Method for recovering copper from post-etch rinse water

Abstract

The application discloses a method for recovering copper from rinsing wastewater after etching copper, which adopts a combination of extraction and back extraction to recover copper from the rinsing wastewater of a circuit board, and is more suitable for large-scale low-concentration rinsing wastewater compared with single-stage extraction or a simple chemical precipitation method, an electrolysis method, an ion exchange method and an adsorption method, can more fully and efficiently transfer copper ions from the large-scale low-concentration rinsing wastewater to an organic extractant, is more complete in copper extraction, has a high copper extraction yield, and can be recycled, so that the cost is reduced, and copper is effectively enriched after extraction and back extraction, and high-purity copper can be quickly obtained by combining the electrolysis method, and the whole process is efficient and environmentally friendly.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of etching copper recovery, in particular to a method for recovering copper from rinsing water after etching copper. BACKGROUND

[0002] In the process of manufacturing circuit boards, etching process is one of the key steps, which is used to define the circuit pattern. After etching, the circuit board must be rinsed to remove residual chemicals and metal ions, especially copper ions; this rinsing process will produce a large amount of rinsing wastewater containing copper ions; if these copper-containing rinsing wastewater is directly discharged into the environment without treatment, it will cause serious pollution to water and soil, and affect the ecological system. Although the concentration of copper ions in the rinsing wastewater is low, as an important non-ferrous metal, the recovery of copper not only helps to avoid resource waste, but also produces significant economic value; in addition, through recycling, the dependence on primary mineral resources can be reduced.

[0003] At present, the treatment methods for copper-containing rinsing wastewater mainly include chemical precipitation method, electrolysis method, ion exchange method and adsorption method, etc., but the use of the above methods alone will have certain limitations, for example, the chemical precipitation method mainly precipitates copper ions by adding chemical reagents, but this method may introduce new chemical substances, causing secondary pollution problems; the electrolysis method uses electrochemical principle to deposit copper ions from the solution, although this method has high efficiency, but the energy consumption is large and the cost is high, which is not suitable for low concentration wastewater treatment; for example, the ion exchange method selectively adsorbs copper ions using special resins or membrane materials, this method has good effect, but the resin regeneration process is complex and the cost is high; the adsorption method mainly uses activated carbon or other porous materials to adsorb copper ions, this method is simple to operate, but the adsorption capacity is limited, not suitable for large-scale low-concentration wastewater treatment.

[0004] Therefore, how to efficiently and environmentally recover copper from large-scale low-concentration rinsing wastewater has become an important topic that needs to be further studied. SUMMARY

[0005] To solve the above technical problems, the present application provides a high-efficiency and environmentally-friendly method for recovering copper from rinsing water after etching copper, comprising:

[0006] Pretreatment of rinsing wastewater: after rinsing the etched circuit board with clean water, collect the rinsing wastewater into a storage tank, filter and remove impurities to obtain pretreated rinsing wastewater;

[0007] Extraction: according to weight parts, 1-5 parts of pretreated rinsing wastewater is mixed with 1 part of the first organic extractant to stir and extract the copper in the pretreated rinsing wastewater, to obtain the first copper-rich organic phase and the first copper-lean raffinate, pH adjuster is added to the first copper-lean raffinate to adjust the pH of the first copper-lean raffinate to 2-3, then 1 part of the second organic extractant is added to every 5-9 parts of the first copper-lean raffinate to stir and extract again, to obtain the second copper-rich organic phase and the second copper-lean raffinate (the copper ion content is less than 20 mg / L), the second copper-lean raffinate is discharged to the comprehensive sewage station for treatment; wherein the first organic extractant and the second organic extractant have the same composition, which is obtained by mixing Lix 984H extractant, kerosene, di-(2-ethylhexyl) phosphate and bis(2,4,4-trimethylpentyl) phosphinic acid.

