complex is washed and then added into a sulfuric acid solution, stirring is conducted to dissolve the copper complex, a solution containing copper ions is obtained, and then elementary substance copper is obtained through an electrolytic method. Mercaptoacetamide and 2-methoxy-6-vinylpyridine in the modified starch act together, so that the complexing agent has high selectivity on copper ions, interference of impurities (such as nickel ions and iron ions) can be effectively avoided, and the recovery purity of the copper ions is improved.

Description

Technical Field

[0001] The present invention relates to the field of copper process waste liquid recovery, and particularly to a method for recovering copper ions from semiconductor copper process waste liquid. Background Art

[0002] The main materials used in semiconductor copper process are copper sulfate solution, various additives (leveling agent, mixed standard solution, inhibitor, leveling agent standard solution, accelerator standard solution) and copper electrodes. 88% of the above-mentioned raw material copper electrodes are deposited on the chip surface, and 12% are collected as solid waste; 86% of the copper sulfate solution and various additives are collected and transported out for disposal as hazardous waste, and 10% of the copper sulfate solution attached to the chip surface is discharged with the cleaning wastewater and discharged into the copper-containing wastewater treatment system for treatment.

[0003] The copper-containing waste liquid not only contains copper ions, but also contains other metal ions such as nickel, organic additives and acidic components. This requires ensuring efficient recovery of copper ions during the extraction process, while avoiding the introduction of other metal ions and ensuring the recovery rate of the recovered copper. Summary of the Invention

[0004] In view of this, the present invention proposes a method with high selectivity for copper ions in semiconductor copper process waste liquid and can efficiently recover copper ions.

[0005] The technical solution of the present invention is realized as follows: The present invention provides a method for recovering copper ions from semiconductor copper process waste liquid, including the following steps:

[0006] S1, aerate the semiconductor copper process waste liquid for 0.5 - 1 h, then slowly add modified starch, stir and react, and then filter to collect the filter residue to obtain copper complex; the modified starch is prepared from mercaptoacetamide, 2-methoxy-6-vinylpyridine and starch;

[0007] S2, wash the copper complex and then add it to sulfuric acid solution, stir to free the copper ions from the complex to obtain a solution containing copper ions, and then obtain elemental copper by electrolysis.

[0008] Mercaptoacetamide contains a mercapto group (-SH) and an amide group (-CONH2), and the mercapto group has a strong coordination ability, especially for soft acids (such as Cu 2+ ) has a good complexing ability; 2-methoxy-6-vinylpyridine contains a pyridine ring and a vinyl group, and the nitrogen atom in the pyridine ring can provide a lone pair of electrons to form a coordination bond with metal ions, enhancing the complexing ability of the complexing agent. Starch serves as a matrix, providing a large number of hydroxyl groups (-OH), making the complexing agent have good water solubility and dispersibility, and at the same time introducing more functional groups through modification to enhance the complexing ability. In addition, the three-dimensional structure of the modified starch provides appropriate steric hindrance, making Cu 2+Ions are more likely to enter and bind to functional groups. Due to the different coordination environments, nickel ions have a lower binding efficiency.

[0009] In the modified starch of this application, mercaptoacetamide and 2-methoxy-6-vinylpyridine act together, enabling the complexing agent to have a high selectivity for copper ions. Specifically, copper ions have a relatively high electronegativity and a large ionic radius, which makes it easier for copper ions to form stable complexes with the sulfur atoms of the mercapto groups and the nitrogen atoms on the pyridine ring. In contrast, the electronegativity and ionic radius of nickel ions are different from those of copper ions, resulting in a lower affinity between them and the complexing agent. This high selectivity allows copper ions to be preferentially captured and precipitated by the modified starch, while nickel ions, due to their weaker complexing ability, are less likely to form stable complexes with the complexing agent and thus remain in the solution, achieving the high-selectivity separation of copper ions.

