Parallel flow copper electrolytic refining process

Abstract

This invention belongs to the field of metal refining processes and provides a parallel flow copper electrolytic refining process. The process involves setting up a balance tank outside the copper electrolytic cell, with crude copper anode plates and stainless steel cathode plates alternately arranged inside the cell and guided by flow guides. A cathode-wall flow channel is formed between the flow guides and the cell wall. Slit nozzles are set on the flow guides along the length of the cell, allowing the electrolyte to be sprayed from the cell side onto the cathode surface and form a parallel flow along the cathode wall. An anode collecting tank is set at the bottom of the copper electrolytic cell. A hydrodynamic barrier is constructed by adjusting the pressure difference between the cathode-wall flow channel and the anode collecting tank, inhibiting the migration of anode sludge to the cathode. The impurity-rich electrolyte from the anode collecting tank is introduced into an online impurity removal unit for treatment and then returned to the balance tank. After mixing with the electrolyte in the cathode circulation branch, it re-enters the cathode-wall flow channel, thereby obtaining cathode copper with uniform composition and controlled impurities.

Description

Technical Field

[0001] This invention belongs to the field of metal refining processes and relates to a parallel flow copper electrolytic refining process. Background Technology

[0002] Wet electrolytic copper refining is a key process for obtaining high-purity cathode copper. Traditional processes typically involve suspending crude copper anode plates and insoluble cathode plates parallel to each other within the same electrolytic cell, maintaining copper ion supply and removing impurities through overall electrolyte circulation. Existing technologies often employ a side or top inlet and bottom outlet method for the electrolyte. The flow pattern of the electrolyte within the electrode gap is significantly affected by the cell shape, the location of the liquid distribution port, and the state of anode mud deposition. Uneven flow velocity and component distribution are prone to occur on the cathode surface, resulting in uneven cathode copper thickness, significant edge effects, and severe local concentration polarization.

[0003] To improve mass transfer conditions, existing technologies have attempted to adjust the flow field by increasing the overall circulation flow rate, installing simple guide plates or rectifier grids in the inter-electrode gap, and optimizing the tank size. However, the electrolyte near the cathode remains dominated by turbulent reflux, making it difficult to form a stable and controlled wall-attached flow layer on the large cathode surface. Simultaneously, insoluble and difficult-to-treat impurities such as antimony and bismuth generated from anode dissolution continuously accumulate in the electrolyte, and anode sludge accumulates at the bottom of the tank and near the anode. When overall circulation is strengthened or local turbulence is enhanced, anode sludge particles are easily entrained and migrate to the cathode region, affecting the purity and surface quality of the cathode copper. Furthermore, existing copper electrolytic refining methods mostly employ single-loop circulation, with the anode and cathode regions sharing a single circulation system, making it difficult to differentiate flow rate and composition control for impurity-rich regions and the area near the cathode. Some technologies mitigate the impact of anode sludge on the cathode by adding diaphragms or complex internal components, but this leads to problems such as complex equipment structure, difficult operation and maintenance, and increased voltage loss. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a parallel flow copper electrolytic refining process. This invention proposes a parallel flow copper electrolytic refining process to improve the problems of uneven cathode flow field, easy anode mud entrapment, and difficulty in zoned adjustment of impurities. This process sets up a slit nozzle and a wall-mounted flow channel on the back of the cathode, and forms a double circulation with the anode liquid collection tank and balance tank at the bottom of the tank. The cathode area and the anode impurity-rich area are zoned and controlled through hydrodynamic barriers and online impurity removal, thereby meeting the needs of actual production.

[0005] To achieve this objective, the present invention provides a parallel flow copper electrolytic refining process, the process comprising:

[0006] a) Tank and electrode arrangement steps: Add an electrolyte containing copper sulfate and sulfuric acid to the copper electrolytic cell. Set up a balance tank outside the copper electrolytic cell and connect it to the copper electrolytic cell through a pipeline. Alternately suspend the anode plate and cathode plate inside the copper electrolytic cell. Set a guide plate along the height direction on the side of each cathode plate away from the adjacent anode plate. A cathode wall-attached flow channel extending along the length direction of the cathode plate is formed between the guide plate and the side wall of the copper electrolytic cell. The guide plate is provided with multiple slit nozzles extending along the length direction of the cathode plate. Set an anode collection tank at the bottom of the copper electrolytic cell along the length direction of the anode plate.

[0007] b) In the cathode-wall parallel flow circulation step, the electrolyte from the balance tank is pumped into the inlet manifold at one end of the copper electrolytic cell via the first circulation pump. The inlet manifold is connected to the cathode-wall flow channel. The electrolyte is sprayed onto the two sides of the cathode plate through the slit nozzle and flows through the cathode-wall flow channel on both sides of the cathode plate. After passing through the cathode plate, it flows back to the balance tank through the outlet manifold at the other end of the copper electrolytic cell, forming the first circulation loop.

[0008] c) Anode impurity-rich electrolyte circulation and impurity removal step: The electrolyte in the anode collecting tank is drawn out by the second circulation pump, sent to the online impurity removal unit for treatment, and then returned to the balance tank to form the second circulation branch.

[0009] d) Cooperative cyclic electrolysis step: During the electrolysis process, the first circulation loop and the second circulation branch are run simultaneously to electrolytically refine the anode plate and obtain electrolytic cathode copper on the cathode plate.

[0010] In this invention, the anode plate is a crude copper anode plate, and the cathode plate is a stainless steel cathode plate. Under the action of an applied current, metallic copper on the anode side dissolves, forming positively charged copper ions and electrons. The electrons are transported to the cathode via an external circuit. Insoluble metal oxides, intermetallic compounds, and noble metal particles in the anode lose their support and detach from the anode surface, forming anode sludge deposited below the anode and at the bottom of the tank. Soluble impurities in the anode, such as antimony and bismuth, enter the electrolyte in the form of their respective cations, forming coordination structures or basic salt species with sulfate and other anions, and participating in migration in the electrolyte liquid phase. Copper ions on the cathode side accept electrons at the cathode surface and undergo reduction, forming a metallic copper deposition layer; a mass transfer boundary region consisting of a convection layer, a transition layer, and a diffusion layer is formed near the cathode surface.

[0011] A guide plate is installed on the back of the cathode to form a wall-attached flow channel. The electrolyte is injected tangentially into the cathode through a slit nozzle and flows along the cathode surface, forming a thin concentration boundary layer near the cathode surface. Copper ions enter this boundary layer from the bulk fluid region through diffusion and convection, weakening the concentration gradient near the cathode reaction region and increasing the flux of copper ions at the cathode surface. The fluids in the wall-attached flow channels on both sides of the cathode undergo lateral mixing in the direction of the slit nozzle spacing and height. The compositional differences of the electrolyte in contact with different positions on the cathode decrease, and the additives, acidity, and the ratio of copper ions to impurity ions tend to stabilize near the cathode surface.