[0008] Stripping: according to weight parts, 1 part of sulfuric acid solution is added to every 5-9 parts of the second copper-rich organic phase to mix and strip to obtain the copper sulfate solution and the first copper-lean organic phase (the copper ion content is less than 20 mg / L), the copper sulfate solution is electrolyzed by the electrolytic cell to deposit and recover the cathode copper, wherein the anode of the electrolytic cell is selected from titanium-based plating lead dioxide, and the cathode is selected from copper mother sheet, the copper sulfate solution after electrolysis (the copper ion content is less than 10 g / L) is called copper-lean electrolyte, after adding sulfuric acid solution to the copper-lean electrolyte, the first copper-rich organic phase is mixed and stripped to obtain the copper sulfate solution and the second copper-lean organic phase, the copper sulfate solution is continuously electrolyzed to recover the cathode copper, and the first copper-lean organic phase and the second copper-lean organic phase are combined and then new first organic extractant is added to continue the extraction step to extract new pretreated rinsing wastewater.

[0009] Preferably, in the extraction process, the first organic extractant and the second organic extractant have the same composition, which is composed of the following components according to weight parts: 1-5 parts of Lix 984H extractant, 7-11 parts of kerosene, 1-3 parts of di-(2-ethylhexyl) phosphate, and 1-3 parts of bis(2,4,4-trimethylpentyl) phosphinic acid.

[0010] Preferably, in the extraction process, the first organic extractant and the second organic extractant have the same composition, which is composed of the following components according to weight parts: 3 parts of Lix 984H extractant, 9 parts of kerosene, 2 parts of di-(2-ethylhexyl) phosphate, and 2 parts of bis(2,4,4-trimethylpentyl) phosphinic acid.

[0011] Preferably, in the extraction process, the first organic extractant and the second organic extractant have the same composition, which is composed of the following components according to weight parts: 5 parts of Lix 984H extractant, 7 parts of kerosene, 1 part of di-(2-ethylhexyl) phosphate, and 1 part of bis(2,4,4-trimethylpentyl) phosphinic acid.

[0012] Preferably, during the extraction process, the first organic extractant and the second organic extractant have the same composition, and are composed of the following components in parts by weight: 1 part Lix 984H extractant, 11 parts kerosene, 3 parts di-(2-ethylhexyl) phosphate, and 3 parts bis(2,4,4-trimethylpentyl)phosphonic acid.

[0013] Preferably, citrate buffer is used as the pH adjuster during the extraction process. Using citrate buffer optimizes the extraction performance of the Lix 984H extractant and improves the extraction efficiency of copper ions.

[0014] Preferably, during the extraction process, the pretreated rinsing wastewater is mixed and stirred with the first organic extractant for 3 to 11 minutes, and then left to stand for 5 to 15 minutes.

[0015] Preferably, during the extraction process, the first raffinate is mixed and stirred with the second organic extractant for 3 to 11 minutes, and then left to stand for 5 to 15 minutes.

[0016] Preferably, the sulfuric acid solution concentration is 10–30 wt% during the back-extraction process.

[0017] Preferably, the sulfuric acid solution concentration is 20 wt% during the back-extraction process.

[0018] The beneficial effects are as follows: The first and second organic extractants of this application use Lix 984H extractant as the main copper extraction component. Lix 984H extractant can form copper complexes with copper ions. Kerosene is used to adjust the viscosity and density of the Lix 984H extractant. The addition of kerosene also prevents emulsification during extraction, ensuring clear stratification between the extractant and the aqueous phase, facilitating subsequent separation operations. Simultaneously, the addition of di-(2-ethylhexyl) phosphate and bis(2,4,4-trimethylpentyl)phosphonic acid, containing phosphoryl groups and hydrophobic long-chain alkyl groups respectively, allows them to coordinate with copper ions, synergistically forming a more stable copper-extractant complex with the Lix 984H extractant, thus improving the extraction efficiency of copper ions. Furthermore, this application adjusts the pH range to a suitable range according to the type of organic extractant, avoiding excessively low or high pH values ​​that could affect the extraction effect or lead to co-extraction of other metal ions, thereby improving the overall copper recovery rate and quality.