[0010] In addition, the methoxy and acetamide groups in the modified starch increase its hydrophilicity, which helps the modified starch to disperse and dissolve better in aqueous solutions, enabling it to more effectively contact copper ions and carry out complexation reactions, thus assisting the complexation process; the vinyl group enhances the stability and mechanical strength of the starch molecule through conjugation effects, which ensures the structural integrity of the modified starch during the waste liquid treatment process, improves the durability of the modified starch in complex waste liquid environments, and ensures that it is not easily damaged by other organic additives or acidic components during the recycling process, thereby increasing its service life and efficiency.

[0011] The synergistic effect of each functional group improves the selective recovery ability of the modified starch for copper ions. This synergistic effect ensures that the modified starch can efficiently recover copper ions during the waste liquid treatment process while maintaining its structural stability and functionality.

[0012] Based on the above technical solutions, preferably, during the reaction in step S1, the pH value of the reaction solution is regularly monitored, and a buffer solution is added if necessary to keep the pH value of the reaction solution at 6 - 8.

[0013] A pH value in the range of 6 - 8 can provide a suitable environment for the modified starch, enabling functional groups (such as mercapto groups and pyridine rings) to more effectively bind to copper ions and form stable complexes. In this pH range, copper ions mainly exist in the form of Cu 2+ , which is conducive to its complexation reaction with the functional groups in the complexing agent. If the pH value is too low (too acidic), copper ions may exist in the form of Cu + or other forms, reducing the complexation efficiency; if the pH value is too high (too alkaline), copper ions may form copper hydroxide precipitates, which is also not conducive to the progress of the complexation reaction.

[0014] In addition, in the pH range of 6 - 8, nickel ions (Ni 2+) has relatively weak complexing ability, which helps to improve the selective complexation of copper ions and reduce the interference of nickel ions. If the pH value is too low or too high, it may cause nickel ions or other impurity ions (such as iron, aluminum, etc.) to compete for complexation with the complexing agent, thus affecting the separation effect of copper ions.

[0015] Based on the above technical solutions, preferably, in step S1, a hydrogen peroxide solution with a concentration of 30% and a volume of 0.1% - 1% of the waste liquid volume is added during aeration.

[0016] Specifically, aeration is to convert monovalent copper in the waste liquid into divalent copper, which is convenient to form a stable complex with the complexing groups in the modified starch. Adding hydrogen peroxide during aeration can oxidize organic impurities and reducing substances in the waste liquid, reducing their interference with the complexation of copper ions by the modified starch.

[0017] Based on the above technical solutions, preferably, in step S1, the dosage of the modified starch is 100mg / LCu 2+ 0.4 - 0.6 g of modified starch is added to the waste liquid.

[0018] The dosage of the modified starch matches the concentration of copper ions in the waste liquid to ensure that each copper ion can be complexed by a sufficient amount of modified starch. Excessive modified starch not only wastes materials but also affects subsequent treatment steps such as filtration and washing. Therefore, the dosage of the modified starch in this application should be controlled within a reasonable range, which can not only ensure the complete progress of the complexation reaction but also not be excessive.

[0019] Based on the above technical solutions, preferably, in step S1, the reaction temperature is 20°C - 40°C and the time is 0.5 - 1 h.

[0020] Based on the above technical solutions, preferably, the preparation method of the modified starch includes the following content:

[0021] S11, disperse starch in deionized water to form a starch slurry, and then slowly add mercaptoacetamide and stir for 2 - 4 h; after the reaction, filter the product by suction, wash, and dry to obtain compound A;

[0022] S12, add compound A to deionized water, add 2 - methoxy - 6 - vinylpyridine and ammonium persulfate and stir for 4 - 6 h; after the reaction, filter the product by suction, wash, and dry to obtain the modified starch.

[0023] Based on the above technical solutions, preferably, by weight, the starch is 8-15 parts, mercaptoacetamide is 10-15 parts, 2-methoxy-6-vinylpyridine is 20-30 parts, ammonium persulfate is 1-3 parts; the deionized water in step S1 is 80-150 parts; the deionized water in step S2 is 60-90 parts; the starch is one of sweet potato starch, corn starch, potato starch, and wheat starch.

