Electrolytic refining method and device for high-arsenic anode copper

Abstract

The present application relates to copper electrolysis technical field, specifically relates to a kind of high arsenic anode copper electrolytic refining method and device;Sulfuric acid and copper sulfate aqueous solution are configured as electrolyte, and four-component complex additive is added to the electrolyte, and arsenic is controlled by four-component complex additive in cooperation;Electrolyte is circulated and dearsenicated in multistage settlement and filtration dearsenication device, electrolyte is treated in the process of circulation, and arsenic and arsenic compound in electrolyte are separated;The present application solves the technical problem of how to remove arsenic in the process of electrolytic refining.

Description

Technical Field

[0001] This invention relates to the field of copper electrolysis technology, specifically to an electrolytic refining method and apparatus for high-arsenic-content anode copper. Background Technology

[0002] like Figure 1 As shown, electrolytic refining uses copper as the anode, a pure copper plate (or titanium plate) as the cathode, and a solution of copper sulfate and water as the electrolyte. Direct current is applied, and copper dissolves from the anode and precipitates on the cathode. Other base metals with lower potentials cannot precipitate on the cathode and remain in the electrolyte for purification. Precious metals such as gold, silver, selenium, and tellurium settle at the bottom of the electrolytic cell along with the anode mud and are periodically discharged, collected, and extracted.

[0003] According to industry standards, the copper anode plate should contain 99.5% copper (Cu-A1) and 0.15% arsenic, and 99% copper (Cu-A2) and 0.30% arsenic. In actual production, the arsenic content of copper anodes can reach 0.4% to 3.0%. Arsenic is the most harmful impurity in electrolytic refining: arsenic is mainly composed of As... 3+ As 5+ After entering the electrolyte, the morphology readily reacts with Cu. 2+ Simultaneous deposition at the cathode leads to coarse copper grains and burrs and pores on the surface. At the same time, arsenic forms a solid solution in electrolytic copper, causing the arsenic content to exceed the standard (the national standard Cu-CATH-1 requires arsenic ≤5ppm), reducing the conductivity and ductility of copper. Under high arsenic conditions, the oxide layer produced by the passivation of anode copper falls off and mixes into the surface of cathode copper, forming inclusions and pits, further affecting and damaging the appearance and internal quality of electrolytically refined copper.

[0004] In the prior art, anode copper with excessive arsenic content is usually returned to the PS converter for pyrometallurgical arsenic removal, but the pyrometallurgical arsenic removal capacity is limited; therefore, this application proposes a method for removing arsenic in electrolytic refining. Summary of the Invention

[0005] This invention provides an electrolytic refining method and apparatus for high-arsenic-content anode copper, at least solving the problem of how to remove arsenic during the electrolytic refining process.

[0006] The technical solution used in this invention is as follows:

[0007] The first aspect of this application discloses an electrolytic refining method for high-arsenic-content anode copper, characterized by comprising the following steps:

[0008] An aqueous solution of sulfuric acid and copper sulfate was prepared as an electrolyte, and a quaternary composite additive was added to the electrolyte to achieve synergistic arsenic control.

[0009] The quaternary compound additive includes gelatin 10 mg / L, thiourea 1.0 mg / L, casein 5 mg / L, and acid salt 20 mg / L;

[0010] The electrolyte is passed through a multi-stage sedimentation and filtration arsenic removal device for cyclic arsenic removal. During the circulation process, the electrolyte is treated to break the bubble surface and separate arsenic and arsenic-containing compounds from the electrolyte.

[0011] Furthermore, the main components in the electrolyte are controlled as follows: Cu²⁺ concentration is controlled at 40–55 g / L, and H₂SO₄ concentration is controlled at 180–200 g / L.

[0012] Furthermore, the electrolysis process parameters are as follows: cathode current density 130–200 A / m², anode current density 120–190 A / m². 2 Electrolyte temperature 62–70℃, electrolyte circulation flow rate 46 L / (min·tank), tank voltage ≤0.32V, electrolysis cycle 15–18 days.

