Method for recovering copper ions from a semiconductor copper process waste solution

Abstract

The application provides a method for recovering copper ions from semiconductor copper process waste liquid, comprising the following steps: S1, aerating the semiconductor copper process waste liquid for 0.5-1 h, then slowly adding modified starch, stirring and reacting, filtering, collecting filter residues to obtain a copper complex; the modified starch is prepared from mercaptoacetamide, 2-methoxy-6-vinylpyridine and starch; S2, washing the copper complex, then adding a sulfuric acid solution, stirring to dissolve the copper complex, obtaining a solution containing copper ions, and then using an electrolysis method to obtain elemental copper. The mercaptoacetamide and 2-methoxy-6-vinylpyridine in the modified starch jointly act, so that the complexing agent has high selectivity to copper ions, can effectively avoid the interference of impurities (such as nickel ions and iron ions), and thus the recovery purity of the copper ions is improved.

Description

TECHNICAL FIELD

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

[0002] The materials used in semiconductor copper process mainly include copper sulfate solution, various additives (leveling agent, mixed standard solution, inhibitor, leveling agent standard solution, accelerator standard solution) and copper electrode. 88% of the above raw material copper electrode is deposited on the chip surface, and 12% is collected as solid waste. 86% of the collected copper sulfate solution and various additives are treated as hazardous waste and transported for disposal. 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 contains not only copper ions but also other metal ions such as nickel, organic additives and acidic components, which requires efficient recovery of copper ions while avoiding the introduction of other metal ions to ensure the recovery yield of copper during the extraction process. SUMMARY

[0004] Therefore, the present application provides a method for recovering copper ions from semiconductor copper process waste liquid with high selectivity and high efficiency.

[0005] The technical scheme of the present application is as follows: The present application provides a method for recovering copper ions from semiconductor copper process waste liquid, comprising the following steps:

[0006] S1. The semiconductor copper process waste liquid is aerated for 0.5-1 h, then modified starch is slowly added, stirred and reacted, filtered, and the filter residue is collected to obtain a copper complex. The modified starch is prepared from mercaptoacetamide, 2-methoxy-6-vinylpyridine and starch.

[0007] S2. The copper complex is washed and added to a sulfuric acid solution, stirred to release the copper ions from the complex, and a solution containing copper ions is obtained. Then, elemental copper is obtained by electrolysis.

[0008] Mercaptoacetamide contains mercapto (-SH) and amide groups (-CONH2). Mercapto has strong coordination ability, especially for soft acids (such as Cu 2+ ) which has good complexing ability. 2-methoxy-6-vinylpyridine contains a pyridine ring and a vinyl group. 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 provides a large number of hydroxyl groups (-OH) as a matrix, making the complexing agent have good water solubility and dispersibility, and 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 easily accessible and bind to functional groups, while nickel ions have lower binding efficiency due to different coordination environments.

[0009] The thioacetamide and 2-methoxy-6-vinylpyridine in the modified starch work together to make the complexing agent highly selective for copper ions. Specifically, copper ions have high electronegativity and large ionic radius, which makes it easier for copper ions to form stable complexes with thiol and 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 lower affinity of nickel ions to 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 weak complexing ability, are less likely to form stable complexes with the complexing agent, thus remaining in the solution, achieving high selectivity separation of copper ions.

[0010] In addition, the methoxy and acetamide groups in the modified starch increase the hydrophilicity, which helps the modified starch to disperse and dissolve better in aqueous solution, enabling it to contact copper ions more effectively 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 effect, which ensures the structural integrity of the modified starch during the treatment of waste liquid, improves the durability of the modified starch in complex waste liquid environment, and ensures that it is not easily damaged by other organic additives or acidic components during the recovery process, thus improving its service life and efficiency.

[0011] The synergistic effect of various functional groups improves the selective recovery capacity of the modified starch for copper ions, which ensures that the modified starch can efficiently recover copper ions during the treatment of waste liquid while maintaining its structural stability and functionality.