[0024] Based on the above technical solutions, preferably, the reaction conditions of step S11 are heating to 50-70 °C and adjusting the pH of the reaction solution to 7-8.

[0025] Based on the above technical solutions, preferably, the reaction conditions of step S12 are heating to 60-80 °C and adjusting the pH of the reaction solution to 4-6.

[0026] Based on the above technical solutions, preferably, the specific steps of the electrolysis method are as follows:

[0027] S21, using titanium-plated lead dioxide as the anode and a pure copper starting sheet as the cathode;

[0028] S22, adding the solution containing copper ions in step S2 into the electrolytic cell, and performing an electrolysis reaction under the action of a direct current. The copper ions in the solution are electrolytically reduced to metallic copper and recovered; the electrolysis parameters are a temperature of 50-65 °C, a cell voltage of 2-3 V, and a current density of 240-260 A / m 2 。

[0029] A method for recovering copper ions from waste liquid in a semiconductor copper manufacturing process of the present invention has the following beneficial effects compared with the prior art:

[0030] (1) The synergistic effect of each functional group in the modified starch of this application improves the high-selectivity recovery ability for copper ions. This synergistic effect ensures that the modified starch can efficiently recover copper ions during waste liquid treatment while maintaining its structural stability and functionality.

[0031] (2) Maintaining the pH of the reaction solution at 6-8 during the complexation reaction in this application helps to improve the selective complexation of copper ions and reduce the interference of nickel ions.

[0032] (3) Adding hydrogen peroxide before complexation and oxidizing the organic impurities in the waste liquid by aeration can convert the monovalent copper in the waste liquid into divalent copper, which is convenient for forming a stable complex with the complexing groups in the modified starch and improving the recovery rate of copper. Specific embodiments

[0033] Next, in combination with the embodiments of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0034] The method for recovering copper ions in the semiconductor copper process waste liquid is used in this aspect. The semiconductor copper process waste liquid used in the following examples and comparative examples contains 100 mg / L Cu ions and 100 mg / L Ni ions.

[0035] Example 1

[0036] The method for recovering copper ions from the semiconductor copper process waste liquid in this example includes the following steps:

[0037] S1. Prepare modified starch:

[0038] Disperse 12 g of sweet potato starch in 120 g of deionized water to form a starch slurry, adjust the pH of the starch slurry to 8, then slowly add 13 g of mercaptoacetamide, heat to 55 °C, and stir and react for 3 h; after the reaction is completed, filter the product by suction, wash, and dry to obtain compound A;

[0039] Add compound A to 75 g of deionized water, adjust the pH to 6, add 20 g of 2-methoxy-6-vinylpyridine and 2 g of ammonium persulfate, heat to 65 °C, and stir and react for 6 h; after the reaction is completed, filter the product by suction, wash, and dry to obtain modified starch.

[0040] S2. Take 500 mL of copper process waste liquid, aerate for 1 h, and then slowly add 0.6 g of modified starch after aeration. Stir and react at 30 °C for 1 h. The pH of the reaction solution is 5. After the reaction is completed, filter and collect the filter residue to obtain a copper complex.

[0041] S3. Wash the copper complex and add it to 5 times the mass of 1 mol / L sulfuric acid solution, stir to free the copper ions from the complex, and obtain a solution containing copper ions.

[0042] S4. Electrolysis: Use titanium-plated lead dioxide as the anode and a pure copper starter sheet as the cathode. Then add the solution containing copper ions in step S3 to the electrolytic cell and carry out an electrolysis reaction under the action of a direct current. The copper ions in the solution are electrolytically reduced to metallic copper and recovered; the electrolysis parameters are a temperature of 50 °C, a cell voltage of 2 V, and a current density of 240 A / m 2 .

[0043] Example 2

[0044] The method for recovering copper ions from the waste liquid of the semiconductor copper manufacturing process in this embodiment includes the following steps:

[0045] S1. Prepare modified starch:

[0046] Disperse 12 g of sweet potato starch in 120 g of deionized water to form a starch slurry, adjust the pH of the starch slurry to 8, then slowly add 13 g of mercaptoacetamide, heat to 55 °C, and stir and react for 3 h; after the reaction, filter the product by suction, wash, and dry to obtain compound A;

[0047] Add compound A to 75 g of deionized water, adjust the pH to 6, add 20 g of 2-methoxy-6-vinylpyridine and 2 g of ammonium persulfate, heat to 65 °C, and stir and react for 6 h; after the reaction, filter the product by suction, wash, and dry to obtain modified starch.