[0012] The lower edge of the guide plate is lower than the lower edge of the anode and has an opening between it and the bottom of the tank. The cathode wall-mounted flow channel and the anode collection tank are connected through the bottom. With the flow rates of the first circulation loop and the second circulation branch, the static pressure in the cathode wall-mounted flow channel area is higher than that in the anode collection tank area. A slow seepage flow is formed at the bottom opening from the cathode side to the anode collection tank side. The mainstream direction of the electrolyte in the cathode wall-mounted flow channel extends along the cathode, while the mainstream direction of the electrolyte in the anode collection tank flows along the bottom of the tank towards the collection area. A shear layer is formed between the two within the frame-shaped guide structure. After the anode mud particles detach near the anode, they move towards the bottom of the tank under gravity, enter the low-velocity zone in the baffled flow channel, and deposit. The area near the suction port is dominated by dissolved metal ions, with a low suspended solids content. The proportion of solid impurities in the electrolyte drawn from the collection tank by the second circulation branch is reduced.

[0013] The first circulation loop supplies electrolyte from the balancing tank to the cathode wall channel. This loop has a short circulation path and primarily serves to replenish copper ions and additives to the cathode. The second circulation branch draws electrolyte rich in antimony, bismuth, and other impurity ions from the anode collecting tank and enters the online impurity removal unit. In the chelating resin section or neutralization precipitation section, antimony, bismuth, and other impurity ions are removed from the electrolyte through complexation adsorption or the formation of insoluble precipitates. The discharged electrolyte returns to the balancing tank and mixes with the electrolyte returned from the first circulation loop. The concentrations of copper ions and impurity ions in the electrolyte in the balancing tank reach a dynamic equilibrium under the combined action of the first and second circulation loops. The ratio of copper ion to impurity ion concentrations in the electrolyte entering the cathode wall channel is maintained within a range conducive to selective electrodeposition. The local concentrations of antimony, bismuth, and other impurities on the cathode surface cannot reach the conditions required for reduction or co-deposition, making them more likely to remain in the solution or enter the impurity removal unit via the second circulation branch.

[0014] Online sensors installed in the balancing tank continuously monitor the concentrations of copper ions, acidity, and impurity ions. The control system adjusts the speeds of the first and second circulation pumps based on the monitoring results. Changes in the flow rate of the first circulation loop primarily affect the linear velocity and boundary layer thickness in the cathode wall-mounted channel, while changes in the flow rate of the second circulation branch primarily affect the renewal rate of impurity ions in the anode collecting tank and the flux entering the impurity removal unit. Flow pulses are created by periodically increasing the flow rate of the first circulation pump. This causes a short-term increase in velocity near the cathode surface, a periodic decrease in the diffusion layer thickness, and significant shear forces on existing dendrites or coarse crystal regions. Local current distribution expands towards a planar shape, and the crystal growth morphology of the cathode copper layer evolves towards a denser and smoother direction. The switching between inlet and outlet liquids along the tank length causes a periodic reversal of the mainstream flow direction in the cathode wall-mounted channel. Different positions on the cathode alternately occupy positions near the inlet or outlet at different stages. Local copper ion concentrations and additive concentrations experience different time series, resulting in a more balanced spatial distribution of the long-term accumulated charge flux. The thickness difference between the front and back of the cathode caused by unidirectional flow weakens, and the spatial distribution of impurities in the cathode copper tends to be more uniform.

[0015] Preferably, in the steps of arranging the tank and electrodes: the concentration of copper ions in the electrolyte is 35-45 g / L, the concentration of sulfuric acid is 160-210 g / L, the concentration of nickel ions is 5-25 g / L, and the electrolyte temperature is 58-65℃; the anode plate is a crude copper anode plate, the cathode plate is a stainless steel cathode plate, and the electrode spacing between the crude copper anode plate and the stainless steel cathode plate is 30-45 mm.

[0016] Preferably, in the tank and electrode arrangement steps: the cathode wall-mounted flow channel is disposed on both sides of each cathode plate, and the width of the cathode wall-mounted flow channel between the guide plate and the side wall of the copper electrolytic cell is 5-10 mm; the angle between the ejection direction of the slit nozzle and the cathode plate surface is 15°-30°, the slit width of the slit nozzle is 0.5-2.0 mm, and the spacing between adjacent slit nozzles is 5-30 mm.

[0017] Preferably, in the cathode wall-mounted parallel flow circulation step and the anode impurity-rich electrolyte circulation and impurity removal step: the electrolyte linear velocity established in the cathode wall-mounted flow channel in the first circulation loop is 0.25-0.40 m / s; the electrolyte linear velocity in the anode collecting tank in the second circulation branch is 0.05-0.15 m / s; the circulation flow rate of the first circulation loop accounts for 70%-95% of the total circulation flow rate, and the circulation flow rate of the second circulation branch accounts for 5%-30% of the total circulation flow rate.

[0018] Preferably, in the steps of arranging the tank and electrodes and the coordinated circulation electrolysis step: the lower edge of the guide plate corresponding to both sides of each cathode plate is lower than the lower edge of the adjacent crude copper anode plate, and a bottom opening is retained between the lower edge of the guide plate and the bottom of the copper electrolysis tank. The cathode wall-mounted flow channel and the anode collection tank are connected to the main electrolysis gap between the anode plate and the cathode plate through the bottom opening and the slit nozzle in the cathode wall-mounted flow channel, forming a frame-shaped flow guide structure surrounding the three sides of the cathode plate; after the circulation flow of the first circulation loop and the second circulation branch is adjusted, the static pressure formed in the cathode wall-mounted flow channel is higher than the static pressure in the anode collection tank, and the static pressure difference between the two is 0.5-5 kPa.

[0019] Preferably, in the anode impurity-rich electrolyte circulation and impurity removal step: the bottom of the anode collecting tank is provided with at least two baffles arranged along the length of the tank; the liquid inlet of the anode collecting tank is located in the stagnant flow zone after the downstream baffle, and the length of the stagnant flow zone is 10%-40% of the total length of the anode collecting tank.

[0020] Preferably, in the synergistic circulating electrolysis step and the anode-rich electrolyte circulation and impurity removal step: the balance tank is equipped with online sensors for detecting copper ion concentration, sulfuric acid concentration, and impurity ion concentration; the first circulation pump and the second circulation pump are respectively connected to the control system; the control system adjusts the rotation speed of the first circulation pump and the second circulation pump according to the detection results of the online sensors; the copper ion concentration in the balance tank is controlled to be no less than 30 g / L, the antimony ion concentration is controlled to be no more than 0.30 g / L, and the bismuth ion concentration is controlled to be no more than 0.30 g / L; the online impurity removal unit is a selective chelating resin column, and the processing flow rate of the online impurity removal unit is 5%-20% of the total circulating flow rate of the copper electrolytic cell.

