Extraction process of 7N ultrahigh-purity copper

Abstract

The invention discloses a 7N ultra-high pure copper extraction process, and belongs to the technical field of 7N ultra-high pure copper extraction, and the 7N ultra-high pure copper extraction process comprises the following steps: S1, preparation; s2, constructing a structure for electrolytic extraction of 7N ultra-high pure copper; s3, pure copper is extracted through electrolysis, and meanwhile anode mud is conveyed and collected; s4, stripping the copper sheet, washing, drying and detecting, if the purity of 7N is not reached, taking the copper sheet as an anode material, and repeating the steps until the purity of 7N is reached; according to the invention, automatic cleaning of anode mud can be realized, frequent interruption of reaction is avoided, and the extraction efficiency of 7N ultra-high purity copper is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of 7N ultra-high purity copper extraction, and particularly relates to a 7N ultra-high purity copper extraction process. Background Art

[0002] 7N ultra-high purity copper refers to copper materials with a purity of up to 99.99999%, which have excellent electrical conductivity, thermal conductivity, ductility and processing performance, and are widely used in the fields of electronics, semiconductors, aerospace and precision instrument manufacturing.

[0003] The current 7N ultra-high purity copper extraction process is generally the electrolytic refining method, including an electrolytic cell with a copper sulfate solution as the electrolyte and a diaphragm, a 4N copper anode material and a pure copper cathode material. The 4N copper anode material and the pure copper cathode material are respectively placed on both sides of the diaphragm in the electrolytic cell. The 4N copper anode material is connected to the positive pole of the power supply, and the pure copper cathode material is connected to the negative pole of the power supply to form a complete electrolytic circuit. During extraction, the power supply is started. Copper atoms of the 4N copper anode material lose electrons under the action of the electric field and turn into copper ions and enter the electrolyte. The copper ions in the electrolyte flow towards the pure copper cathode material, gain electrons on the surface of the pure copper cathode material and are reduced to copper atoms and deposited. When the copper deposited on the pure copper cathode material reaches the preset thickness, the power supply is turned off, the pure copper cathode material is taken out, the copper sheet is peeled off for treatment and detection. If the 7N purity is not reached, the copper sheet is used as the anode material, and the above steps are repeated until the 7N purity is reached.

[0004] The existing technology has the following problems: During the process that copper atoms of the 4N copper anode material lose electrons under the action of the electric field and turn into copper ions and enter the electrolyte, impurities such as gold and silver that are less active than copper will precipitate at the bottom of the electrolytic cell in the form of anode mud. When the anode mud accumulates to a certain extent, it will cover the surface of the 4N copper anode material, hinder the normal dissolution of the 4N copper anode material, resulting in a decrease in the electrolysis efficiency, and may even cause problems such as short circuits. Therefore, it is necessary to frequently interrupt the reaction to clean the anode mud, which affects the extraction efficiency of 7N ultra-high purity copper.

[0005] In view of this, a 7N ultra-high purity copper extraction process is designed to solve the above problems. Summary of the Invention

[0006] To solve the problems raised in the above background art, the present invention provides a 7N ultra-high purity copper extraction process, which has the characteristic of improving the extraction efficiency of 7N ultra-high purity copper.