[0013] The second aspect of this application discloses a multi-stage sedimentation and filtration arsenic removal device, comprising a sedimentation unit and a filtration and defoaming unit connected to the output end of the sedimentation unit; the sedimentation unit is used to separate anode sludge, and the filtration and defoaming unit is used to remove floating impurities and defoam in the electrolyte; the output end of the sedimentation unit is used to connect to an electrolytic cell, and the filtration and defoaming unit includes a primary sedimentation tank and a secondary sedimentation tank, which are connected by a zigzag sedimentation guide pipe; the primary sedimentation tank is provided with an L-shaped sedimentation input pipe, one end of which extends into a... Inside the primary settling tank, the other end of the settling input pipe is located outside the primary settling tank and is used to connect to the output end of the settling unit. An electrolyte delivery pump is installed on the settling input pipe. A primary filter and a secondary filter are installed sequentially on the settling guide pipe, and a bubble-breaking mechanism is installed between the primary filter and the secondary filter. An overflow pipe is installed on the upper side of the secondary settling tank, and the outer side of the overflow pipe is used to connect to the low-level tank. The lower sides of the primary and secondary settling tanks are connected to the anode mud discharge main pipe through the settling tank anode mud discharge pipe, and a valve is installed on the settling tank anode mud discharge pipe.

[0014] Furthermore, the sedimentation unit includes a primary sedimentation tank and a secondary sedimentation tank. The upper side of the primary sedimentation tank is connected to the secondary sedimentation tank through a sedimentation tank connecting pipe, and the upper side of the secondary sedimentation tank is connected to the input end of the filtration and defoaming unit through a sedimentation tank discharge pipe. The bottom of the primary sedimentation tank and the secondary sedimentation tank are connected to the anode mud discharge main pipe through a sedimentation tank anode mud discharge pipe.

[0015] Furthermore, several electrolytic cells are connected in series. A circulating inlet pipe is provided on one side of the electrolytic cell. One end of the circulating inlet pipe is located inside the electrolytic cell, and the other end of the circulating inlet pipe extends into the drain box inlet pipe, which is used to connect with the circulating drain pipe of the previous electrolytic cell. A circulating pump is provided on the circulating inlet pipe. A drain box is provided inside the electrolytic cell. A circulating drain pipe and a drain box inlet pipe are respectively provided on the lower side of the drain box. The drain box inlet pipe is connected to the inside of the electrolytic cell, and the lower end of the circulating drain pipe extends out of the electrolytic cell.

[0016] The beneficial effects achieved by this invention are as follows:

[0017] The quaternary composite additive works synergistically through a closed-loop arsenic control strategy encompassing "bulk arsenic removal in the liquid phase, arsenic locking on the anodic side, and arsenic inhibition on the cathode side": arsenic removal in the liquid phase, and the fourth component's Cl... - The second component reacts with high-valence oxyacid anions of arsenic, antimony, and bismuth to form insoluble salt precipitates; 3+ The first and third components form chelate complexes, with amide / hydroxyl groups binding free arsenic to reduce the concentration of free arsenic ions in the liquid phase. On the anode side, the first and third components flocculate arsenic-containing anode mud, promoting its sedimentation and separation from the electrolyte, thus cutting off the channel for arsenic to return to the liquid phase through the cyclic dissolution of the anode mud. On the cathode side, the first, second, and third components form a composite adsorption film on the cathode surface, physically hindering the absorption of arsenic. 3+ and As 5+ Migration discharge; through multiple electrochemical mechanisms such as increasing the copper deposition overpotential, widening the potential difference between copper and arsenic deposition, and displacing arsenic ions from adsorption at the cathode active site, the co-deposition reaction of arsenic and copper is suppressed.