[0021] Preferably, in the synergistic cyclic electrolysis step, the electrolysis current density is 320-420 A / m. 2 The copper electrolytic cell is equipped with an online cell voltage detection device, which is connected to the control system. The control system maintains the average cell voltage at 95%-105% of the steady-state average cell voltage and performs flow pulse regulation on the first circulation pump at intervals of 10-30 minutes. In each pulse regulation cycle, the instantaneous flow rate of the first circulation pump is increased to 1.2-2.0 times the steady-state flow rate for a duration of 5-30 seconds.

[0022] Preferably, in the coordinated circulation electrolysis step: an inlet manifold and an outlet manifold are respectively provided at both ends of the copper electrolytic cell. The inlet manifold and the outlet manifold are connected to the first circulation loop through a switching valve group. During the electrolysis process, the switching valve group switches the inlet and outlet ends of the first circulation loop according to a fixed cycle, so that the flow direction of the electrolyte in the cathode wall channel is reversed. The fixed cycle is 12-48 hours, and the total circulation flow rate of the first circulation loop changes by no more than 5% before and after each reversal of the electrolyte flow direction.

[0023] Preferably, the number of copper electrolytic cells is 2-20, and multiple copper electrolytic cells are connected in parallel through the first circulation loop and the second circulation branch, and share the same balance tank and online impurity removal unit;

[0024] In the first circulation loop, a flow control valve is installed in the branch of each copper electrolytic cell. Under steady-state conditions, the circulation flow of the branch of the first circulation loop in each copper electrolytic cell accounts for 5%-20% of the total circulation flow of the first circulation loop.

[0025] A flow control valve is installed in the branch of the second circulation branch in each copper electrolytic cell. Under steady-state conditions, the circulation flow of the second circulation branch in each copper electrolytic cell accounts for 5%-40% of the total circulation flow of the second circulation branch. When the concentration of antimony ions in the corresponding anode collecting tank reaches 0.20-0.30 g / L and / or the concentration of bismuth ions reaches 0.20-0.30 g / L, the circulation flow of the second circulation branch of the copper electrolytic cell is adjusted to 1.2-1.8 times the steady-state circulation flow.

[0026] Compared with the prior art, the beneficial effects of the present invention are as follows: The present invention forms a dual circulation system by setting a slit nozzle and a wall-mounted flow channel on the back of the cathode, and forming a dual circulation system with the anode collection tank at the bottom of the tank and an external balance tank, so that the electrolyte forms a parallel flow at the cathode, reducing concentration polarization and overpotential concentration; the frame-shaped flow guiding structure, together with the sedimentation and flow channel of the anode collection tank, guides the anode sludge to accumulate at the bottom of the tank, and forms a hydrodynamic barrier between the cathode area and the anode area, reducing the migration of anode sludge particles and impurities such as antimony and bismuth to the cathode; the anode electrolyte rich in impurities enters the online impurity removal unit through a dedicated circulation branch and returns to the balance tank after treatment, with impurities circulating and removed on the anode side, and the electrolyte composition on the cathode side remaining stable. Attached Figure Description

[0027] Figure 1 This is a flow chart of the parallel flow copper electrolytic refining process provided in Embodiment 1 of the present invention. Detailed Implementation

[0028] The technical solutions of the present invention will be described in detail below with reference to specific embodiments and accompanying drawings. The embodiments described herein are specific implementations of the present invention, used to illustrate the concept of the present invention; these descriptions are explanatory and exemplary, and should not be construed as limiting the implementation methods or the scope of protection of the present invention. In addition to the embodiments described herein, those skilled in the art can employ other obvious technical solutions based on the content disclosed in the claims and specification of this application. These technical solutions include those that make any obvious substitutions and modifications to the embodiments described herein.

[0029] The chemical reagents used in the embodiments and comparative examples of this invention are all commercially available products and have not undergone any further purification treatment.

[0030] Example 1

[0031] This embodiment provides a parallel flow copper electrolytic refining process, such as... Figure 1 As shown, it specifically includes:

[0032] a) Tank and Electrode Arrangement Steps: An electrolyte containing copper sulfate and sulfuric acid is added to the copper electrolytic cell. A balance tank is installed outside the copper electrolytic cell and connected to it via a pipeline. Coarse copper anode plates and stainless steel cathode plates are alternately suspended inside the copper electrolytic cell. A guide plate is installed along the height direction on the side of each cathode plate facing away from the adjacent anode plate. A cathode-wall flow channel extending along the length of the cathode plate is formed between the guide plate and the side wall of the copper electrolytic cell. Multiple slit nozzles extending along the length of the cathode plate are provided on the guide plate. At the bottom of the copper electrolytic cell, along the length of the anode plate... An anode collecting tank is placed. The electrolyte contains 35 g / L copper ions, 210 g / L sulfuric acid, and 5 g / L nickel ions. The electrolyte temperature is 65°C. The distance between the crude copper anode plate and the stainless steel cathode plate is 30 mm. The cathode wall-mounted flow channel is located on both sides of each cathode plate. The width of the cathode wall-mounted flow channel between the guide plate and the side wall of the copper electrolytic cell is 5 mm. The angle between the ejection direction of the slit nozzle and the surface of the cathode plate is 15°. The slit width of the slit nozzle is 0.5 mm, and the distance between adjacent slit nozzles is 5 mm.

[0033] b) In the cathode-wall parallel flow circulation step, the electrolyte from the balance tank is pumped into the inlet manifold at one end of the copper electrolytic cell via the first circulation pump. The inlet manifold is connected to the cathode-wall flow channel. The electrolyte is sprayed onto the surface of the cathode plate through the slit nozzle and flows through the cathode plate in the cathode-wall flow channel before returning to the balance tank through the outlet manifold at the other end of the copper electrolytic cell, forming the first circulation loop. The electrolyte linear velocity established in the cathode-wall flow channel in the first circulation loop is 0.40 m / s, and the circulation flow rate of the first circulation loop accounts for 95% of the total circulation flow rate.

[0034] c) Anode-rich electrolyte circulation and impurity removal steps: The electrolyte in the anode collecting tank is drawn out by a second circulation pump, sent to an online impurity removal unit for treatment, and then returned to the balance tank, forming a second circulation branch. The linear velocity of the electrolyte in the anode collecting tank in the second circulation branch is 0.15 m / s, and the circulation flow rate of the second circulation branch accounts for 5% of the total circulation flow rate. The bottom of the anode collecting tank is provided with at least two baffles arranged along the length of the tank. The suction port of the anode collecting tank is located in the stagnant flow zone after the downstream baffle, and the length of the stagnant flow zone is 10% of the total length of the anode collecting tank.