[0007] To achieve the above object, the present invention provides the following technical solution: A 7N ultra-high purity copper extraction process, comprising the following steps: S1: Prepare an electrolytic cell, an anodic slime upward delivery membrane, a cation exchange membrane, an anodic slime collection mechanism, a crude copper anode material, a pure copper cathode material, and a copper sulfate electrolyte circulation mechanism. Among them, the anodic slime upward delivery membrane includes a composite support layer, a functional gas-producing layer, and a diversion layer; S2: Install the anodic slime upward delivery membrane and the cation exchange membrane on both sides inside the electrolytic cell with a gap in the middle. The support layer of the anodic slime upward delivery membrane faces the cation exchange membrane, and there is a gap between the bottom end of the anodic slime upward delivery membrane and the bottom end of the electrolytic cell. Install the anodic slime collection mechanism above the anodic slime upward delivery membrane, install the crude copper anode material on the side of the electrolytic cell interior close to the diversion layer of the anodic slime upward delivery membrane, install the pure copper cathode material on the side of the electrolytic cell interior close to the cation exchange membrane, install the copper sulfate electrolyte circulation mechanism on the electrolytic cell, circulate and transport the copper sulfate electrolyte into the electrolytic cell interior, connect the crude copper anode material to the positive pole of the power supply, connect the pure copper cathode material to the negative pole of the power supply, and construct a structure for electrolytic extraction of 7N ultra-high purity copper; S3: Start the power supply. Copper atoms in the crude copper anode material lose electrons under the action of the electric field and turn into copper ions to enter the electrolyte. As the circulating electrolyte flows towards the pure copper cathode material, they gain electrons on the surface of the pure copper cathode material and are reduced to copper atoms and deposited. The inactive impurities including gold and silver in the crude copper anode material become anodic slime and deposit. The deposited anodic slime enters the gap between the anodic slime upward delivery membrane and the electrolytic cell under the driving action of the circulating electrolyte. Bubbles are generated in the functional gas-producing layer of the anodic slime upward delivery membrane. During the upward rise of the bubbles, an upward thrust is generated to push the anodic slime entering the anodic slime upward delivery membrane to move upward and be collected by the anodic slime collection mechanism; S4: When the copper deposited on the pure copper cathode material reaches the preset thickness, turn off the power supply, take out the pure copper cathode material, strip the copper sheet, wash, dry, and detect. If the 7N purity is not reached, use the copper sheet as the anode material and repeat the above steps until the 7N purity is reached.

[0008] Further, in the step S1, the support layer is a PTFE film, the functional gas-producing layer is a ruthenium-doped titanium dioxide ceramic matrix loaded with nano-platinum particles, and the diversion layer is a PAN fiber felt.

[0009] Further, in the step S1, the preparation of the anodic slime upward delivery membrane includes the following steps: Use the extrusion molding process to make a PTFE resin into a film with uniform thickness, and then perform a stretching treatment to improve its strength and porosity as the support layer; Prepare a ruthenium-doped titanium dioxide ceramic matrix through the sol-gel process, and then load nano-platinum particles into the pores of the ceramic matrix through the impregnation method as the functional gas-producing layer; Composite the prepared functional gas-producing layer with the support layer through the hot pressing process; Prepare a PAN fiber felt through the electrospinning process as the diversion layer; The current collector layer is bonded to the composite support layer and the functional gas generation layer through an adhesive to form a multi-layer composite separator, namely, the anode sludge upward feeding film.

[0010] Further, in the step S1, the anode sludge collection mechanism includes a suction pump, a collection box, a filter screen, and a collection pipe. One end of the collection box is connected to the suction pump, the inside of the collection box is connected to the filter screen, the other end of the collection box is connected to the collection pipe, and the collection pipe is located above the anode sludge upward feeding film; Start the suction pump to create negative pressure in the collection box and the collection pipe; The anode sludge on the anode sludge upward feeding film is sucked into the collection box through the collection pipe.

[0011] Further, in the step S1, the copper sulfate electrolyte circulation mechanism includes a copper sulfate electrolyte tank, a delivery pump, and a delivery pipeline. Both ends of the copper sulfate electrolyte tank are connected to the delivery pipeline. One end of the delivery pipeline is connected to one side of the electrolytic cell, the other end of the delivery pipeline is connected to the delivery pump, and the other end of the delivery pump is connected to the delivery pipeline, and the other end of the delivery pipeline is connected to the other side of the electrolytic cell; The copper sulfate electrolyte in the copper sulfate electrolyte tank is delivered to the electrolytic cell through the delivery pump and the delivery pipeline; The copper sulfate electrolyte in the electrolytic cell flows back to the copper sulfate electrolyte tank through the delivery pipeline to achieve circulation.

[0012] Further, in the step S1, the concentration of the copper sulfate electrolyte in the copper sulfate electrolyte tank is 150 - 200 g / L.

[0013] Further, in the step S3, the current density is 200 - 300 A / m².

[0014] Further, in the step S4, the preset peeling thickness of the deposited copper is 2 - 3 cm.

[0015] Further, in the step S4, the drying method includes natural air drying.