[0048] S2. Take 500 mL of the copper manufacturing process waste liquid, aerate for 1 h, after the aeration ends, slowly add 0.6 g of modified starch, stir and react at 30 °C for 1 h, regularly monitor the pH value of the waste liquid during the reaction, and add buffer acetic acid-sodium acetate buffer when necessary to keep the pH value of the reaction solution at 6. After the reaction, filter and collect the filter residue to obtain a copper complex.

[0049] S3. Wash the copper complex and add it to 5 times the mass of 1 mol / L sulfuric acid solution, stir to free the copper ions from the complex to obtain a solution containing copper ions.

[0050] S4. Electrolysis: Use titanium-plated lead dioxide as the anode and a pure copper starting sheet as the cathode, then add the solution containing copper ions in step S3 into the electrolytic cell, and carry out an electrolysis reaction under the action of a direct current. The copper ions in the solution are electrolytically reduced to metallic copper and recovered; the electrolysis parameters are a temperature of 50 °C, a cell voltage of 2 V, and a current density of 240 A / m 2 .

[0051] Example 3

[0052] The method for recovering copper ions from the waste liquid of the semiconductor copper manufacturing process in this embodiment includes the following steps:

[0053] S1. Prepare modified starch:

[0054] Disperse 12 g of sweet potato starch in 120 g of deionized water to form a starch slurry, adjust the pH of the starch slurry to 8, then slowly add 13 g of mercaptoacetamide, heat to 55 °C, and stir and react for 3 h; after the reaction, filter the product by suction, wash, and dry to obtain compound A;

[0055] Compound A was added to 75 g of deionized water, the pH was adjusted to 6, 20 g of 2-methoxy-6-vinylpyridine and 2 g of ammonium persulfate were added, and the mixture was heated to 65 °C and stirred for reaction for 6 h; after the reaction was completed, the product was filtered by suction, washed, and dried to obtain modified starch.

[0056] S2, Take 500 mL of copper process waste liquid, add a 30% hydrogen peroxide solution with a volume of 0.5% of the waste liquid volume, aerate for 1 h, and slowly add 0.6 g of modified starch after the aeration is completed. Stir and react at 30 °C for 1 h. During the reaction, the pH value of the waste liquid is monitored regularly, and a buffer solution, acetic acid-sodium acetate buffer solution, is added if necessary to keep the pH value of the reaction solution at 6. After the reaction is completed, filter and collect the filter residue to obtain copper complex.

[0057] S3, After washing the copper complex, add it to 5 times the mass of 1 mol / L sulfuric acid solution, stir to free the copper ions from the complex to obtain a solution containing copper ions.

[0058] S4, Electrolysis: Use titanium-plated lead dioxide as the anode and pure copper starting sheet as the cathode, then add the solution containing copper ions in step S3 into the electrolytic cell, and carry out electrolytic reaction under the action of direct current. The copper ions in the solution are electrolytically reduced to metallic copper and recovered; the electrolysis parameters are a temperature of 50 °C, a cell voltage of 2 V, and a current density of 240 A / m 2 。

[0059] Example 4

[0060] The method for recovering copper ions from the semiconductor copper process waste liquid in this example includes the following steps:

[0061] S1, Preparation of modified starch:

[0062] Disperse 8 g of corn starch in 130 g of deionized water to form a starch slurry, adjust the pH of the starch slurry to 7, then slowly add 14 g of mercaptoacetamide, heat to 50 °C, and stir and react for 3.5 h; after the reaction is completed, filter the product by suction, wash, and dry to obtain compound A;

[0063] Add compound A to 60 g of deionized water, adjust the pH to 5.5, add 20 g of 2-methoxy-6-vinylpyridine and 2.5 g of ammonium persulfate, heat to 60 °C, and stir and react for 5.5 h; after the reaction is completed, filter the product by suction, wash, and dry to obtain modified starch.