[0018] For high-arsenic anode copper with a content of 0.5%~3.0%, an in-situ arsenic removal and suppression electrolytic process integrating additives, parameter control, and multi-stage filtration was constructed.

[0019] A quaternary system of gelatin, thiourea, casein, and chloride salts is formulated to synergistically suppress the precipitation of arsenic impurities through multiple dimensions, including complexation, adsorption, and potential regulation.

[0020] It has specific electrolysis current density, temperature, circulation flow rate, and cell voltage matching parameters to adapt to the electrolysis conditions of high arsenic raw materials.

[0021] The electrolyte purification method, which combines staged sedimentation, dual filtration, and defoaming, continuously reduces the amount of arsenic impurities inside the electrolyte. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the electrolytic copper refining process.

[0023] Figure 2 This is a schematic diagram of a single electrolytic cell structure according to the present invention.

[0024] Figure 3 This is a schematic diagram of the multi-stage sedimentation and filtration arsenic removal device of the present invention.

[0025] Figure 4 This is a schematic diagram of the filter and defoaming unit structure of the present invention.

[0026] In the diagram, 1. Primary settling tank; 2. Secondary settling tank; 3. Settling tank connecting pipe; 4. Settling tank discharge pipe; 5. Anode sludge discharge pipe in the settling tank; 6. Anode sludge discharge main pipe; 7. Primary settling trough; 8. Secondary settling trough; 9. Settling guide pipe; 10. Settling input pipe; 11. Electrolyte transfer pump; 12. Primary filter; 13. Secondary filter; 14. Bubble breaking mechanism; 15. Overflow pipe; 16. Anode sludge discharge pipe in the settling trough; 17. Valve; 18. Electrolytic cell; 19. Circulating inlet pipe; 20. Circulating pump; 21. Drainage box; 22. Circulating drainage pipe; 23. Drainage box inlet pipe. Detailed Implementation

[0027] To facilitate understanding of the present invention by those skilled in the art, specific embodiments of the present invention will be described below with reference to the accompanying drawings.

[0028] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. For those skilled in the art, the specific meaning of the above terms in this invention can be understood through the specific circumstances.

[0029] First, the application scenario of this application will be introduced: This invention is applicable to anode copper with high arsenic content, with an arsenic mass fraction of 0.5% to 3.0%, a copper mass fraction ≥97.0%, and containing conventional impurities such as antimony, bismuth, and iron (total impurity mass fraction ≤3%).

[0030] This invention provides an electrolytic refining method for high-arsenic-content anode copper, comprising the following steps:

[0031] An aqueous solution of sulfuric acid and copper sulfate was prepared as an electrolyte, and a quaternary composite additive was added to the electrolyte to achieve synergistic arsenic control.

[0032] The main components of the electrolyte are controlled at: Cu 2+ The concentration is controlled at 40-55 g / L, and the H2SO4 concentration is controlled at 180-200 g / L; the arsenic ion concentration during electrolysis is ≤8 g / L to avoid excessive enrichment of arsenic ions and dilution of copper ion concentration.

[0033] The quaternary compound additive includes gelatin 10 mg / L, thiourea 1.0 mg / L, casein 5 mg / L, and acid salt 20 mg / L;

[0034] The first component, gelatin, was added at a concentration of 10 mg / L (based on the electrolyte volume ratio). Gelatin, when added to the electrolyte, adsorbs and forms a film on the cathode surface, preferentially hindering the absorption of As.3+ and As 5+ The process involves three main steps: first, migration and discharge; second, the complexation of free arsenic by amide and hydroxyl groups; third, refining copper crystals, encapsulating trace amounts of precipitated arsenic and flocculating arsenic-containing anode mud; and fourth, increasing the precipitation potential difference between Cu and As, which has a weak barrier to Cu deposition and a strong barrier to arsenic discharge, forming a gelatin-arsenic weak coordination complex; improving the density of cathode copper crystals, assisting in the settling of anode mud, compensating for the short-term defects of single additives in controlling arsenic, and making the cathode copper surface smooth and free of long particle defects.