[0035] d) Cooperative cyclic electrolysis step: During electrolysis, the first and second circulation loops operate simultaneously to electrolytically refine the crude copper anode plate and obtain electrolytic cathode copper on the cathode plate. The electrolysis current density is 420 A / m. 2 The copper electrolytic cell is equipped with an online cell voltage detection device, which is connected to the control system. The control system maintains the average cell voltage at 95% of the steady-state average cell voltage and performs pulse flow regulation on the first circulation pump at 30-minute intervals. During each pulse regulation cycle, the instantaneous flow rate of the first circulation pump is increased to 1.2 times the steady-state flow rate for 30 seconds. The copper electrolytic cell has an inlet manifold and an outlet manifold at both ends, connected to the first circulation loop via a switching valve assembly. During electrolysis, the switching valve assembly switches the inlet and outlet ends of the first circulation loop at a fixed cycle, reversing the flow direction of the electrolyte in the cathode wall channel. The fixed cycle is 12 hours, and the total circulation flow rate of the first circulation loop changes by no more than 5% before and after each reversal of the electrolyte flow direction.

[0036] In the steps of arranging the tank and electrodes and the coordinated circulation electrolysis step: the lower edge of the guide plate corresponding to each cathode plate is lower than the lower edge of the adjacent crude copper anode plate, and a bottom opening is retained between the lower edge of the guide plate and the bottom of the copper electrolysis tank. The cathode wall-mounted flow channel and the anode collection tank are connected to the main electrolysis gap between the anode plate and the cathode plate through the bottom opening and the slit nozzle in the cathode wall-mounted flow channel, forming a frame-shaped flow guide structure surrounding the three sides of the cathode plate; after the circulation flow of the first circulation loop and the second circulation branch is adjusted, the static pressure formed in the cathode wall-mounted flow channel is higher than the static pressure in the anode collection tank, and the static pressure difference between the two is 0.5 kPa.

[0037] In the aforementioned synergistic circulating electrolysis step and the anode-rich electrolyte circulation and impurity removal step: The balance tank is equipped with online sensors for detecting copper ion concentration, sulfuric acid concentration, and impurity ion concentration; the first and second circulation pumps are respectively connected to the control system, which adjusts the rotation speed of the first and second circulation pumps based on the detection results of the online sensors; the copper ion concentration in the balance tank is controlled to be no less than 30 g / L, the antimony ion concentration is controlled to be no more than 0.30 g / L, and the bismuth ion concentration is controlled to be no more than 0.30 g / L; the online impurity removal unit is a selective chelating resin column, and the processing flow rate of the online impurity removal unit is 20% of the total circulating flow rate of the copper electrolytic cell;

[0038] The number of copper electrolytic cells is two. Multiple copper electrolytic cells are connected in parallel through the first circulation loop and the second circulation branch, sharing the same balancing tank and online impurity removal unit. A flow control valve is installed in the branch of the first circulation loop in each copper electrolytic cell. Under steady-state conditions, the circulation flow rate of the branch of the first circulation loop in each copper electrolytic cell accounts for 5% of the total circulation flow rate of the first circulation loop. A flow control valve is installed in the branch of the second circulation loop in each copper electrolytic cell. Under steady-state conditions, the circulation flow rate of the branch of the second circulation loop in each copper electrolytic cell accounts for 40% of the total circulation flow rate of the second circulation branch. When the antimony ion concentration in the corresponding anode collecting tank reaches 0.20 g / L, the circulation flow rate of the branch of the second circulation loop in that copper electrolytic cell is adjusted to 1.8 times the steady-state circulation flow rate.

[0039] Example 2

[0040] This embodiment provides a parallel flow copper electrolytic refining process, specifically including:

[0041] a) Tank and Electrode Arrangement Steps: An electrolyte containing copper sulfate and sulfuric acid is added to the copper electrolytic cell. A balance tank is installed outside the copper electrolytic cell and connected to it via a pipeline. Coarse copper anode plates and stainless steel cathode plates are alternately suspended inside the copper electrolytic cell. A guide plate is installed along the height direction on the side of each cathode plate facing away from the adjacent anode plate. A cathode-wall flow channel extending along the length of the cathode plate is formed between the guide plate and the side wall of the copper electrolytic cell. Multiple slit nozzles extending along the length of the cathode plate are provided on the guide plate. A slit nozzle is also installed at the bottom of the copper electrolytic cell along the length of the anode plate. The anode collecting tank contains an electrolyte with a copper ion concentration of 45 g / L, a sulfuric acid concentration of 160 g / L, a nickel ion concentration of 25 g / L, and an electrolyte temperature of 58°C. The electrode spacing between the crude copper anode plate and the stainless steel cathode plate is 45 mm. The cathode wall-mounted flow channel is located on both sides of each cathode plate, and the width of the cathode wall-mounted flow channel between the guide plate and the side wall of the copper electrolytic cell is 10 mm. The ejection direction of the slit nozzle has an angle of 30° with respect to the surface of the cathode plate, the slit width of the slit nozzle is 2.0 mm, and the spacing between adjacent slit nozzles is 30 mm.

[0042] b) In the cathode-wall parallel flow circulation step, the electrolyte from the balance tank is pumped into the inlet manifold at one end of the copper electrolytic cell via the first circulation pump. The inlet manifold is connected to the cathode-wall flow channel. The electrolyte is sprayed onto the surface of the cathode plate through the slit nozzle and flows through the cathode plate in the cathode-wall flow channel before returning to the balance tank through the outlet manifold at the other end of the copper electrolytic cell, forming the first circulation loop. The electrolyte linear velocity established in the cathode-wall flow channel in the first circulation loop is 0.25 m / s, and the circulation flow rate of the first circulation loop accounts for 70% of the total circulation flow rate.

[0043] c) Anode-rich electrolyte circulation and impurity removal steps: The electrolyte in the anode collecting tank is drawn out by a second circulation pump, sent to an online impurity removal unit for treatment, and then returned to the balance tank, forming a second circulation branch. The linear velocity of the electrolyte in the anode collecting tank in the second circulation branch is 0.05 m / s, and the circulation flow rate of the second circulation branch accounts for 30% of the total circulation flow rate. The bottom of the anode collecting tank is provided with at least two baffles arranged along the length of the tank. The suction port of the anode collecting tank is located in the stagnant flow zone after the downstream baffle, and the length of the stagnant flow zone is 40% of the total length of the anode collecting tank.

[0044] d) Cooperative cyclic electrolysis step: During electrolysis, the first and second circulation loops operate simultaneously to electrolytically refine the crude copper anode plate and obtain electrolytic cathode copper on the cathode plate. The electrolysis current density is 320 A / m. 2 The copper electrolytic cell is equipped with an online cell voltage detection device, which is connected to the control system. The control system maintains the average cell voltage at 105% of the steady-state average cell voltage and performs pulse flow regulation on the first circulation pump at 20-minute intervals. During each pulse regulation cycle, the instantaneous flow rate of the first circulation pump is increased to 2.0 times the steady-state flow rate for 5 seconds. The copper electrolytic cell has an inlet manifold and an outlet manifold at both ends, connected to the first circulation loop via a switching valve assembly. During electrolysis, the switching valve assembly switches the inlet and outlet ends of the first circulation loop at a fixed cycle, reversing the flow direction of the electrolyte in the cathode wall channel. This fixed cycle is 48 hours, and the total circulation flow rate of the first circulation loop changes by no more than 5% before and after each reversal of the electrolyte flow direction.