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

[0013] The pH value in the range of 6-8 can provide a suitable environment for the modified starch, so that the functional groups (such as thiol and pyridine ring) can more effectively bind to copper ions to form stable complexes. Within this pH range, copper ions mainly exist in the form of Cu 2+ , which is conducive to the complexation reaction with the functional groups in the complexing agent. If the pH value is too low (the acidity is too strong), copper ions may exist in the form of Cu + or other forms, reducing the complexation efficiency; if the pH value is too high (the alkalinity is too strong), copper ions may form copper hydroxide precipitate, which is also not conducive to the complexation reaction.

[0014] In addition, within the pH value range of 6-8, nickel ions (Ni 2+The complexing ability of the complexing agent is relatively weak, which helps to improve the selective complexing 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 with the complexing agent for complexing, thereby affecting the separation effect of copper ions.

[0015] On the basis of the above technical scheme, preferably, in step S1, 0.1% to 1% of the volume of the waste liquid is added with hydrogen peroxide solution with a concentration of 30% during aeration.

[0016] Specifically, aeration is to convert monovalent copper in the waste liquid into divalent copper, so as to facilitate the formation of stable complexes with the complexing groups in the modified starch. The addition of hydrogen peroxide during aeration can oxidize organic impurities and reducing substances in the waste liquid, thereby reducing their interference with the complexing of copper ions by the modified starch.

[0017] On the basis of the above technical scheme, preferably, in step S1, the amount of the modified starch is 100 mg / L Cu 2+ The waste liquid is added with 0.4 to 0.6 g of the modified starch.

[0018] The amount of the modified starch is matched with the concentration of copper ions in the waste liquid to ensure that each copper ion can be complexed with sufficient modified starch. Excessive modified starch not only wastes materials, but also affects subsequent processing steps such as filtration and washing. Therefore, the amount of the modified starch in the present application should be controlled within a reasonable range to ensure that the complexing reaction is completely performed without excessive amount.

[0019] On the basis of the above technical scheme, preferably, in step S1, the reaction temperature is 20°C to 40°C, and the time is 0.5 to 1 h.

[0020] On the basis of the above technical scheme, preferably, the preparation method of the modified starch comprises the following contents:

[0021] S11, dispersing the starch in deionized water to form a starch slurry, then slowly adding mercaptoacetamide and stirring for 2 to 4 h; after the reaction is completed, the product is suction filtered, washed, and dried to obtain compound A;

[0022] S12, adding compound A into deionized water, adding 2-methoxy-6-vinylpyridine and ammonium persulfate, and stirring for 4 to 6 h; after the reaction is completed, the product is suction filtered, washed, and dried to obtain the modified starch.

[0023] On the basis of the above technical solutions, preferably, according to weight parts, the starch is 8-15 parts, the mercaptoacetamide is 10-15 parts, the 2-methoxy-6-vinylpyridine is 20-30 parts, and the 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; and the starch is one of sweet potato starch, corn starch, potato starch and wheat starch.

[0024] On the basis of the above technical solutions, preferably, the reaction conditions of step S11 are heated to 50-70 DEG C, and the reaction solution is adjusted to pH 7-8.

[0025] On the basis of the above technical solutions, preferably, the reaction conditions of step S12 are heated to 60-80 DEG C, and the reaction solution is adjusted to pH 4-6.

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

[0027] S21, titanium plating lead dioxide is used as an anode, and pure copper is used as a cathode;

[0028] S22, the solution containing copper ions in step S2 is added to an electrolytic tank, and electrolysis is carried out under the action of a direct current, so that the copper ions in the solution are electrolytically reduced into metallic copper and are recovered and treated; the electrolysis parameters are temperature 50-65 DEG C, tank voltage 2-3 V, and current density 240-260 A / m 2 .

[0029] The method for recovering copper ions from a semiconductor copper process waste liquid has the following beneficial effects relative to the prior art:

[0030] (1) The synergistic effect of the functional groups in the modified starch improves the high selective recovery capacity of copper ions, and the synergistic effect ensures that the modified starch can efficiently recover copper ions in the waste liquid treatment process while maintaining its structural stability and functionality.