[0035] The second component, thiourea ((NH2)2CS), was added at a rate of 1.0 mg / L (based on the electrolyte volume ratio); one component is the combination of C=S atoms and As atoms. 3+ It forms a stable chelate complex to lock in trivalent arsenic; secondly, it increases the copper deposition overpotential and raises the arsenic reduction overpotential; thirdly, it thickens the adsorption film by superimposing with gelatin, blocking the arsenic diffusion channels; and fourthly, it can inhibit the co-dissolution and co-precipitation of arsenic-antimony-bismuth, optimize the morphology of copper grains, reduce the generation of floating anode mud, and enhance the arsenic control effect.

[0036] The third component, casein, is added at a concentration of 5 mg / L (based on electrolyte volume ratio). Its functions include: 1) forming a durable, uniform adsorption film at high temperatures to permanently block arsenic ion discharge; and 2) complexing As with multiple functional groups. 3+ As 5+ Arsenic; third, flocculation and bidirectional regulation of arsenic-containing anode mud to inhibit secondary arsenic dissolution; fourth, repair of cathode defects; stabilization of cathode interface potential to avoid preferential arsenic precipitation due to local high current density.

[0037] The amount of the fourth component acid salt added (based on the electrolyte volume ratio) is 20 mg / L; one is Cl - It forms insoluble arsenate precipitates with high-valence oxyacid anions of As, Sb, and Bi, thus locking in total arsenic in a solid phase; secondly, it stabilizes As. 5+ Suppress As 3+ Disproportionation activation; thirdly, preferential adsorption of cathode active sites, displacing arsenic ions for bulk liquid-phase arsenic removal, and precipitation of Ag. + Pb 2+ Impurities such as arsenic are removed to prevent them from co-evolving with arsenic, thus indirectly ensuring the effectiveness of arsenic control.

[0038] The quaternary arsenic control mechanism is manifested in: liquid-phase bulk arsenic removal (Cl... - Precipitation + thiourea chelation + dual colloidal complexation) → Anode side arsenic locking (flocculation and sedimentation, cutting off circulation) → Cathode side arsenic blocking (adsorption membrane + polarization + site competition), closed-loop arsenic control throughout the entire process.

[0039] The aforementioned quaternary composite additive works synergistically through a closed-loop arsenic control strategy encompassing "liquid-phase bulk arsenic removal, anodic arsenic locking, and cathode-side arsenic inhibition":

[0040] Liquid-phase bulk arsenic removal, the fourth component Cl -The second component reacts with high-valence oxyacid anions of arsenic, antimony, and bismuth to form insoluble salt precipitates; 3+ A chelate complex is formed, and the first and third components chelate free arsenic through amide / hydroxyl groups, thereby reducing the concentration of free arsenic ions from the liquid phase.

[0041] Arsenic is locked on the anode side. The first and third components flocculate the arsenic-containing anode mud, promote its sedimentation and separation from the electrolyte, and cut off the channel for arsenic to return to the liquid phase through the circulation and dissolution of the anode mud.

[0042] Arsenic is blocked on the cathode side by a composite adsorption film formed by the first, second, and third components on the cathode surface, which physically hinders the absorption of arsenic. 3+ and As 5+ Migration discharge; through multiple electrochemical mechanisms such as increasing the copper deposition overpotential, widening the potential difference between copper and arsenic deposition, and displacing arsenic ions from adsorption at the cathode active site, the co-deposition reaction of arsenic and copper is suppressed.

[0043] The electrolysis process parameters are as follows: cathode current density 130~200A / m 2 Anode current density 120–190 A / m 2 The electrolyte temperature is 62-70℃, the electrolyte circulation flow rate is 46L / (min.cell), the cell voltage is ≤0.32V, and the electrolysis cycle is 15-18 days.