[0019] The copper complex obtained through the above extraction process can be back-extracted by a sulfuric acid solution, so that copper can be effectively recovered, and the extractant can also be regenerated and reused; the two-stage extraction system is adopted to maximize the recovery of copper ions, reduce the content of heavy metals in the wastewater, and reduce the impact on the environment; the first copper-poor organic phase and the second copper-poor organic phase are combined and then added with new first organic extractant to continue the extraction step, so that the organic extractant can be recycled, and the consumption of chemical reagents and waste emissions are reduced;

[0020] 1-5 parts of pretreated rinsing wastewater are mixed with 1 part of first organic extractant according to weight parts, so as to ensure the effective utilization rate of the extractant and the maximum extraction rate of copper ions; the pH of the first copper-poor raffinate is adjusted to 2-3 by adding a pH adjuster, and then secondary extraction is performed, so as to further improve the recovery rate of copper ions; sulfuric acid solution is used in the back-extraction process to effectively recover copper sulfate, and cathode copper is recovered by electrolysis, so that the whole process is efficient and stable, and high-quality copper products can be continuously produced;

[0021] In summary, compared with single-stage extraction or simple chemical precipitation, electrolysis, ion exchange and adsorption, the etched copper rinsing water copper recovery method provided by the present application can more fully and efficiently transfer copper ions from large-scale low-concentration rinsing wastewater to organic extractant, and the extraction of copper is more complete, and the extraction yield of copper is high; and the organic extractant can be recycled to reduce the cost, and copper is effectively enriched after extraction and back-extraction, and high-purity copper can be quickly obtained by combining electrolysis, and the whole process is efficient and environmentally friendly. DETAILED DESCRIPTION

[0022] The present application will be further described in detail below with reference to specific examples, so that those skilled in the art can more clearly understand the present application.

[0023] The following examples are used to illustrate the present application, but are not intended to limit the scope of the present application. Based on the specific examples in the present application, all other examples obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0024] In the embodiments of the present application, all raw material components are commercially available products well known to those skilled in the art unless otherwise specified; in the embodiments of the present application, the technical means used are conventional means well known to those skilled in the art unless otherwise specified.

[0025] Raw material sources:

[0026] The rinsing wastewater is collected from the circuit board rinsed with water after etching in Guangdong Meizhou Longyu Electronic Technology Co., Ltd.

[0027] Lix 984H extractant, purchased from Wuhan Jushun Chemical Co., Ltd.;

[0028] Kerosene, purchased from Wuhan Jiyie Sheng Chemical Co., Ltd.;

[0029] Di-(2-ethylhexyl) phosphate, purchased from Jiangsu Puleisi Biological Technology Co., Ltd.;

[0030] Bis(2,4,4-trimethylpentyl) phosphinic acid, purchased from Zhongshan Dixin Chemical Co., Ltd.;

[0031] Concentrated sulfuric acid, purchased from Guangdong Qiming Chemical Technology Co., Ltd.;

[0032] Titanium-based lead dioxide plating, purchased from Xi'an Airdi Environmental Protection Technology Co., Ltd.;

[0033] The remaining reagents and equipment are all conventional commercially available.

[0034] Example 1

[0035] The present embodiment provides a high-efficiency environmentally friendly copper etching post-rinsing water copper recovery method, comprising:

[0036] Rinsing wastewater pretreatment: after the etched circuit board is rinsed with clean water, the rinsing wastewater is collected into a storage tank, and activated carbon and polyvinylidene fluoride membrane are used in turn to filter impurities, to obtain pretreated rinsing wastewater;

[0037] Extraction: according to parts by weight, 1 part of pretreated rinsing wastewater is mixed with 1 part of first organic extractant at a speed of 500 r / min for 3 min, and the copper in the pretreated rinsing wastewater is extracted by standing for 5 min, to obtain a first copper-rich organic phase and a first copper-lean raffinate, a pH adjuster is added to the first copper-lean raffinate to adjust the pH of the first copper-lean raffinate to 2, the pH adjuster is selected to be citric acid buffer, then 1 part of second organic extractant is added to every 5 parts of the first copper-lean raffinate, mixed and stirred at a speed of 500 r / min for 3 min, and the second extraction is carried out by standing for 5 min, to obtain a second copper-rich organic phase and a second copper-lean raffinate (copper ion content 12.7 mg / L), the second copper-lean raffinate is discharged to the comprehensive wastewater treatment station for treatment; wherein the first organic extractant and the second organic extractant have the same composition, both of which are obtained by mixing 1 part of Lix 984H extractant, 11 parts of kerosene, 3 parts of di-(2-ethylhexyl) phosphate, and 3 parts of bis(2,4,4-trimethylpentyl) phosphinic acid;