[0016] Further, in the step S4, the detection method includes spectral detection.

[0017] Compared with the prior art, the beneficial effects of the present invention are: 1. In the present invention, an anodic slime upward delivery membrane with its bottom not in contact with the electrolytic cell is arranged between the crude copper anode material and the cation exchange membrane. The anodic slime upward delivery membrane is composed of a composite support layer, a functional gas-producing layer, and a diversion layer. Among them, the support layer is a PTFE film, the functional gas-producing layer is a ruthenium-doped titanium dioxide ceramic matrix loaded with nano-platinum particles, and the diversion layer is a PAN fiber felt. During the electrolytic extraction process of 7N ultra-high purity copper, the PAN fiber felt has hydrophilicity, can form an electrolyte diversion channel, and avoid affecting the flow of the electrolyte. The nano-platinum catalyst catalyzes the electrolysis reaction of water in the electrolyte to generate oxygen and overflow. The overflowing oxygen will generate an upward thrust during the rising process, driving the incoming anodic slime to move upward and be collected. The PTFE film has stable supportability, that is, it can realize the automatic cleaning of the anodic slime, avoid frequent interruption of the reaction, and improve the extraction efficiency of 7N ultra-high purity copper.

[0018] 2. The diversion layer of the anodic slime upward delivery membrane of the present invention, that is, the PAN fiber felt, not only has a diversion function but also has a filtering function, can avoid too large anodic slime from directly entering the ruthenium-doped titanium dioxide ceramic matrix loaded with nano-platinum particles to block the upward movement channel, and ensure the upward delivery effect of the anodic slime.

[0019] 3. The functional gas-producing layer of the anodic slime upward delivery membrane of the present invention, that is, the ruthenium-doped titanium dioxide ceramic matrix loaded with nano-platinum particles, while generating oxygen to produce an upward thrust to drive the anodic slime to move upward, can drive the flow of the electrolyte, play a stirring role, make the ions in the electrolyte more evenly distributed, reduce the phenomenon of concentration polarization, and improve the current efficiency and copper deposition quality. Description of the Drawings

[0020] Figure 1 is the flowchart of the method of the present invention; Figure 2 is the preparation flowchart of the anodic slime upward delivery membrane of the present invention; Figure 3 is the collection flowchart of the anodic slime collection mechanism of the present invention; Figure 4 is the circulation flowchart of the copper sulfate electrolyte circulation mechanism of the present invention. Detailed Embodiments