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

[0032] (3) Hydrogen peroxide is added before complexation, which can oxidize organic impurities in the waste liquid through aeration, and at the same time, convert monovalent copper in the waste liquid into divalent copper, so as to facilitate the formation of stable complexes with the complexing groups in the modified starch and improve the recovery rate of copper. DETAILED DESCRIPTION

[0033] The technical solutions in the embodiments of the present application will be clearly and completely described below in combination with the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0034] 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 embodiment comprises the following steps:

[0037] S1, preparation of modified starch:

[0038] 12 g of sweet potato starch was dispersed in 120 g of deionized water to form a starch slurry, the pH of the starch slurry was adjusted to 8, then 13 g of mercaptoacetamide was slowly added, heated to 55℃, and stirred for 3 h; after the reaction was completed, the product was suction filtered, washed, and dried to obtain compound A;

[0039] 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, heated to 65℃, and stirred for 6 h; after the reaction was completed, the product was suction filtered, washed, and dried to obtain modified starch.

[0040] S2, 500 mL of copper process waste liquid was aerated for 1 h, then 0.6 g of modified starch was slowly added, and stirred at 30℃ for 1 h; the pH of the reaction solution was 5, after the reaction was completed, the filtrate was collected to obtain a copper complex.

[0041] S3, after the copper complex was washed, 5 times the mass of 1 mol / L sulfuric acid solution was added, and the copper ions were separated from the complex by stirring to obtain a solution containing copper ions.

[0042] S4, electrolysis: titanium-plated lead dioxide was used as the anode, and pure copper was used as the cathode, then the solution containing copper ions in step S3 was added to the electrolytic cell, and electrolysis was carried out under the action of direct current to reduce the copper ions in the solution to metallic copper and recover and process them; the electrolysis parameters were temperature 50℃, cell voltage 2V, and current density 240 A / m 2 .

[0043] Example 2

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

[0045] S1, preparing modified starch:

[0046] 12 g of sweet potato starch is dispersed in 120 g of deionized water to form a starch slurry, the pH of the starch slurry is adjusted to 8, then 13 g of mercaptoacetamide is slowly added, heated to 55 ℃, and stirred for 3 h; after the reaction is completed, the product is suction filtered, washed, and dried to obtain compound A;

[0047] Compound A is added to 75 g of deionized water, the pH is adjusted to 6, 20 g of 2-methoxy-6-vinylpyridine and 2 g of ammonium persulfate are added, heated to 65 ℃, and stirred for 6 h; after the reaction is completed, the product is suction filtered, washed, and dried to obtain modified starch.

[0048] S2, 500 mL of copper process waste liquid is aerated for 1 h, then 0.6 g of modified starch is slowly added, stirred at 30 ℃ for 1 h, and the pH value of the waste liquid is monitored periodically during the reaction, and if necessary, a buffer solution of acetic acid-sodium acetate is added to keep the pH value of the reaction liquid at 6. After the reaction is completed, filtration is performed, and the filter residue is collected to obtain a copper complex.

[0049] S3, after the copper complex is washed, 5 times the mass of 1 mol / L sulfuric acid solution is added, and the copper ions are separated from the complex by stirring to obtain a solution containing copper ions.

[0050] S4, electrolysis: titanium plating lead dioxide is used as the anode, and pure copper is used as the cathode, then the solution containing copper ions in step S3 is added to the electrolytic cell, and electrolysis is performed under the action of direct current to reduce the copper ions in the solution to metallic copper and recover the metallic copper; the electrolysis parameters are temperature 50 ℃, cell voltage 2 V, and current density 240 A / m 2 .