[0038] Back extraction: according to weight parts, 1 part of 10wt% sulfuric acid solution is added to 5 parts of each second copper-rich organic phase to mix back extraction to obtain a copper sulfate solution and a first copper-poor organic phase (copper ion content is 13.4mg / L), the copper sulfate solution is electrolyzed to deposit and recover cathode copper through an electrolytic cell, wherein the anode of the electrolytic cell is selected to be a titanium-based plating lead dioxide, and the cathode is selected to be a copper mother sheet, the sulfuric acid copper solution (copper ion content is 5.5g / L) after electrolysis is called a copper-poor electrolyte, after adding a sulfuric acid solution to the copper-poor electrolyte, back extraction is carried out again with the first copper-rich organic phase to obtain a copper sulfate solution and a second copper-poor organic phase, the copper sulfate solution is continuously electrolyzed to recover cathode copper, and the first copper-poor organic phase and the second copper-poor organic phase are combined and then a new first organic extractant is added to continue the extraction step to extract new pretreated rinse wastewater.

[0039] Example 2

[0040] The embodiment provides a high-efficiency and environmentally-friendly copper recovery method for etched copper post-rinse water, comprising:

[0041] Rinse wastewater pretreatment: after the etched circuit board is rinsed with clean water, the rinse wastewater is collected into a storage tank, and activated carbon and a polyvinylidene fluoride membrane are used in sequence to filter and remove impurities to obtain pretreated rinse wastewater;

[0042] Extraction: according to weight parts, 3 parts of pretreated rinse wastewater are mixed with 1 part of a first organic extractant at a speed of 1000r / min for 7min, and then left to stand for 10min to extract copper from the pretreated rinse wastewater, to obtain a first copper-rich organic phase and a first copper-poor raffinate, a pH adjuster is added to the first copper-poor raffinate to adjust the pH of the first copper-poor raffinate to 3, the pH adjuster is selected to be a citric acid buffer, then 1 part of a second organic extractant is added to each 7 parts of the first copper-poor raffinate to mix at a speed of 1000r / min for 7min, and then left to stand for 10min to perform secondary extraction, to obtain a second copper-rich organic phase and a second copper-poor raffinate (copper ion content is less than 10.2mg / L), and the second copper-poor raffinate is discharged to a comprehensive sewage station for treatment; wherein the first organic extractant and the second organic extractant have the same composition, and are obtained by mixing 3 parts of Lix 984H extractant, 9 parts of kerosene, 2 parts of di-(2-ethylhexyl) phosphate, and 2 parts of bis(2,4,4-trimethylpentyl) phosphinic acid;

[0043] Back extraction: according to weight parts, 1 part of 20wt% sulfuric acid solution is added to each 7 parts of the second copper-rich organic phase to mix back extraction to obtain a copper sulfate solution and a first copper-lean organic phase (copper ion content is 11.8 mg / L), the copper sulfate solution is electrolyzed to deposit and recover cathode copper through an electrolytic cell, wherein the anode of the electrolytic cell is selected to be a titanium-based plating lead dioxide, and the cathode is selected to be a copper mother sheet, the copper sulfate solution after electrolysis (copper ion content is 5.1 g / L) is called a copper-lean electrolyte, after adding a sulfuric acid solution to the copper-lean electrolyte, back extraction is carried out again with the first copper-rich organic phase to obtain a copper sulfate solution and a second copper-lean organic phase, the copper sulfate solution is continuously electrolyzed to recover cathode copper, and the first copper-lean organic phase and the second copper-lean organic phase are combined and then a new first organic extractant is added to continue the extraction step to extract new pretreated rinse wastewater.

[0044] Example 3

[0045] The embodiment provides a high-efficiency and environmentally-friendly copper recovery method for etched copper post-rinse water, comprising:

[0046] Rinse wastewater pretreatment: after the etched circuit board is rinsed with clean water, the rinse wastewater is collected into a storage tank, and impurities are removed by active carbon and polyvinylidene fluoride membrane filtration in sequence to obtain pretreated rinse wastewater;