[0045] In the steps of arranging the tank and electrodes and the coordinated circulation electrolysis step: the lower edge of the guide plate corresponding to each cathode plate is lower than the lower edge of the adjacent crude copper anode plate, and a bottom opening is retained between the lower edge of the guide plate and the bottom of the copper electrolysis tank. The cathode wall-mounted flow channel and the anode collection tank are connected to the main electrolysis gap between the anode plate and the cathode plate through the bottom opening and the slit nozzle in the cathode wall-mounted flow channel, forming a frame-shaped flow guide structure surrounding the three sides of the cathode plate; after the circulation flow of the first circulation loop and the second circulation branch is adjusted, the static pressure formed in the cathode wall-mounted flow channel is higher than the static pressure in the anode collection tank, and the static pressure difference between the two is 5 kPa.

[0046] In the aforementioned synergistic circulating electrolysis step and the anode-rich electrolyte circulation and impurity removal step: The balance tank is equipped with online sensors for detecting copper ion concentration, sulfuric acid concentration, and impurity ion concentration; the first and second circulation pumps are respectively connected to the control system, which adjusts the rotational speeds of the first and second circulation pumps based on the detection results of the online sensors; the copper ion concentration in the balance tank is controlled to be no less than 30 g / L, the antimony ion concentration is controlled to be no more than 0.30 g / L, and the bismuth ion concentration is controlled to be no more than 0.30 g / L; the online impurity removal unit is a selective chelating resin column, and the processing flow rate of the online impurity removal unit is 5% of the total circulating flow rate of the copper electrolytic cell.

[0047] The number of copper electrolytic cells is 20. Multiple copper electrolytic cells are connected in parallel through the first circulation loop and the second circulation branch, and share the same balancing tank and online impurity removal unit. A flow control valve is installed in the branch of the first circulation loop in each copper electrolytic cell. Under steady-state conditions, the circulation flow of the branch of the first circulation loop in each copper electrolytic cell accounts for 20% of the total circulation flow of the first circulation loop. A flow control valve is installed in the branch of the second circulation loop in each copper electrolytic cell. Under steady-state conditions, the circulation flow of the branch of the second circulation loop in each copper electrolytic cell accounts for 5% of the total circulation flow of the second circulation loop. When the bismuth ion concentration in the corresponding anode collecting tank reaches 0.30 g / L, the circulation flow of the branch of the second circulation loop of the copper electrolytic cell is adjusted to 1.2 times the steady-state circulation flow.

[0048] Example 3

[0049] This embodiment provides a parallel flow copper electrolytic refining process, specifically including:

[0050] a) Tank and Electrode Arrangement Steps: An electrolyte containing copper sulfate and sulfuric acid is added to the copper electrolytic cell. A balance tank is installed outside the copper electrolytic cell and connected to it via a pipeline. Coarse copper anode plates and stainless steel cathode plates are alternately suspended inside the copper electrolytic cell. A guide plate is installed along the height direction on the side of each cathode plate facing away from the adjacent anode plate. A cathode-wall flow channel extending along the length of the cathode plate is formed between the guide plate and the side wall of the copper electrolytic cell. Multiple slit nozzles extending along the length of the cathode plate are provided on the guide plate. A slit nozzle is also installed at the bottom of the copper electrolytic cell along the length of the anode plate. The anode collecting tank contains an electrolyte with a copper ion concentration of 40 g / L, a sulfuric acid concentration of 180 g / L, a nickel ion concentration of 15 g / L, and an electrolyte temperature of 62°C. The electrode spacing between the crude copper anode plate and the stainless steel cathode plate is 38 mm. The cathode wall-mounted flow channel is located on both sides of each cathode plate, and the width of the cathode wall-mounted flow channel between the guide plate and the side wall of the copper electrolytic cell is 8 mm. The ejection direction of the slit nozzle has an angle of 20° relative to the surface of the cathode plate, the slit width of the slit nozzle is 1.2 mm, and the spacing between adjacent slit nozzles is 15 mm.

[0051] b) In the cathode-wall parallel flow circulation step, the electrolyte from the balance tank is pumped into the inlet manifold at one end of the copper electrolytic cell via the first circulation pump. The inlet manifold is connected to the cathode-wall flow channel. The electrolyte is sprayed onto the surface of the cathode plate through the slit nozzle and flows through the cathode plate in the cathode-wall flow channel before returning to the balance tank through the outlet manifold at the other end of the copper electrolytic cell, forming the first circulation loop. The electrolyte linear velocity established in the cathode-wall flow channel in the first circulation loop is 0.30 m / s, and the circulation flow rate of the first circulation loop accounts for 85% of the total circulation flow rate.

[0052] c) Anode-rich electrolyte circulation and impurity removal steps: The electrolyte in the anode collecting tank is drawn out by a second circulation pump, sent to an online impurity removal unit for treatment, and then returned to the balance tank, forming a second circulation branch. The linear velocity of the electrolyte in the anode collecting tank in the second circulation branch is 0.10 m / s, and the circulation flow rate of the second circulation branch accounts for 15% of the total circulation flow rate. The bottom of the anode collecting tank is provided with at least two baffles arranged along the length of the tank. The suction port of the anode collecting tank is located in the stagnant flow zone after the downstream baffle, and the length of the stagnant flow zone is 25% of the total length of the anode collecting tank.

[0053] d) Cooperative cyclic electrolysis step: During electrolysis, the first and second circulation loops operate simultaneously to electrolytically refine the crude copper anode plate and obtain electrolytic cathode copper on the cathode plate. The electrolysis current density is 360 A / m. 2The copper electrolytic cell is equipped with an online cell voltage detection device, which is connected to the control system. The control system maintains the average cell voltage at 98% of the steady-state average cell voltage and performs pulse flow regulation on the first circulation pump at 10-minute intervals. During each pulse regulation cycle, the instantaneous flow rate of the first circulation pump is increased to 1.5 times the steady-state flow rate for 15 seconds. The copper electrolytic cell has an inlet manifold and an outlet manifold at both ends, connected to the first circulation loop via a switching valve assembly. During electrolysis, the switching valve assembly switches the inlet and outlet ends of the first circulation loop at a fixed cycle, reversing the flow direction of the electrolyte in the cathode wall channel. This fixed cycle is 24 hours, and the total circulation flow rate of the first circulation loop changes by no more than 5% before and after each reversal of the electrolyte flow direction.

[0054] In the steps of arranging the tank and electrodes and the coordinated circulation electrolysis step: the lower edge of the guide plate corresponding to each cathode plate is lower than the lower edge of the adjacent crude copper anode plate, and a bottom opening is retained between the lower edge of the guide plate and the bottom of the copper electrolysis tank. The cathode wall-mounted flow channel and the anode collection tank are connected to the main electrolysis gap between the anode plate and the cathode plate through the bottom opening and the slit nozzle in the cathode wall-mounted flow channel, forming a frame-shaped flow guide structure surrounding the three sides of the cathode plate; after the circulation flow of the first circulation loop and the second circulation branch is adjusted, the static pressure formed in the cathode wall-mounted flow channel is higher than the static pressure in the anode collection tank, and the static pressure difference between the two is 2.5 kPa.