[0021] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0022] The present invention provides the following technical solutions: A 7N ultra-high purity copper extraction process includes the following steps: S1: Prepare an electrolytic cell, an anodic slime upward delivery membrane, a cation exchange membrane, an anodic slime collection mechanism, a crude copper anode material, a pure copper cathode material, and a copper sulfate electrolyte circulation mechanism. Among them, the anodic slime upward delivery membrane includes a composite support layer, a functional gas generation layer, and a diversion layer; The support layer is a PTFE film, the functional gas generation layer is a ruthenium-doped titanium dioxide ceramic matrix loaded with nano-platinum particles, and the diversion layer is a PAN fiber felt; The preparation of the anodic slime upward delivery membrane includes the following steps: Use an extrusion molding process to make a PTFE resin into a film with a uniform thickness, and then perform a stretching treatment to improve its strength and porosity as the support layer; Extrusion molding means that with the extrusion action of a screw or a plunger, the PTFE resin in a viscous flow state passes through a die with a specific shape at a certain temperature and pressure, so as to continuously form a PTFE film with a constant cross-sectional shape; Pre-forming stage: The barrel temperature is controlled at 350 - 380 °C, the mold temperature is controlled at 350 - 380 °C, the extrusion pressure is controlled at 10 - 50 MPa, and the extrusion speed is controlled at 0.1 - 1 m / min; Stretching treatment stage: The preheating temperature is controlled at 280 - 320 °C, the longitudinal stretching temperature is controlled at 300 - 340 °C, the transverse stretching temperature is controlled at 280 - 320 °C, the longitudinal stretching multiple is controlled at 3 - 10 times, the transverse stretching multiple is controlled at 2 - 8 times, and the stretching speed is controlled at 1 - 10 m / min; Forming stage: The forming temperature is controlled at 320 - 360 °C; Prepare a ruthenium-doped titanium dioxide ceramic matrix through a sol-gel process, and then load nano-platinum particles into the pores of the ceramic matrix through an impregnation method as the functional gas generation layer; The sol-gel process means that metal alkoxides or inorganic salts and other precursors are dissolved in a solvent, and through hydrolysis and polycondensation reactions, a sol is gradually formed. The sol further polymerizes to form a gel with a three-dimensional network structure, and then through processes such as drying and heat treatment, the required material is obtained. Specifically: Add tetrabutyl titanate with a volume ratio of 1:3 to absolute ethanol, stir while adding, and after uniformity, add glacial acetic acid with a molar ratio of 1:1 to tetrabutyl titanate as a chelating agent to control the hydrolysis rate of tetrabutyl titanate, and continue to stir for 30 - 60 min to form a uniform and transparent solution A; Dissolve ruthenium trichloride in absolute ethanol, and at the same time add deionized water with a molar ratio of 2:1 to tetrabutyl titanate, and stir evenly to form solution B; While stirring vigorously, solution B was dropped into solution A at a dropping rate controlled at 1 - 2 drops / s. After dropping, stirring was continued for 2 - 4 h to fully mix the solution evenly, obtaining a stable precursor solution; The precursor solution was left to stand and age at room temperature for 12 - 24 h. During the aging process, hydrolysis and polycondensation reactions gradually occurred in the solution, forming a sol; The sol was placed in a constant temperature drying oven at 40 - 60 °C for 24 - 48 h. As the hydrolysis and polycondensation reactions continued, the sol gradually transformed into a gel; The gel was taken out of the drying oven and naturally dried at room temperature, then placed in an oven at 80 - 120 °C for drying for 12 - 24 h, and then placed in a high-temperature furnace. It was heated at a heating rate of 1 - 5 °C / min to 700 - 900 °C and held for 2 - 4 h to completely crystallize titanium dioxide and simultaneously uniformly dope ruthenium into the titanium dioxide lattice; After the heat treatment ended, it was slowly cooled to room temperature at a rate of 1 - 5 °C / min, obtaining a ruthenium-doped titanium dioxide ceramic matrix; The impregnation method is a method of obtaining a functional gas-producing layer by immersing the ruthenium-doped titanium dioxide ceramic matrix in a platinum precursor solution, enabling the platinum precursor solution to adhere to the surface or pores of the ruthenium-doped titanium dioxide ceramic matrix and undergoing subsequent treatments such as drying, calcination, and reduction; The impregnation temperature was controlled at 20 - 25 °C, and the impregnation time was controlled at 12 - 24 h; The prepared functional gas-producing layer was laminated with the support layer through a hot pressing process; The hot pressing process refers to a method of using high temperature to make the functional gas-producing layer and the support layer reach a plastic state or a softening state, and at the same time applying pressure to promote their tight combination and forming; The hot pressing temperature was controlled at 150 - 180 °C, and the hot pressing pressure was controlled at 2 - 5 MPa; A PAN fiber mat was prepared through an electrospinning process as the flow guiding layer; Electrospinning refers to a method of applying a force to a PAN solution using a high-voltage electrostatic field. When the electric field force is large enough, it will overcome the surface tension of the PAN solution, causing the charged liquid to form a jet from the spinneret. The jet will undergo unstable oscillation and stretching in the electric field, and at the same time the PAN solution continuously volatilizes and cools, finally forming nanofibers on the receiving device; The voltage was controlled at 10 - 25 kV, the flow rate of the spinneret was controlled at 0.5 - 2 mL / h, the spinning temperature was controlled at 20 - 30 °C, and the spinning humidity was controlled at 30% - 60%; The flow guiding layer was bonded to the laminated support layer and functional gas-producing layer through an adhesive to form a multi-layer composite separator, namely the anode slime up-feed membrane; The anode slime collection mechanism includes a suction pump, a collection box, a filter screen, and a collection pipe. One end of the collection box is connected to the suction pump, the filter screen is connected inside the collection box, the other end of the collection box is connected to the collection pipe, and the collection pipe is located above the anode slime upward feeding film. Start the suction pump to create negative pressure in the collection box and the collection pipe. The anode slime on the anode slime upward feeding film is sucked into the collection box through the collection pipe. The copper sulfate electrolyte circulation mechanism includes a copper sulfate electrolyte tank, a delivery pump, and delivery pipes. Both ends of the copper sulfate electrolyte tank are connected to the delivery pipes. One end of the delivery pipe is connected to one side of the electrolytic cell, the other end of the delivery pipe is connected to the delivery pump, the other end of the delivery pump is connected to the delivery pipe, and the other end of the delivery pipe is connected to the other side of the electrolytic cell. The copper sulfate electrolyte in the copper sulfate electrolyte tank is delivered into the electrolytic cell through the delivery pump and the delivery pipes. The copper sulfate electrolyte in the electrolytic cell flows back to the copper sulfate electrolyte tank through the delivery pipe to achieve circulation. The concentration of the copper sulfate electrolyte in the copper sulfate electrolyte tank is 150 - 200 g / L. S2: Install the anode slime upward feeding film and the cation exchange membrane on both sides inside the electrolytic cell with a gap in the middle. The support layer of the anode slime upward feeding film faces the cation exchange membrane. There is a gap between the bottom end of the anode slime upward feeding film and the bottom end of the electrolytic cell. Install the anode slime collection mechanism above the anode slime upward feeding film. Install the crude copper anode material on the side of the electrolytic cell interior close to the diversion layer of the anode slime upward feeding film. Install the pure copper cathode material on the side of the electrolytic cell interior close to the cation exchange membrane. Install the copper sulfate electrolyte circulation mechanism on the electrolytic cell, circulate and deliver the copper sulfate electrolyte into the electrolytic cell interior. Connect the crude copper anode material to the positive pole of the power supply, connect the pure copper cathode material to the negative pole of the power supply, and construct the structure for electrolytic extraction of 7N ultra-high purity copper. S3: Start the power supply with a current density of 200 - 300 A / m². The copper atoms in the crude copper anode material lose electrons under the action of the electric field and turn into copper ions entering the electrolyte. Along with the circulating electrolyte, they flow towards the pure copper cathode material, gain electrons on the surface of the pure copper cathode material and are reduced to copper atoms and deposited. The inactive impurities including gold and silver in the crude copper anode material become anode slime and deposit. The deposited anode slime enters the gap between the anode slime upward feeding film and the electrolytic cell under the driving action of the circulating electrolyte. The functional gas-producing layer of the anode slime upward feeding film generates bubbles, and an upward thrust is generated during the rising of the bubbles, pushing the anode slime entering the anode slime upward feeding film to move upward and be collected by the anode slime collection mechanism. S4: When the copper deposited on the pure copper cathode material reaches 2 - 3 cm, turn off the power supply, take out the pure copper cathode material, strip the copper sheet, wash it, air-dry it naturally, and conduct spectral detection. If the 7N purity is not achieved, use the copper sheet as the anode material and repeat the above steps until the 7N purity is reached.