[0064] S2. Take 500 mL of copper process waste liquid, add 30% hydrogen peroxide solution with a volume of 0.1% of the waste liquid volume, aerate for 40 min. After the aeration ends, slowly add 0.4 g of modified starch, stir and react at 35 °C for 0.5 h. During the reaction, regularly monitor the pH value of the reaction solution, and add buffer solution acetic acid-sodium acetate buffer solution when necessary to keep the pH value of the reaction solution at 8. After the reaction ends, filter and collect the filter residue to obtain copper complex.

[0065] S3. Wash the copper complex and add it to 3 times the mass of 1.8 mol / L sulfuric acid solution, stir to free the copper ions from the complex to obtain a solution containing copper ions.

[0066] S4. Electrolysis: Use titanium-plated lead dioxide as the anode and pure copper starter sheet as the cathode. Then add the solution containing copper ions in step S3 into the electrolytic cell, and carry out electrolysis reaction under the action of direct current. The copper ions in the solution are electrolytically reduced to metallic copper and recovered; the electrolysis parameters are temperature 50 °C, cell voltage 2.5 V, current density 240 A / m 2 。

[0067] Example 5

[0068] The method for recovering copper ions from semiconductor copper process waste liquid in this example includes the following steps:

[0069] S1. Prepare modified starch:

[0070] Disperse 15 g of potato starch in 90 g of deionized water to form a starch slurry, adjust the pH of the starch slurry to 8, then slowly add 12 g of mercaptoacetamide, heat to 70 °C, and stir and react for 2.5 h; after the reaction ends, filter, wash, and dry the product to obtain compound A;

[0071] Add compound A to 90 g of deionized water, adjust the pH to 4.5, add 30 g of 2-methoxy-6-vinylpyridine and 1.5 g of ammonium persulfate, heat to 80 °C, and stir and react for 4.5 h; after the reaction ends, filter, wash, and dry the product to obtain modified starch.

[0072] S2. Take 500 mL of copper process waste liquid, add 30% hydrogen peroxide solution with a volume of 1% of the waste liquid volume, aerate for 0.5 h. After the aeration ends, slowly add 0.6 g of modified starch, stir and react at 25 °C for 1 h. During the reaction, regularly monitor the pH value of the reaction solution, and add buffer solution acetic acid-sodium acetate buffer solution when necessary to keep the pH value of the reaction solution at 6. After the reaction ends, filter and collect the filter residue to obtain copper complex.

[0073] S3. Wash the copper complex and add it to 5 times the mass of 1.2 mol / L sulfuric acid solution, stir to free the copper ions from the complex to obtain a solution containing copper ions.

[0074] S4, Electrolysis: Using titanium-plated lead dioxide as the anode and a pure copper starter sheet as the cathode, then adding the solution containing copper ions in step S3 into the electrolytic cell, and conducting an electrolysis reaction under the action of a direct current. The copper ions in the solution are electrolytically reduced to metallic copper and recovered; the electrolysis parameters are a temperature of 65 °C, a cell voltage of 2.5 V, and a current density of 260 A / m 2 .

[0075] Example 6

[0076] A method for recovering copper ions from the waste liquid of a semiconductor copper manufacturing process in this example includes the following steps:

[0077] S1, Preparation of modified starch:

[0078] Disperse 10 g of wheat starch in 110 g of deionized water to form a starch slurry, adjust the pH of the starch slurry to 7.5, then slowly add 12.5 g of mercaptoacetamide, heat to 60 °C, and stir and react for 3 h; after the reaction, filter the product by suction, wash, and dry to obtain compound A;

[0079] Add compound A to 75 g of deionized water, adjust the pH to 4.5, add 26 g of 2-methoxy-6-vinylpyridine and 2 g of ammonium persulfate, heat to 70 °C, and stir and react for 5 h; after the reaction, filter the product by suction, wash, and dry to obtain the modified starch.