[0055] In the aforementioned synergistic circulating electrolysis step and the anode-rich electrolyte circulation and impurity removal step: The balance tank is equipped with online sensors for detecting copper ion concentration, sulfuric acid concentration, and impurity ion concentration; the first and second circulation pumps are respectively connected to the control system, which adjusts the rotational speeds of the first and second circulation pumps based on the detection results of the online sensors; the copper ion concentration in the balance tank is controlled to be no less than 30 g / L, the antimony ion concentration to be no more than 0.30 g / L, and the bismuth ion concentration to be no more than 0.30 g / L; the online impurity removal unit is a selective chelating resin column, and the processing flow rate of the online impurity removal unit is 10% of the total circulating flow rate of the copper electrolytic cell;

[0056] The number of copper electrolytic cells is 10. These cells are connected in parallel via a first circulation loop and a second circulation branch, sharing the same balancing tank and online impurity removal unit. A flow control valve is installed in the branch of the first circulation loop in each copper electrolytic cell. Under steady-state conditions, the circulation flow rate of the branch of the first circulation loop in each copper electrolytic cell accounts for 10% of the total circulation flow rate of the first circulation loop. A flow control valve is also installed in the branch of the second circulation loop in each copper electrolytic cell. Under steady-state conditions, the circulation flow rate of the branch of the second circulation loop in each copper electrolytic cell accounts for 10% of the total circulation flow rate of the second circulation loop. When the antimony ion concentration and bismuth ion concentration in the corresponding anode collecting tank reach 0.25 g / L and 0.25 g / L, the circulation flow rate of the second circulation branch of that copper electrolytic cell is adjusted to 1.5 times the steady-state circulation flow rate.

[0057] Example 4

[0058] This embodiment provides a parallel flow copper electrolytic refining process, specifically including:

[0059] a) Tank and Electrode Arrangement Steps: An electrolyte containing copper sulfate and sulfuric acid is added to the copper electrolytic cell. A balance tank is installed outside the copper electrolytic cell and connected to it via a pipeline. Coarse copper anode plates and stainless steel cathode plates are alternately suspended inside the copper electrolytic cell. A guide plate is installed along the height direction on the side of each cathode plate facing away from the adjacent anode plate. A cathode-wall flow channel extending along the length of the cathode plate is formed between the guide plate and the side wall of the copper electrolytic cell. Multiple slit nozzles extending along the length of the cathode plate are provided on the guide plate. A slit nozzle is also installed at the bottom of the copper electrolytic cell along the length of the anode plate. The anode collecting tank contains an electrolyte with a copper ion concentration of 42 g / L, a sulfuric acid concentration of 195 g / L, a nickel ion concentration of 10 g / L, and an electrolyte temperature of 60°C. The electrode spacing between the crude copper anode plate and the stainless steel cathode plate is 35 mm. The cathode wall-mounted flow channel is located on both sides of each cathode plate, and the width of the cathode wall-mounted flow channel between the guide plate and the side wall of the copper electrolytic cell is 7 mm. The ejection direction of the slit nozzle has an angle of 25° relative to the cathode plate surface, the slit width of the slit nozzle is 0.8 mm, and the spacing between adjacent slit nozzles is 10 mm.

[0060] b) In the cathode-wall parallel flow circulation step, the electrolyte from the balance tank is pumped into the inlet manifold at one end of the copper electrolytic cell via the first circulation pump. The inlet manifold is connected to the cathode-wall flow channel. The electrolyte is sprayed onto the surface of the cathode plate through the slit nozzle and flows through the cathode plate in the cathode-wall flow channel before returning to the balance tank through the outlet manifold at the other end of the copper electrolytic cell, forming the first circulation loop. The electrolyte linear velocity established in the cathode-wall flow channel in the first circulation loop is 0.35 m / s, and the circulation flow rate of the first circulation loop accounts for 90% of the total circulation flow rate.

[0061] c) Anode-rich electrolyte circulation and impurity removal steps: The electrolyte in the anode collecting tank is drawn out by a second circulation pump, sent to an online impurity removal unit for treatment, and then returned to the balance tank, forming a second circulation branch. The linear velocity of the electrolyte in the anode collecting tank in the second circulation branch is 0.08 m / s, and the circulation flow rate of the second circulation branch accounts for 10% of the total circulation flow rate. The bottom of the anode collecting tank is provided with at least two baffles arranged along the length of the tank. The suction port of the anode collecting tank is located in the stagnant flow zone after the downstream baffle, and the length of the stagnant flow zone is 20% of the total length of the anode collecting tank.

[0062] d) Cooperative cyclic electrolysis step: During electrolysis, the first and second circulation loops operate simultaneously to electrolytically refine the crude copper anode plate and obtain electrolytic cathode copper on the cathode plate. The electrolysis current density is 380 A / m. 2 The copper electrolytic cell is equipped with an online cell voltage detection device, which is connected to the control system. The control system maintains the average cell voltage at 102% of the steady-state average cell voltage and performs pulse flow regulation on the first circulation pump at 15-minute intervals. During each pulse regulation cycle, the instantaneous flow rate of the first circulation pump is increased to 1.6 times the steady-state flow rate for 20 seconds. The copper electrolytic cell has an inlet manifold and an outlet manifold at both ends, connected to the first circulation loop via a switching valve assembly. During electrolysis, the switching valve assembly switches the inlet and outlet ends of the first circulation loop at a fixed cycle, reversing the flow direction of the electrolyte in the cathode wall channel. This fixed cycle is 36 hours, and the total circulation flow rate of the first circulation loop changes by no more than 5% before and after each reversal of the electrolyte flow direction.

[0063] In the steps of arranging the tank and electrodes and the coordinated circulation electrolysis step: the lower edge of the guide plate corresponding to each cathode plate is lower than the lower edge of the adjacent crude copper anode plate, and a bottom opening is retained between the lower edge of the guide plate and the bottom of the copper electrolysis tank. The cathode wall-mounted flow channel and the anode collection tank are connected to the main electrolysis gap between the anode plate and the cathode plate through the bottom opening and the slit nozzle in the cathode wall-mounted flow channel, forming a frame-shaped flow guide structure surrounding the three sides of the cathode plate; after the circulation flow of the first circulation loop and the second circulation branch is adjusted, the static pressure formed in the cathode wall-mounted flow channel is higher than the static pressure in the anode collection tank, and the static pressure difference between the two is 1.2 kPa.