[0051] Example 3

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

[0053] S1, preparing modified starch:

[0054] 12 g of sweet potato starch is dispersed in 120 g of deionized water to form a starch slurry, the pH of the starch slurry is adjusted to 8, then 13 g of mercaptoacetamide is slowly added, heated to 55 ℃, and stirred for 3 h; after the reaction is completed, the product is suction filtered, washed, and dried 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 reaction was heated to 65°C and stirred for 6 h; after the reaction was completed, the product was suction filtered, washed, and dried to obtain the modified starch.

[0056] S2, 500 mL of copper process waste liquid was taken, 0.5% of the waste liquid volume was added to a 30% hydrogen peroxide solution, and aeration was carried out for 1 h; after the aeration was completed, 0.6 g of modified starch was slowly added, and the reaction was stirred at 30°C for 1 h; the pH value of the waste liquid was monitored periodically during the reaction, and if necessary, a buffer solution of acetic acid-sodium acetate buffer was added to keep the pH value of the reaction liquid at 6. After the reaction was completed, the copper complex was collected by filtration.

[0057] S3, after the copper complex was washed, 5 times the mass of 1 mol / L sulfuric acid solution was added, and the copper ions were separated from the complex by stirring to obtain a solution containing copper ions.

[0058] S4, electrolysis: titanium plating lead dioxide was used as the anode, and pure copper was used as the cathode, then the solution containing copper ions in step S3 was added to the electrolytic tank, and the electrolysis reaction was carried out under the action of direct current, the copper ions in the solution were reduced to metallic copper by electrolysis and were recovered; the electrolysis parameters were temperature 50°C, tank voltage 2V, and current density 240A / m 2 .

[0059] Example 4

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

[0061] S1, preparation of modified starch:

[0062] 8 g of corn starch was dispersed in 130 g of deionized water to form a starch slurry, the pH of the starch slurry was adjusted to 7, then 14 g of mercaptoacetamide was slowly added, and the reaction was heated to 50°C and stirred for 3.5 h; after the reaction was completed, the product was suction filtered, washed, and dried to obtain compound A;

[0063] Compound A was added to 60 g of deionized water, the pH was adjusted to 5.5, 20 g of 2-methoxy-6-vinylpyridine and 2.5 g of ammonium persulfate were added, and the reaction was heated to 60°C and stirred for 5.5 h; after the reaction was completed, the product was suction filtered, washed, and dried to obtain the modified starch.

[0064] S2, take 500 mL copper process waste liquid, add 0.1% of the volume of the waste liquid 30% concentration of hydrogen peroxide solution, aeration 40 min, after the end of aeration slowly add 0.4g modified starch, 35℃ stirring reaction 0.5h, reaction periodical monitoring of the pH value of the reaction solution, if necessary, add buffer acetic acid-sodium acetate buffer, so that the pH value of the reaction solution is 8. Reaction after filtration, collection of filter residue to obtain copper complex.

[0065] S3, after washing the copper complex, add 3 times the mass of 1.8 mol / L sulfuric acid solution, stirring to make copper ions from the complex free, to obtain a solution containing copper ions.

[0066] S4, electrolysis: with titanium plating lead dioxide as anode, with pure copper as cathode, then add the solution containing copper ions in step S3 into the electrolytic cell, under the action of direct current electrolysis, the copper ions in the solution are reduced to metallic copper by electrolysis and recycling; electrolysis parameters are temperature 50℃, tank voltage 2.5V, current density 240A / m 2 .

[0067] Example 5

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

[0069] S1, preparation of modified starch:

[0070] Disperse 15g potato starch in 90g deionized water to form starch slurry, adjust the pH of the starch slurry to 8, then slowly add 12g mercaptoacetamide, heat to 70℃, stirring reaction 2.5h; after the reaction, the product is suction filtered, washed and dried to obtain compound A;

[0071] Add compound A to 90g deionized water, adjust the pH to 4.5, add 30g 2-methoxy-6-vinylpyridine and 1.5g ammonium persulfate, heat to 80℃, stirring reaction 4.5h; after the reaction, the product is suction filtered, washed and dried to obtain modified starch.