[0080] S2, Take 500 mL of the copper manufacturing waste liquid, add a 30% hydrogen peroxide solution with a volume of 0.3% of the waste liquid volume, aerate for 1 h, and then slowly add 0.55 g of the modified starch after aeration. Stir and react at 30 °C for 1 h. Regularly monitor the pH value of the reaction solution during the reaction, and add a buffer solution, acetic acid-sodium acetate buffer solution if necessary, to keep the pH value of the reaction solution at 7. After the reaction, filter and collect the filter residue to obtain the copper complex.

[0081] S3, Wash the copper complex and add it to 4 times the mass of 1.5 mol / L sulfuric acid solution, stir to free the copper ions from the complex, and obtain a solution containing copper ions.

[0082] S4, Electrolysis: Using titanium-plated lead dioxide as the anode and a pure copper starter sheet as the cathode, then adding the solution containing copper ions in step S3 into the electrolytic cell, and conducting an electrolysis reaction under the action of a direct current. The copper ions in the solution are electrolytically reduced to metallic copper and recovered; the electrolysis parameters are a temperature of 60 °C, a cell voltage of 3 V, and a current density of 250 A / m 2 .

[0083] Comparative Example 1

[0084] Comparative Example 1 is different from Example 1 in that the modified starch is Compound A, namely mercaptoacetamide-modified starch, and the remaining steps are the same.

[0085] Comparative Example 2

[0086] The difference between Comparative Example 2 and Example 1 is that the amount of mercaptoacetamide is 18 g, exceeding the defined range of this application, and the remaining steps are the same.

[0087] Comparative Example 3

[0088] Comparative Example 3 is different from Example 1 in that the modified starch is 2-methoxy-6-vinylpyridine-modified starch, and the remaining steps are the same. The preparation method of the modified starch is as follows: Disperse 12 g of starch in 120 g of deionized water to form a starch slurry, adjust the pH of the starch slurry to 6, add 20 g of 2-methoxy-6-vinylpyridine and 2 g of ammonium persulfate, heat to 65 °C, and stir and react for 6 h; After the reaction is completed, filter the product by suction, wash, and dry to obtain the modified starch.

[0089] Comparative Example 4

[0090] The difference between Comparative Example 4 and Example 1 is that the amount of 2-methoxy-6-vinylpyridine is 35 g, exceeding the defined range of this application, and the remaining steps are the same.

[0091] Comparative Example 5

[0092] The difference between Comparative Example 5 and Example 1 is that the amount of the modified starch is 0.3 g, exceeding the defined range of this application, and the remaining steps are the same.

[0093] Measure the concentrations of copper ions and nickel ions in the waste liquid after the reaction in Step S2 is completed, and calculate the recovery rates of copper ions and nickel ions. The results are shown in the following table.

[0094] Table 1 Recovery Rates of Copper Ions and Nickel Ions

[0095]

[0096]

[0097] As can be seen from Table 1, the copper ions recovered in Examples 1 to 6 of this application can reach more than 99%. The lack of mercaptoacetamide, 2-methoxy-6-vinylpyridine during the preparation of the modified starch or the original amount exceeding the defined range of this application will all reduce the recovery rate of copper ions and increase the recovery rate of nickel ions, and it is impossible to achieve the technical effect of highly selectively recovering copper ions at one time. This proves that the modified starch and the recovery method of this application have high selectivity for copper ions in the waste liquid.

[0098] In the waste liquid from which copper ions have been recovered in Examples 1 to 6, adding modified starch can achieve the recovery of nickel ions, and the recovery efficiency can reach over 99%. The modified starch of the present application can achieve the technical effect of highly selectively recovering copper ions in the waste liquid, and at the same time can also achieve the purpose of recovering copper ions and nickel ions in stages, realizing the recovery of multiple metal elements.

[0099] After the modified starch is recovered by using a sulfuric acid solution to break the complex, the modified starch is reused 5 times, and its service life is detected. The results are shown in the following table.