[0023] Although embodiments of the present invention have been shown and described, those of ordinary skill in the art will appreciate that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A 7N ultra-high purity copper extraction process, characterized in that: The following steps are involved: S1: preparing an electrolytic cell, an anode mud transporting membrane, a cation exchange membrane, an anode mud collecting mechanism, a crude copper anode material, a pure copper cathode material and a copper sulfate electrolyte circulation mechanism, wherein the anode mud transporting membrane comprises a composite support layer, a functional gas production layer and a guide layer; S2: Install the anode mud transport membrane and the cation exchange membrane on both sides of the electrolytic cell, install the anode mud collection mechanism above the anode mud transport membrane, install the crude copper anode material in the electrolytic cell close to the anode mud transport membrane guide layer, install the pure copper cathode material in the electrolytic cell close to the cation exchange membrane, install the copper sulfate electrolyte circulation mechanism on the electrolytic cell, connect the crude copper anode material to the positive electrode of the power supply, and connect the pure copper cathode material to the negative electrode of the power supply, so as to construct a structure for electrolytic extraction of 7N ultra-high purity copper; S3: Start the power supply. The copper atoms of the crude copper anode material lose electrons under the action of the electric field and become copper ions that enter the electrolyte. As the circulating electrolyte flows toward the pure copper cathode material, the copper atoms obtain electrons on the surface of the pure copper cathode material and are reduced to copper atoms and deposited. The crude copper anode material including inactive impurities of gold and silver turns into anode mud deposits. The deposited anode mud enters the gap between the anode mud transporting membrane and the electrolytic cell under the driving action of the circulating electrolyte. Bubbles are generated in the functional gas-producing layer of the anode mud transporting membrane. The bubbles generate an upward thrust during their rise, pushing the anode mud that has entered the anode mud transporting membrane to move upward and be collected by the anode mud collecting mechanism. S4: When the copper on the pure copper cathode material is deposited to a preset thickness, turn off the power, take out the pure copper cathode material, peel off the copper sheet, wash, dry, and test. If the purity of 7N is not reached, use the copper sheet as the anode material and repeat the above steps until the purity of 7N is reached.