[0044] Cathode current density 130–200 A / m², anode current density 120–190 A / m² 2 To avoid arsenic and copper co-deposition due to high current density, resulting in substandard product quality, the electrolyte temperature is 62–70℃. This temperature range balances electrolyte conductivity and additive stability, reducing arsenic ion co-deposition and lowering cell voltage. The electrolyte circulation flow rate is 46L / (min·cell), with the electrolyte circulating from top to bottom to ensure uniform electrolyte composition, prevent localized arsenic ion enrichment, and remove heat generated during electrolysis. The constant electrolyte temperature is approximately 65℃. The cell voltage is ≤0.32V to reduce electrolysis energy consumption and prevent anode passivation from being exacerbated by excessive voltage. The electrolysis cycle is 15–18 days, which can be adjusted according to the arsenic content of the anode copper. If the arsenic content is high, the cycle can be appropriately extended to ensure the quality of the cathode copper.

[0045] The electrolyte is passed through a multi-stage sedimentation and filtration arsenic removal device for cyclic arsenic removal. During the circulation process, the electrolyte is treated to break the bubble surface and separate arsenic and arsenic-containing compounds from the electrolyte.

[0046] To control the arsenic content in the electrolyte, 235 electrolytic cells (18 cells, 3.66 x 1.09 x 1.38 mm) with a total capacity of 1294 m³ were used. 3The electrolyte circulation rate is 45.8 L / (min·tank), and 11.5 L / (min·tank) is drawn from the circulating electrolyte for purification treatment; the total circulating electrolyte is 1292 m³. 3 The electrode solution is circulated once every two hours; to avoid arsenic ion accumulation, 646 ml of the circulating washing solution is treated with arsenic control every hour. 3 / h, completing one round of treatment of all circulating electrolyte within two hours.

[0047] like Figure 3 As shown, the multi-stage sedimentation and filtration arsenic removal device includes a sedimentation unit and a filtration and defoaming unit connected to the output end of the sedimentation unit. The sedimentation unit is used to separate anode sludge, and the filtration and defoaming unit is used to remove floating impurities and defoam in the electrolyte. The output end of the sedimentation unit is used to connect to the electrolytic cell 18. The sedimentation unit includes a primary sedimentation tank 1 and a secondary sedimentation tank 2. The upper side of the primary sedimentation tank 1 is connected to the secondary sedimentation tank 2 through a sedimentation tank connecting pipe 3. The upper side of the secondary sedimentation tank 2 is connected to the input end of the filtration and defoaming unit through a sedimentation tank discharge pipe 4. The bottom of the primary sedimentation tank 1 and the secondary sedimentation tank 2 are connected to the anode sludge discharge main pipe 6 through a sedimentation tank anode sludge discharge pipe 5.

[0048] like Figure 4 As shown, the filtration and defoaming unit includes a primary settling tank 7 and a secondary settling tank 8, which are connected by a zigzag-shaped settling guide pipe 9. An L-shaped settling input pipe 10 is installed inside the primary settling tank 7, with one end extending into the tank and the other end located outside for connection to the output of the settling unit. An electrolyte transfer pump 11 is installed on the settling input pipe 10. A primary filter 12 and a secondary filter 13 are sequentially installed on the settling guide pipe 9. A bubble-breaking mechanism 14 is provided between the primary filter 12 and the secondary filter 13. The bubble-breaking mechanism 14 can be a pipe structure with a flat channel and a bubble-breaking surface. This surface is wide and the liquid flow is slow, so the liquid is thin on this surface and the bubbles will automatically break. An overflow pipe 15 is provided on the upper side of the secondary settling tank 8. The outer side of the overflow pipe 15 is used to connect to the low-level tank. The lower sides of the primary settling tank 7 and the secondary settling tank 8 are connected to the anode mud discharge main pipe 6 through the settling tank anode mud discharge pipe 16. A valve 17 is provided on the settling tank anode mud discharge pipe 16.