[0047] Extraction: according to weight parts, 5 parts of pretreated rinse wastewater are mixed with 1 part of a first organic extractant at a speed of 1500 r / min for 11 min, and then standing for 15 min to extract copper in the pretreated rinse wastewater, to obtain a first copper-rich organic phase and a first copper-lean raffinate, a pH adjuster is added to the first copper-lean raffinate to adjust the pH of the first copper-lean raffinate to 2, the pH adjuster is selected to be a citric acid buffer, then 1 part of a second organic extractant is added to each 9 parts of the first copper-lean raffinate to mix at a speed of 1500 r / min for 11 min, and then standing for 15 min to carry out secondary extraction, to obtain a second copper-rich organic phase and a second copper-lean raffinate (copper ion content is 9.8 mg / L), and the second copper-lean raffinate is discharged to a comprehensive sewage station for treatment; wherein the first organic extractant and the second organic extractant have the same composition, and are obtained by mixing 5 parts of Lix 984H extractant, 7 parts of kerosene, 1 part of di-(2-ethylhexyl) phosphate, and 1 part of bis(2,4,4-trimethylpentyl) phosphinic acid;

[0048] Stripping: according to weight parts, 1 part of 30wt% sulfuric acid solution is added to each 9 parts of the second copper-rich organic phase to mix and strip to obtain a copper sulfate solution and a first copper-lean organic phase (copper ion content less than 11.1 mg / L), the copper sulfate solution is electrolyzed by an electrolytic cell to deposit and recover cathode copper, wherein the anode of the electrolytic cell is selected to be a titanium-based plating lead dioxide, and the cathode is selected to be a copper mother sheet, the copper sulfate solution after electrolysis (copper ion content is 4.8 g / L) is called a copper-lean electrolyte, after adding a sulfuric acid solution to the copper-lean electrolyte, the copper sulfate solution is mixed and stripped with the first copper-rich organic phase to obtain a copper sulfate solution and a second copper-lean organic phase, the copper sulfate solution is continuously electrolyzed to recover cathode copper, and the first copper-lean organic phase and the second copper-lean organic phase are combined and then a new first organic extractant is added to continue the extraction step to extract new pretreated rinse wastewater.

[0049] Comparative Example 1

[0050] The present comparative example provides an efficient and environmentally friendly copper recovery method for etching copper post-rinse water, comprising:

[0051] Rinse wastewater pretreatment: after the etched circuit board is rinsed with clean water, the rinse wastewater is collected into a storage tank, and activated carbon and polyvinylidene fluoride membrane are used in sequence to filter and remove impurities to obtain pretreated rinse wastewater;

[0052] Extraction: according to weight parts, 5 parts of pretreated rinse wastewater are mixed with 1 part of a first organic extractant at a speed of 1500 r / min for 11 min, and then left to stand for 15 min to extract copper from the pretreated rinse wastewater, to obtain a first copper-rich organic phase and a first copper-lean raffinate, a pH adjuster is added to the first copper-lean raffinate to adjust the pH of the first copper-lean raffinate to 2, the pH adjuster is selected to be a citric acid buffer, then 1 part of a second organic extractant is added to each 9 parts of the first copper-lean raffinate to mix and stir at a speed of 1500 r / min for 11 min, and then left to stand for 15 min for secondary extraction, to obtain a second copper-rich organic phase and a second copper-lean raffinate (copper ion content is 19.8 mg / L), the second copper-lean raffinate is discharged to a comprehensive sewage station for treatment; wherein the first organic extractant and the second organic extractant have the same composition, and are both obtained by mixing 5 parts of Lix 984H extractant and 7 parts of kerosene;

[0053] Stripping: according to weight parts, 1 part of 5wt% sulfuric acid solution is added to each 11 parts of the second copper-rich organic phase to mix and strip to obtain a copper sulfate solution and a first copper-lean organic phase (copper ion content is 18.7 mg / L), the copper sulfate solution is electrolyzed by an electrolytic cell to deposit and recover cathode copper, wherein the anode of the electrolytic cell is selected to be a titanium-based plating lead dioxide, and the cathode is selected to be a copper mother sheet, the copper sulfate solution after electrolysis (copper ion content is 4.9 g / L) is called a copper-lean electrolyte, after adding a sulfuric acid solution to the copper-lean electrolyte, the copper-lean electrolyte is mixed and stripped with the first copper-rich organic phase to obtain a copper sulfate solution and a second copper-lean organic phase, the copper sulfate solution is continuously electrolyzed to recover cathode copper, and the first copper-lean organic phase and the second copper-lean organic phase are combined and then a new first organic extractant is added to continue the extraction step to extract new pretreated rinse wastewater.