[0064] In the aforementioned synergistic circulating electrolysis step and the anode-rich electrolyte circulation and impurity removal step: The balance tank is equipped with online sensors for detecting copper ion concentration, sulfuric acid concentration, and impurity ion concentration; the first and second circulation pumps are respectively connected to the control system, which adjusts the rotation speed of the first and second circulation pumps based on the detection results of the online sensors; the copper ion concentration in the balance tank is controlled to be no less than 30 g / L, the antimony ion concentration is controlled to be no more than 0.30 g / L, and the bismuth ion concentration is controlled to be no more than 0.30 g / L; the online impurity removal unit is a selective chelating resin column, and the processing flow rate of the online impurity removal unit is 15% of the total circulating flow rate of the copper electrolytic cell;

[0065] The number of copper electrolytic cells is 12. Multiple copper electrolytic cells are connected in parallel through the first circulation loop and the second circulation branch, sharing the same balancing tank and online impurity removal unit. A flow control valve is installed in the branch of the first circulation loop in each copper electrolytic cell. Under steady-state conditions, the circulation flow rate of the branch of the first circulation loop in each copper electrolytic cell accounts for 8.3% of the total circulation flow rate of the first circulation loop. A flow control valve is installed in the branch of the second circulation loop in each copper electrolytic cell. Under steady-state conditions, the circulation flow rate of the branch of the second circulation loop in each copper electrolytic cell accounts for 20% of the total circulation flow rate of the second circulation loop. When the antimony ion concentration in the corresponding anode collecting tank reaches 0.22 g / L, the circulation flow rate of the branch of the second circulation loop in that copper electrolytic cell is adjusted to 1.6 times the steady-state circulation flow rate.

[0066] Comparative Example 1

[0067] This comparative example provides a parallel flow copper electrolytic refining process, which differs from Example 1 in that it adopts a traditional single-circulation parallel flow process, without setting up a flow guide plate and cathode wall-mounted flow channel, without setting up a second circulation branch and online impurity removal unit, without setting up a baffle and static flow zone in the anode collection tank, and the electrolyte flows unidirectionally in the main electrolysis gap. Other process parameters and operating conditions are exactly the same as in Example 1.

[0068] Comparative Example 2

[0069] This comparative example provides a parallel flow copper electrolytic refining process, which differs from Example 1 in that, in the tank and electrode arrangement steps, guide plates are not set on both sides of the cathode plate, a cathode wall-attached flow channel is not formed between the guide plates and the side wall of the copper electrolytic cell, and a slit nozzle is not set on the side wall of the copper electrolytic cell. Other process parameters and operating conditions are exactly the same as in Example 1.

[0070] Comparative Example 3

[0071] This comparative example provides a parallel flow copper electrolytic refining process, which differs from Example 1 in that, in the anode rich impurity electrolyte circulation and impurity removal steps, the bottom of the anode collection tank is not equipped with a baffle arranged along the length of the tank. Other process parameters and operating conditions are exactly the same as in Example 1.

[0072] Comparative Example 4

[0073] This comparative example provides a parallel flow copper electrolytic refining process, which differs from Example 1 in that: in the coordinated cyclic electrolysis step, the first circulating pump operates at a constant flow rate throughout the entire electrolysis cycle, and the flow rate of the first circulating pump is not pulsed. Other process parameters and operating conditions are exactly the same as in Example 1.

[0074] The method for testing the purity of cathode copper is as follows: referring to the provisions of GB / T 467-2010 on the inspection of the chemical composition of cathode copper, the cathode copper sample is subjected to chemical analysis or spectroscopic analysis to determine the content of copper and impurity elements. The evaluation index is the mass fraction of copper in the cathode copper, and the unit is mass percentage (%).

[0075] The test method for the content of impurities As+Sb+Bi in cathode copper is as follows: referring to GB / T 467-2010 and the standard for chemical analysis of nonferrous metals, after dissolving the cathode copper sample, the mass fractions of arsenic, antimony and bismuth are determined by inductively coupled plasma atomic emission spectrometry or atomic absorption spectrometry, respectively. The evaluation index is the sum of the mass fractions of As, Sb and Bi or their individual mass fractions, in ppm.

[0076] The method for testing the surface roughness of the cathode is as follows: referring to the provisions of GB / T 1031 on surface roughness measurement, the surface roughness Ra is measured at multiple representative locations on the cathode plate surface using a contact surface profilometer, with the unit being micrometers (μm).

[0077] The method for testing the anode mud entry rate is as follows: After the electrolysis is running stably, the total output of anode mud within a certain period is counted. At the same time, a certain volume of circulating electrolyte sample is collected periodically at the liquid inlet of each anode collection tank. After filtration, drying and weighing, the mass of anode mud carried into the impurity removal unit by the second circulation branch is obtained. The anode mud entry rate is calculated as the ratio of the mass of anode mud entering the second circulation branch to the total output of anode mud in the same period. The evaluation index is the anode mud entry rate, and the unit is mass percentage (%).

[0078] The test results are shown in Table 1.

[0079] Table 1. Test results of cathode deposition quality and anode mud entry rate in Examples 1-4 and Comparative Examples 1-4

[0080]

[0081] As shown in Table 1, compared with Example 1, Comparative Example 1 showed a decrease in cathode copper purity, an increase in total impurity content, an increase in cathode surface roughness, and an increase in anode mud entry rate; Comparative Example 2 showed an increase in total impurity content, an increase in cathode surface roughness, and an increase in anode mud entry rate; Comparative Example 3 showed a decrease in cathode copper purity, an increase in total impurity content, an increase in cathode surface roughness, and an increase in anode mud entry rate; and Comparative Example 4 showed an increase in total impurity content, an increase in cathode surface roughness, and an increase in anode mud entry rate.

[0082] This is because, in Comparative Example 1, a traditional single-cycle process, the electrolyte circulates throughout the tank, resulting in uneven flow velocity distribution between electrodes. Anode sludge is easily entrained and suspended in the main electrolysis zone, while impurities accumulate repeatedly on the cathode side, leading to decreased cathode copper purity and increased total impurity content, surface roughness, and anode sludge entry rate. Comparative Example 2 lacks a cathode wall-mounted flow channel and slit nozzle, resulting in low local flow velocity at the cathode. This makes it difficult to promptly flush the diffusion layer, easily forming granular and streaky deposits, increasing thickness differences, and raising surface roughness. In Comparative Example 3, the anode collection tank lacks a baffle-static flow zone structure, leaving the suction port in the mainstream zone. Anode sludge cannot effectively settle at the bottom of the tank, and solid particles repeatedly enter the impurity removal unit and main electrolysis gap during the second cycle, increasing arsenic, antimony, and bismuth inclusions and co-deposition, leading to increased total impurity content and anode sludge entry rate. Comparative Example 4 did not have flow pulses or periodic flow direction reversals. The flow field on the cathode surface remained in a single direction for a long time. Local concentration polarization gradually accumulated, the copper ion concentration gradient in the plate end region increased, the copper deposition thickness distribution was uneven, and the surface roughness increased.