2. A 7N ultra-high purity copper extraction process according to claim 1, characterized in that: In the step S1, the support layer is a PTFE film, the functional gas-generating layer is a ruthenium-doped titanium dioxide ceramic matrix loaded with nano-platinum particles, and the guide layer is a PAN fiber felt.

3. A 7N ultra-high purity copper extraction process according to claim 2, characterized in that: In step S1, the preparation of anode mud transport membrane includes the following steps: The PTFE resin is made into a film of uniform thickness through an extrusion molding process, and then stretched to increase its strength and porosity, which serves as a support layer; A ruthenium-doped titanium dioxide ceramic matrix is ​​prepared by a sol-gel process, and then nano-platinum particles are loaded into the pores of the ceramic matrix by an impregnation method as a functional gas-generating layer; The prepared functional gas-generating layer is compounded with the supporting layer by a hot pressing process; PAN fiber mat was prepared by electrospinning process as the guide layer; The guide layer is bonded together with the composite support layer and the functional gas production layer by a binder to form a multi-layer composite diaphragm, namely, the anode mud transport membrane.

4. A 7N ultra-high purity copper extraction process according to claim 1, characterized in that: In step S1, the anode mud collection mechanism includes a suction pump, a collection box, a filter and a collection pipe, one end of the collection box is connected to the suction pump, the inside of the collection box is connected to the filter, and the other end of the collection box is connected to the collection pipe, and the collection pipe is located above the anode mud transport membrane; Start the suction pump to create negative pressure in the collection box and collection tube; The anode mud is transported to the membrane and is sucked into the collection box through the collection pipe.

5. A 7N ultra-high purity copper extraction process according to claim 1, characterized in that: In the step S1, the copper sulfate electrolyte circulation mechanism includes a copper sulfate electrolyte tank, a delivery pump and a delivery pipeline, the two ends of the copper sulfate electrolyte tank are connected to the delivery pipeline, one end of the delivery pipeline is connected to one side of the electrolytic cell, the other end of the delivery pipeline is connected to the delivery pump, the other end of the delivery pump is connected to the delivery pipeline, and the other end of the delivery pipeline is connected to the other side of the electrolytic cell; The copper sulfate electrolyte in the copper sulfate electrolyte tank is transported to the electrolytic cell through a transport pump and a transport pipeline; The copper sulfate electrolyte in the electrolytic cell flows back to the copper sulfate electrolyte tank through the delivery pipeline to achieve circulation.

6. A 7N ultra-high purity copper extraction process according to claim 5, characterized in that: In step S1, the concentration of the copper sulfate electrolyte in the copper sulfate electrolyte tank is 150-200 g / L.

7. A 7N ultra-high purity copper extraction process according to claim 1, characterized in that: In step S3, the current density is 200-300 A / m².

8. A 7N ultra-high purity copper extraction process according to claim 1, characterized in that: In the step S4, the deposited copper is preset to have a peeling thickness of 2-3 cm.

9. A 7N ultra-high purity copper extraction process according to claim 1, characterized in that: In step S4, the drying method includes natural drying.

10. A 7N ultra-high purity copper extraction process according to claim 1, characterized in that: In step S4, the detection method includes spectral detection.

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