[0054] Comparative Example 2

[0055] The present comparative example provides a high-efficiency and environmentally friendly copper recovery method for etching copper post-rinse water, comprising:

[0056] Rinse wastewater pretreatment: after the etched circuit board is rinsed with clean water, the rinse wastewater is collected into a storage tank, and activated carbon and a polyvinylidene fluoride membrane are used in sequence to filter and remove impurities to obtain pretreated rinse wastewater;

[0057] Extraction: according to weight parts, 5 parts of pretreated rinse wastewater are mixed with 1 part of a first organic extractant at a speed of 1500 r / min for 11 min, and then left to stand for 15 min to extract copper from the pretreated rinse wastewater, to obtain a first copper-rich organic phase and a first copper-lean raffinate, a pH adjuster is added to the first copper-lean raffinate to adjust the pH of the first copper-lean raffinate to 1, the pH adjuster is selected to be a 70wt% sulfuric acid solution, then 1 part of a second organic extractant is added to each 9 parts of the first copper-lean raffinate to mix and stir at a speed of 1500 r / min for 11 min, and then left to stand for 15 min for secondary extraction, to obtain a second copper-rich organic phase and a second copper-lean raffinate (copper ion content is 17.6 mg / L), the second copper-lean raffinate is discharged to a comprehensive sewage station for treatment; wherein the first organic extractant and the second organic extractant have the same composition, and are both obtained by mixing 5 parts of Lix 984H extractant and 7 parts of kerosene;

[0058] Back extraction: according to weight parts, 1 part of 70wt% sulfuric acid solution is added to each 9 parts of the second copper-rich organic phase to mix back extraction to obtain a copper sulfate solution and a first copper-lean organic phase (the copper ion content is less than 15.7mg / L), the copper sulfate solution is electrolyzed and deposited by an electrolytic cell to recover cathode copper, wherein the anode of the electrolytic cell is selected from a titanium-based plating lead dioxide, and the cathode is selected from a copper mother sheet, the copper sulfate solution after electrolysis (the copper ion content is 4.8g / L) is called a copper-lean electrolyte, after adding a sulfuric acid solution to the copper-lean electrolyte, the copper-lean electrolyte is mixed back extraction with the first copper-rich organic phase to obtain a copper sulfate solution and a second copper-lean organic phase, the copper sulfate solution is continuously electrolyzed to recover cathode copper, and the first copper-lean organic phase and the second copper-lean organic phase are combined and then a new first organic extractant is added to continue the extraction step to extract new pretreated rinsing wastewater.

[0059] As can be seen from Examples 1-3, in the extraction process, the ratio between the pretreated rinsing wastewater and the first organic extractant, the extraction speed in the extraction process, the stirring time, the standing time, and the pH value, the ratio between the first copper-lean raffinate and the second organic extractant, and the proportion of the first organic extractant and the second organic extractant all have important influences on the extraction yield of copper, and in the back extraction process, the ratio between the second copper-rich organic phase and the sulfuric acid solution and the concentration of the sulfuric acid solution also affect the back extraction yield of copper. As can be seen from the three examples, the extraction yield of copper in Example 3 is the highest, and the back extraction yield of copper is also the highest. As can be seen from the comparison between Comparative Example 1 and Example 3, when the composition of the first organic extractant and the second organic extractant is changed in the extraction process of Comparative Example 1, the extraction yield of copper is reduced, and when the ratio between the second copper-rich organic phase and the sulfuric acid solution is changed and the concentration of the sulfuric acid solution is reduced in the back extraction process, the back extraction yield of copper is also reduced. As can be seen from the comparison between Comparative Example 2 and Example 3, when 70wt% sulfuric acid solution is used to replace citric acid buffer as a pH regulator in the extraction process of Comparative Example 2, and the pH of the first copper-lean raffinate is adjusted to 1, the extraction yield of copper is reduced, and when the concentration of the back extraction agent sulfuric acid solution is increased in the back extraction process, the back extraction yield of copper is also reduced.

[0060] The above merely illustrates the embodiments of the present application, and is not intended to limit the present application. The present application can have various modifications and changes for those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the scope of claims of the present application.