[0083] The above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A parallel-flow copper electrolytic refining process, characterized in that, The process includes: An electrolyte containing copper sulfate and sulfuric acid is added to a copper electrolytic cell. A balance tank is set outside the copper electrolytic cell and connected to the copper electrolytic cell through a pipeline. Anode plates and cathode plates are alternately suspended in the copper electrolytic cell. A guide plate is set on both sides of each cathode plate. A cathode wall-attached flow channel extending along the length of the cathode plate is formed between the guide plate and the side wall of the electrolytic cell. The guide plate is provided with multiple slit nozzles extending along the length of the cathode plate. An anode collection tank is set at the bottom of the copper electrolytic cell along the length of the anode plate. Electrolyte from the balancing tank is pumped into the inlet manifold at one end of the copper electrolytic cell via the first circulation pump. The inlet manifold is connected to the cathode wall-attached flow channel. The electrolyte is sprayed onto the two sides of the cathode plate through the slit nozzle and flows through the cathode wall-attached flow channel on both sides of the cathode plate. After passing through the cathode plate, it flows back to the balancing tank through the outlet manifold at the other end of the copper electrolytic cell, forming the first circulation loop. The electrolyte in the anode collecting tank is drawn out by the second circulation pump, sent to the online impurity removal unit for treatment, and then returned to the balance tank to form the second circulation branch. During the electrolysis process, the first circulation loop and the second circulation branch are run simultaneously to electrolytically refine the anode plate and obtain electrolytic cathode copper on the cathode plate.

2. The parallel flow copper electrolytic refining process according to claim 1, characterized in that, The concentration of copper ions in the electrolyte is 35-45 g / L, the concentration of sulfuric acid is 160-210 g / L, the concentration of nickel ions is 5-25 g / L, and the electrolyte temperature is 58-65℃. The anode plate is a crude copper anode plate, and the cathode plate is a stainless steel cathode plate. The electrode spacing between the crude copper anode plate and the stainless steel cathode plate is 30-45mm.

3. The parallel flow copper electrolytic refining process according to claim 1, characterized in that, The cathode wall-attached flow channel is set on both sides of each cathode plate, and the width of the cathode wall-attached flow channel between the guide plate and the side wall of the copper electrolytic cell is 5-10mm. The ejection direction of the slit nozzle has an angle of 15°-30° with respect to the surface of the cathode plate, the slit width of the slit nozzle is 0.5-2.0 mm, and the distance between adjacent slit nozzles is 5-30 mm.

4. The parallel flow copper electrolytic refining process according to claim 1, characterized in that, The electrolyte linear velocity established in the cathode-walled flow channel in the first circulation loop is 0.25-0.40 m / s; The linear velocity of the electrolyte in the second circulation branch within the anode collecting tank is 0.05-0.15 m / s; The circulation flow of the first circulation loop accounts for 70%-95% of the total circulation flow, and the circulation flow of the second circulation branch accounts for 5%-30% of the total circulation flow.

5. The parallel flow copper electrolytic refining process according to claim 1, characterized in that, The lower edge of the guide plate on both sides of each cathode plate is lower than the lower edge of the adjacent crude copper anode plate. A bottom opening is retained between the lower edge of the guide plate and the bottom of the copper electrolysis cell. The cathode wall-attached flow channel and the anode liquid collection tank are connected to the main electrolysis gap between the anode plate and the cathode plate through the bottom opening and the slit nozzle in the cathode wall-attached flow channel, forming a frame-shaped guide structure surrounding the three sides of the cathode plate. After the circulation flow rates of the first circulation loop and the second circulation branch are adjusted, the static pressure formed in the cathode wall-mounted flow channel is higher than the static pressure in the anode collection tank, and the static pressure difference between the two is 0.5-5 kPa.

6. The parallel flow copper electrolytic refining process according to claim 1, characterized in that, The bottom of the anode collection tank is provided with at least two baffles arranged along the length of the tank. The suction port of the anode collecting tank is located in the stagnant flow zone after the downstream baffle, and the length of the stagnant flow zone is 10%-40% of the total length of the anode collecting tank.

7. The parallel flow copper electrolytic refining process according to claim 1, characterized in that, The balance tank is equipped with online sensors for detecting the concentration of copper ions, sulfuric acid, and impurity ions. The first circulation pump and the second circulation pump are respectively connected to the control system. The control system adjusts the speed of the first circulation pump and the second circulation pump according to the detection results of the online sensors. The concentration of copper ions in the balance tank is controlled to be no less than 30 g / L, the concentration of antimony ions is controlled to be no more than 0.30 g / L, and the concentration of bismuth ions is controlled to be no more than 0.30 g / L. The online impurity removal unit is a selective chelating resin column, and the processing flow rate of the online impurity removal unit is 5%-20% of the total circulating flow rate of the copper electrolytic cell.

8. The parallel flow copper electrolytic refining process according to claim 1, characterized in that, The current density for electrolysis is 320-420 A / m 2 The copper electrolytic cell is equipped with an online cell voltage detection device, which is connected to the control system. The control system maintains the average tank voltage at 95%-105% of the steady-state average tank voltage, and performs flow pulse regulation on the first circulating pump at intervals of 10-30 minutes. In each pulse regulation cycle, the instantaneous flow rate of the first circulating pump is increased to 1.2-2.0 times the steady-state flow rate for a duration of 5-30 seconds.

9. The parallel flow copper electrolytic refining process according to claim 1, characterized in that, The copper electrolytic cell is provided with an inlet manifold and an outlet manifold at both ends. The inlet manifold and the outlet manifold are connected to the first circulation loop through a switching valve group. During the electrolysis process, the switching valve group switches the inlet end and outlet end of the first circulation loop according to a fixed cycle, so that the flow direction of the electrolyte in the cathode wall channel is reversed. The fixed cycle is 12-48 hours, and the total circulation flow rate of the first circulation loop changes by no more than 5% before and after each reversal of the electrolyte flow direction.

10. The parallel flow copper electrolytic refining process according to claim 1, characterized in that, The number of copper electrolytic cells is 2-20. Multiple copper electrolytic cells are connected in parallel through the first circulation loop and the second circulation branch, and share the same balance tank and online impurity removal unit. In the first circulation loop, a flow control valve is installed in the branch of each copper electrolytic cell. Under steady-state conditions, the circulation flow of the branch of the first circulation loop in each copper electrolytic cell accounts for 5%-20% of the total circulation flow of the first circulation loop. A flow control valve is installed in the branch of the second circulation branch in each copper electrolytic cell. Under steady-state conditions, the circulation flow of the branch of the second circulation branch in each copper electrolytic cell accounts for 5%-40% of the total circulation flow of the second circulation branch. When the concentration of antimony ions in the corresponding anode collecting tank reaches 0.20-0.30 g / L and / or the concentration of bismuth ions reaches 0.20-0.30 g / L, the circulation flow of the branch of the second circulation branch of the copper electrolytic cell is adjusted to 1.2-1.8 times the steady-state circulation flow.

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