[0049] The arsenic removal process of the multi-stage sedimentation and filtration unit is as follows:

[0050] The circulating electrolyte from electrolytic cell 18 first enters the primary settling tank 1, where anode sludge and heavier impurities such as arsenic clumps settle to the bottom and are then sent to the anode sludge discharge main pipe 6 via the anode sludge discharge pipe 5. The upper electrolyte from the primary settling tank 1 enters the secondary settling tank 2 for further separation of anode sludge. The clear liquid separated in the secondary settling tank 2 enters the primary settling tank 7 for a third settling separation. The upper liquid passes through a primary filtration device to intercept most of the air bubbles and floating impurities before entering the bubble-breaking mechanism 14. The bubble-breaking mechanism 14 breaks the air bubbles... The electrolyte breaks down, releasing entrained dust, metals, and ionic impurities such as As2O3 or As2O5. The electrolyte then enters a secondary filtration device to intercept floating harmful impurities left after the bubbles break. Afterward, the electrolyte enters a secondary settling tank 8 for a fourth settling separation. The clear liquid overflows from the upper part of the secondary settling tank 8 to a lower tank, where it is replenished with acid and water, heated, and supplemented with composite additives before being sent to a higher tank and then returned to the electrolytic cell 18 for recycling. The anode sludge separated at each stage of settling is finally sent to an anode sludge storage tank for further treatment and sale.

[0051] Several electrolytic cells are connected in series. Figure 2 The diagram shows a single electrolytic cell 18. A circulation inlet pipe 19 is provided on one side of the electrolytic cell 18. One end of the circulation inlet pipe 19 is located inside the electrolytic cell 18, and the other end extends into a drain box inlet pipe 23, which connects to the circulation drain pipe 22 of the previous electrolytic cell 18. A circulation pump 20 is provided on the circulation inlet pipe 19. A drain box 21 is provided inside the electrolytic cell 18. A circulation drain pipe 22 and a drain box inlet pipe 23 are respectively provided on the lower side of the drain box 21. The drain box inlet pipe 23 communicates with the inside of the electrolytic cell 18, and the lower end of the circulation drain pipe 22 extends out of the electrolytic cell 18. The electrolyte is circulated using a top-in, bottom-out method.

[0052] Implementation of the plan

[0053] This technology is a method for producing qualified cathode copper from arsenic-containing anode copper. It is a summary of experience gained from solving problems encountered in electrolytic refining practice. The main method is to adjust the process parameters to use arsenic-containing anode copper as raw material to produce qualified electrolytically refined copper, use composite additives to inhibit the precipitation reaction of arsenic ions on the cathode, and increase the equipment to isolate arsenic and its compounds from the electrolyte, thereby reducing the contamination of cathode copper by arsenic and its compounds and ensuring the production of qualified electrolytic copper.

[0054] Trial production has begun, with 216 anode plates installed (note: 19 of which are for producing starter plates), totaling 7776 plates with a total weight of 1905.12 tons and 7560 starter plates. The trial was completed on the 16th of this month, producing 1400.26 tons of cathode copper and 502.38 tons of residual cathode.

[0055] Output rate = (1400.26 + 502.38) / {1905.12 × (1 - 0.0224)} ≈ 102.16%;

[0056] Recovery rate = (1400.26 + 502.38) / {1905.12 = 99.86%}

[0057] Please refer to the table below for product quality. The product quality meets the requirements of Cu-CATH-3 (Copper No. 2) standard.

[0058]

[0059] Trial operation has proven that the present invention, a method for producing qualified cathode copper from arsenic-containing anode copper, is successful.

[0060] The above are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. The scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. An electrolytic refining method for high-arsenic-content anode copper, characterized in that, Includes the following steps, An aqueous solution of sulfuric acid and copper sulfate was prepared as an electrolyte, and a quaternary composite additive was added to the electrolyte to achieve synergistic arsenic control. The quaternary compound additive includes gelatin 10 mg / L, thiourea 1.0 mg / L, casein 5 mg / L, and acid salt 20 mg / L; The electrolyte is passed through a multi-stage sedimentation and filtration arsenic removal device for cyclic arsenic removal. During the circulation process, the electrolyte is treated to break the bubble surface and separate arsenic and arsenic-containing compounds from the electrolyte.