Claims

1. A method of recovering copper from post-etch rinse water, the method comprising: providing a source of copper ions; and adding the source of copper ions to the post-etch rinse water. The method comprises the following steps: Rinse wastewater pretreatment: after the etched circuit board is rinsed with clean water, the rinse wastewater is collected into a storage tank, impurity is removed by filtration, and pretreated rinse wastewater is obtained; Extraction: according to weight fraction, 1-5 parts of the pretreated rinse wastewater is mixed with 1 part of a first organic extractant to extract copper in the pretreated rinse wastewater by stirring and standing, to obtain a first copper-rich organic phase and a first copper-lean raffinate, a pH adjuster is added to the first copper-lean raffinate to adjust the pH of the first copper-lean raffinate to 2-3, then 1 part of a second organic extractant is added to every 5-9 parts of the first copper-lean raffinate to carry out secondary extraction by stirring and standing, to obtain a second copper-rich organic phase and a second copper-lean raffinate, the copper ion content of the second copper-lean raffinate is less than 20 mg / L, and the second copper-lean raffinate is discharged to a comprehensive wastewater treatment station; wherein, in the extraction process, the first organic extractant and the second organic extractant have the same composition, and are composed of the following components by weight fraction: 1-5 parts of Lix 984H extractant, 7-11 parts of kerosene, 1-3 parts of di-(2-ethylhexyl) phosphate, and 1-3 parts of bis(2,4,4-trimethylpentyl) phosphinic acid; Stripping: according to weight fraction, 1 part of a sulfuric acid solution is added to every 5-9 parts of the second copper-rich organic phase to obtain a copper sulfate solution and a first copper-lean organic phase by stripping, the copper ion content of the first copper-lean organic phase is less than 20 mg / L, and the copper sulfate solution is electrolyzed in an electrolytic cell to recover cathode copper, wherein the anode of the electrolytic cell is selected from a titanium-based lead dioxide plating, and the cathode is selected from a copper mother sheet, the copper sulfate solution after electrolysis is called a copper-lean electrolyte, the copper ion content of the copper-lean electrolyte is less than 10 g / L, a sulfuric acid solution is added to the copper-lean electrolyte, and then the first copper-rich organic phase is mixed with the copper-lean electrolyte to obtain a copper sulfate solution and a second copper-lean organic phase, the copper sulfate solution is continuously electrolyzed to recover cathode copper, and the first copper-lean organic phase and the second copper-lean organic phase are combined and then new first organic extractant is added to continue the extraction step to extract new pretreated rinse wastewater; In the extraction process, the pH adjuster is selected from a citric acid buffer, and the pH value range needs to be adjusted to an appropriate range according to the type of organic extractant to avoid affecting the extraction effect or causing co-extraction of other metal ions, and the use of citric acid buffer can optimize the extraction performance of Lix 984H extractant and improve the extraction rate of copper ions to a certain extent; In the extraction process, the pretreated rinse wastewater is mixed with the first organic extractant by stirring for 3-11 min and standing for 5-15 min; In the extraction process, the first copper-lean raffinate is mixed with the second organic extractant by stirring for 3-11 min and standing for 5-15 min; In the stripping process, the concentration of the 1 part of sulfuric acid solution is 10-30 wt%.

2. The method of claim 1, wherein the post-etch copper rinse water copper recovery process is characterized by, In the extraction process, the first organic extractant and the second organic extractant are composed of the same components and consist of, by weight fraction: 3 parts Lix 984H extractant, 9 parts kerosene, 2 parts di-(2-ethylhexyl)phosphoric acid ester, 2 parts bis(2,4,4-trimethylpentyl) phosphinic acid mixture.

3. The method of claim 1, wherein the post-etch copper rinse water copper recovery process is characterized by, In the extraction process, the first organic extractant and the second organic extractant are composed of the same components and consist of, by weight fraction: 5 parts Lix 984H extractant, 7 parts kerosene, 1 part di-(2-ethylhexyl)phosphoric acid ester, 1 part bis(2,4,4-trimethylpentyl) phosphinic acid mixture.

4. The method of claim 1, wherein the post-etch copper rinse water copper recovery process is characterized by, In the extraction process, the first organic extractant and the second organic extractant are composed of the same components and consist of, by weight fraction: 1 part Lix 984H extractant, 11 parts kerosene, 3 parts di-(2-ethylhexyl)phosphoric acid ester, 3 parts bis(2,4,4-trimethylpentyl) phosphinic acid mixture.