[0072] S2, take 500 mL copper process waste liquid, add 1% of the volume of the waste liquid 30% concentration of hydrogen peroxide solution, aeration 0.5h, after the end of aeration slowly add 0.6g modified starch, 25℃ stirring reaction 1h, reaction periodical monitoring of the pH value of the reaction solution, if necessary, add buffer acetic acid-sodium acetate buffer, so that the pH value of the reaction solution is 6. Reaction after filtration, collection of filter residue to obtain copper complex.

[0073] S3, after washing the copper complex, add 5 times the mass of 1.2 mol / L sulfuric acid solution, stirring to make copper ions from the complex free, to obtain a solution containing copper ions.

[0074] S4, electrolysis: taking titanium-coated lead dioxide as an anode and pure copper as a cathode, then adding the solution containing copper ions in step S3 into an electrolytic cell, and performing electrolysis under the action of direct current, so that the copper ions in the solution are electrolytically reduced into metallic copper and recovered and treated; the electrolysis parameters are temperature 65℃, cell voltage 2.5V, and current density 260A / m 2 .

[0075] Example 6

[0076] The method for recovering copper ions from the semiconductor copper process waste liquid in the embodiment comprises the following steps:

[0077] S1, preparing modified starch:

[0078] 10g of wheat starch was dispersed in 110g of deionized water to form a starch slurry, the pH of the starch slurry was adjusted to 7.5, then 12.5g of mercaptoacetamide was slowly added, heated to 60℃, and stirred for 3h of reaction; after the reaction was completed, the product was suction filtered, washed, and dried to obtain compound A;

[0079] Compound A was added to 75g of deionized water, the pH was adjusted to 4.5, 26g of 2-methoxy-6-vinylpyridine and 2g of ammonium persulfate were added, heated to 70℃, and stirred for 5h of reaction; after the reaction was completed, the product was suction filtered, washed, and dried to obtain modified starch.

[0080] S2, 500mL of copper process waste liquid was taken, 0.3% of the volume of the waste liquid was added to a 30% hydrogen peroxide solution, aerated for 1h, then 0.55g of modified starch was slowly added, and stirred at 30℃ for 1h of reaction; the pH value of the reaction solution was monitored periodically during the reaction, and if necessary, a buffer solution of acetic acid-sodium acetate buffer was added to keep the pH value of the reaction solution at 7. The reaction was filtered after the reaction was completed, and the filter residue was collected to obtain a copper complex.

[0081] S3, after the copper complex was washed, 4 times the mass of a 1.5mol / L sulfuric acid solution was added, and the copper ions were separated from the complex by stirring to obtain a solution containing copper ions.

[0082] S4, electrolysis: taking titanium-coated lead dioxide as an anode and pure copper as a cathode, then adding the solution containing copper ions in step S3 into an electrolytic cell, and performing electrolysis under the action of direct current, so that the copper ions in the solution are electrolytically reduced into metallic copper and recovered and treated; the electrolysis parameters are temperature 65℃, cell voltage 2.5V, and current density 260A / m 2 .

[0083] Comparative Example 1

[0084] Comparative Example 1 and Example 1 are different in that the modified starch is compound A, i.e. mercaptoacetamide modified starch, and the rest of the steps are the same.

[0085] Comparative Example 2

[0086] Comparative Example 2 and Example 1 are different in that the amount of mercaptoacetamide is 18 g, which exceeds the limited range of the present application, and the rest of the steps are the same.

[0087] Comparative Example 3

[0088] Comparative Example 3 and Example 1 are different in that the modified starch is 2-methoxy-6-vinylpyridine modified starch, and the rest of the steps are the same. The preparation method of the modified starch is as follows: 12 g of starch is dispersed in 120 g of deionized water to form a starch slurry, the pH of the starch slurry is adjusted to 6, 20 g of 2-methoxy-6-vinylpyridine and 2 g of ammonium persulfate are added, and the mixture is heated to 65°C and stirred for 6 h. After the reaction is completed, the product is suction filtered, washed and dried to obtain the modified starch.