2. The electrolytic refining method for high-arsenic-content anode copper according to claim 1, characterized in that, The main components of the electrolyte are controlled to be: Cu 2+ The concentration should be controlled at 40-55 g / L, and the H2SO4 concentration should be controlled at 180-200 g / L.

3. The electrolytic refining method for high-arsenic-content anode copper according to claim 1, characterized in that, The electrolysis process parameters are as follows: cathode current density 130–200 A / m 2 Anode current density 120–190 A / m 2 The electrolyte temperature is 62-70℃, the electrolyte circulation flow rate is 46L / (min.cell), the cell voltage is ≤0.32V, and the electrolysis cycle is 15-18 days.

4. A multi-stage sedimentation and filtration arsenic removal device, comprising a sedimentation unit and a filtration and defoaming unit connected to the output end of the sedimentation unit; the sedimentation unit is used to separate anode sludge, and the filtration and defoaming unit is used to remove floating impurities and defoam in the electrolyte; the output end of the sedimentation unit is used to connect to an electrolytic cell (18), and the filtration and defoaming unit includes a primary sedimentation tank (7) and a secondary sedimentation tank (8), which are connected by a zigzag sedimentation guide pipe (9); an L-shaped sedimentation input pipe (10) is provided in the primary sedimentation tank (7), one end of the sedimentation input pipe (10) extends into the primary sedimentation tank (7), and the other end of the sedimentation input pipe (10) is located in the... The outer side of the primary settling tank (7) is used to connect to the output end of the settling unit. An electrolyte transfer pump (11) is provided on the settling input pipe (10). A primary filter (12) and a secondary filter (13) are provided in sequence on the settling guide pipe (9). A bubble breaking mechanism (14) is provided between the primary filter (12) and the secondary filter (13). An overflow pipe (15) is provided on the upper side of the secondary settling tank (8). The outer side of the overflow pipe (15) is used to connect to the low-level tank. The lower sides of the primary settling tank (7) and the secondary settling tank (8) are connected to the anode mud discharge main pipe (6) through the settling tank anode mud discharge pipe (16). A valve (17) is provided on the settling tank anode mud discharge pipe (16).

5. The arsenic removal device with multi-stage sedimentation and filtration according to claim 4, characterized in that, The settling unit includes a primary settling tank (1) and a secondary settling tank (2). The upper side of the primary settling tank (1) is connected to the secondary settling tank (2) through a settling tank connecting pipe (3). The upper side of the secondary settling tank (2) is connected to the input end of the filter and defoaming unit through a settling tank discharge pipe (4). The bottom of the primary settling tank (1) and the secondary settling tank (2) are connected to the anode mud discharge main pipe (6) through a settling tank anode mud discharge pipe (5).

6. The arsenic removal device with multi-stage sedimentation and filtration according to claim 4, characterized in that, Several electrolytic cells (18) are connected in series. A circulating inlet pipe (19) is provided on one side of the electrolytic cell (18). One end of the circulating inlet pipe (19) is located inside the electrolytic cell (18), and the other end of the circulating inlet pipe (19) extends out to the drain box inlet pipe (23), which is used to connect with the circulating drain pipe (22) of the previous electrolytic cell (18). A circulating pump (20) is provided on the circulating inlet pipe (19). A drain box (21) is provided inside the electrolytic cell (18). A circulating drain pipe (22) and a drain box inlet pipe (23) are respectively provided on the lower side of the drain box (21). The drain box inlet pipe (23) is connected to the inside of the electrolytic cell (18), and the lower end of the circulating drain pipe (22) extends out of the electrolytic cell (18).

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