[0100] Table 2 Reuse effect of modified starch

[0101]

[0102] As shown in Table 2, after the modified starch in Examples 1 and 3 of the present application is reused 5 times, the recovery rate of copper ions can still reach over 93%, and the recovery rate of nickel ions is less than 2%. This shows that high selectivity for copper ions is still maintained, and it also shows that the modified starch of the present application has a long service life.

[0103] The above is only the preferred embodiment of the present invention, and it is not used to limit the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for recovering copper ions from semiconductor copper process waste liquid, characterized in that: The following steps are involved: S1, aerating the semiconductor copper process waste liquid for 0.5 to 1 hour, then slowly adding modified starch, stirring for reaction, filtering, and collecting the filter residue to obtain a copper complex; the modified starch is prepared from mercaptoacetamide, 2-methoxy-6-vinylpyridine and starch; S2, washing the copper complex obtained in step S1 and adding it into a sulfuric acid solution, stirring to release copper ions from the complex, thereby obtaining a solution containing copper ions, and then obtaining elemental copper by electrolysis.

2. The method for recovering copper ions from semiconductor copper process waste liquid as claimed in claim 1, characterized in that: During the reaction in step S1, the pH value of the reaction solution is regularly monitored to maintain the pH value of the reaction solution at 6-8.

3. The method for recovering copper ions from semiconductor copper process waste liquid as claimed in claim 1, characterized in that: In step S1, 0.1% to 1% of the volume of the waste liquid and a 30% concentration of hydrogen peroxide solution are added during aeration.

4. The method for recovering copper ions from semiconductor copper process waste liquid as claimed in claim 1, characterized in that: In step S1, the dosage of the modified starch is 100 mg / L Cu 2+ Add 0.4-0.6 g of modified starch to the waste liquid.

5. The method for recovering copper ions from semiconductor copper process waste liquid as claimed in claim 1, characterized in that: In step S1, the reaction temperature is 20°C to 40°C, and the reaction time is 0.5 to 1 h.

6. The method for recovering copper ions from semiconductor copper process waste liquid as claimed in claim 1, characterized in that: The preparation method of the modified starch comprises the following contents: S11, dispersing starch in deionized water to form starch slurry, then slowly adding mercaptoacetamide, stirring and reacting for 2 to 4 hours; after the reaction is completed, filtering the product, washing, and drying to obtain compound A; S12, adding compound A in step S11 into deionized water, adding 2-methoxy-6-vinylpyridine and ammonium persulfate, and stirring to react for 4 to 6 hours; after the reaction is completed, filtering the product, washing, and drying to obtain modified starch.

7. The method for recovering copper ions from semiconductor copper process waste liquid as claimed in claim 6, characterized in that: In parts by weight, the starch is 8 to 15 parts, mercaptoacetamide is 10 to 15 parts, 2-methoxy-6-vinylpyridine is 20 to 30 parts, and ammonium persulfate is 1 to 3 parts; the deionized water in step S1 is 80 to 150 parts, and the deionized water in step S2 is 60 to 90 parts; the starch is one of sweet potato starch, corn starch, potato starch, and wheat starch.

8. The method for recovering copper ions from semiconductor copper process waste liquid as claimed in claim 6, characterized in that: The reaction conditions of step S11 are heating to 50-70° C. and adjusting the pH of the reaction solution to 7-8.

9. The method for recovering copper ions from semiconductor copper process waste liquid as claimed in claim 6, characterized in that: The reaction conditions of step S12 are heating to 60-80° C. and adjusting the pH of the reaction solution to 4-6.

10. The method for recovering copper ions from semiconductor copper process waste liquid as claimed in claim 1, characterized in that: The specific steps of electrolysis are: S21, titanium-plated lead dioxide as anode and pure copper starting plate as cathode; S22, adding the solution containing copper ions in step S2 into an electrolytic cell, and performing an electrolytic reaction under the action of a direct current, wherein the copper ions in the solution are electrolytically reduced to metallic copper and recovered for treatment; the electrolytic parameters are a temperature of 50 to 65°C, a cell voltage of 2 to 3V, and a current density of 240 to 260A / m 2 .

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