[0089] Comparative Example 4

[0090] Comparative Example 4 and Example 1 are different in that the amount of 2-methoxy-6-vinylpyridine is 35 g, which exceeds the limited range of the present application, and the rest of the steps are the same.

[0091] Comparative Example 5

[0092] Comparative Example 5 and Example 1 are different in that the amount of modified starch is 0.3 g, which exceeds the limited range of the present application, and the rest of the steps are the same.

[0093] The concentrations of copper ions and nickel ions in the waste liquid after the reaction in step S2 are determined, and the recovery rates of copper ions and nickel ions are calculated. 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 recovery rate of copper ions in Examples 1-6 of the present application can reach more than 99%, and the recovery rate of copper ions will decrease and the recovery rate of nickel ions will increase when the preparation of the modified starch lacks mercaptoacetamide, 2-methoxy-6-vinylpyridine or the original amount exceeds the limited range of the present application, which cannot achieve the technical effect of one-time high-selective recovery of copper ions. Therefore, it is proved that the modified starch and the recovery method of the present application have high selectivity for copper ions in the waste liquid.

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

[0099] The modified starch was recovered after decomplexation with sulfuric acid solution, and then reused 5 times to test its service life. The results are shown in the table below.

[0100] Table 2 Effect of repeated use of modified starch

[0101]

[0102] As shown in Table 2, after the modified starches of Examples 1 and 3 of the present application were reused 5 times, the recovery rate of copper ions could still reach more than 93%, and the recovery rate of nickel ions was less than 2%, which shows that the selectivity for copper ions is still relatively high, and also shows that the modified starch of the present application has a long service life.

[0103] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for recovering copper ions from semiconductor copper process wastewater, characterized by: The following steps are involved: S1, aerating semiconductor copper process wastewater 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 to a sulfuric acid solution, stirring to release copper ions from the complex to obtain a solution containing copper ions, and then electrolyzing to obtain elemental copper; The preparation method of the modified starch comprises the following contents: S11, dispersing starch in deionized water to form a starch slurry, then slowly adding mercaptoacetamide and stirring to react for 2-4 hours; after the reaction, filtering the product, washing, and drying to obtain compound A; S12, adding compound A from step S11 to deionized water, adding 2-methoxy-6-vinylpyridine and ammonium persulfate, and stirring to react for 4-6 hours; after the reaction is completed, filtering the product, washing, and drying to obtain modified starch; In parts by weight, the starch is 8 to 15 parts, the mercaptoacetamide is 10 to 15 parts, the 2-methoxy-6-vinylpyridine is 20 to 30 parts, and the 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.

2. The method for recovering copper ions from semiconductor copper process waste liquid according to claim 1, wherein: 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 according to claim 1, wherein: In step S1, a 30% hydrogen peroxide solution is added at a concentration of 0.1% to 1% of the waste liquid volume during aeration.

4. The method for recovering copper ions from semiconductor copper process waste liquid according to claim 1, wherein: In step S1, the amount of modified starch is 100 mg / L Cu 2+ Add 0.4~0.6g of modified starch to the waste liquid.

5. The method for recovering copper ions from semiconductor copper process waste liquid according to claim 1, wherein: 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 according to claim 1, wherein: The reaction conditions of step S11 are heating to 50-70° C. and adjusting the pH of the reaction solution to 7-8.

7. The method for recovering copper ions from semiconductor copper process waste liquid according to claim 1, wherein: The reaction conditions of step S12 are heating to 60-80° C. and adjusting the pH of the reaction solution to 4-6.

8. The method for recovering copper ions from semiconductor copper process waste liquid according to claim 1, wherein: The specific steps of electrolysis are: S21, titanium-plated lead dioxide as the anode and pure copper starting plate as the cathode; S22, adding the solution containing copper ions in step S2 to 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; the electrolytic parameters are a temperature of 50-65°C, a cell voltage of 2-3V, and a current density of 240-260A / m 2 .

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