Slotting method for zinc electrolytic cell with zinc in cathode plate

Abstract

The invention relates to a slotting method for a zinc electrolytic cell with zinc on a negative plate, and belongs to the technical field of zinc electrolysis. The method comprises the following main process steps: before the production of the electrolytic cell is stopped, putting a cathode plate back into the electrolytic cell to start a new electrodeposition period, when a zinc sheet is separated out from the cathode plate but the thickness of the zinc sheet does not meet the zinc stripping requirement, cutting off direct current, stopping the production of the electrolytic cell, then pumping out electrolyte in the electrolytic cell by using a vacuum cell cleaning system, and pouring the electrolyte into the electrolytic cell when the production is recovered, after the electrolytic bath is filled with the electrolyte, the electrolyte is circulated, then the electrolytic bath is connected with direct current and kept electrified for 2 hours, then new liquid is supplemented into the electrolytic bath, and then the current density is gradually increased to synchronously organize bath taking and zinc stripping; according to the invention, by adopting the slotting mode that the cathode plate is provided with zinc, the time for waiting for zinc on the cathode plate is saved, the electrodeposition period is greatly shortened, the power consumption is effectively reduced, the electric efficiency and the production efficiency are improved, the damage to the cathode plate and the generation of a residual zinc plate are avoided, and the zinc stripping difficulty is effectively reduced.

Description

Technical Field

[0001] The invention relates to a method for slotting a zinc electrolytic cell with a cathode plate carrying zinc, and belongs to the technical field of zinc electrolysis. Background Art

[0002] Electrolytic zinc is a method of extracting metallic zinc by electrolysis in the process of wet zinc smelting. In the current electrolytic zinc production process, when planned maintenance or unexpected events require shutdown, the cathode plate is not put back into the electrolytic cell after the zinc flakes are stripped. When the electrolytic cell is reopened after production is resumed, electrolyte is first poured into the electrolytic cell, and the cathode plate that was stripped of zinc flakes before the shutdown is brushed and put back into the electrolytic cell. This process takes 3-5 hours. During this period, the cathode plate is immersed in the acidic electrolyte without power, which can easily cause corrosion of the cathode plate. In addition, after the electrolytic cell is reopened, it is necessary to wait for the cathode plate to be zinced. This process generally takes about 36 hours before zinc stripping can begin. The electrolysis cycle is long, and because the current density increases from low to high and the acid content of the electrolyte increases from low to high during the electrolysis process, the cathode plate has a strong corrosive effect, which will corrode the aluminum oxide film on the surface of the cathode plate, causing the zinc metal precipitated during the electrolysis process to form an alloy with the aluminum plate surface of the cathode plate, so that the zinc flakes precipitated on the cathode plate adhere to the aluminum plate, which makes it difficult to peel off the zinc flakes and easily produce residual zinc plates. It is necessary to organize manual peeling of the zinc flakes, which is labor-intensive. At the same time, the cathode plate is easily damaged during the peeling process, which increases the consumption of the cathode plate. In addition, manual peeling of the zinc flakes will extend the slot extraction cycle (electrolysis cycle), thereby reducing the electrical efficiency and increasing power consumption. Summary of the invention

[0003] In order to overcome the problems existing in the background technology, the present invention proposes a method for grooving a zinc electrolytic cell with zinc on a cathode plate, which saves the time of waiting for zinc on the cathode plate, greatly shortens the electrolysis cycle, effectively reduces power consumption, improves power efficiency and production efficiency, and protects the aluminum plate surface of the cathode plate by the zinc sheet precipitated before the production stoppage during grooving, thereby avoiding corrosion of the cathode plate, thereby avoiding damage to the cathode plate and the generation of residual zinc plate, and effectively reducing the difficulty of zinc stripping.

[0004] To solve the above problems, the present invention is implemented through the following technical solutions:

[0005] A method for slotting a zinc electrolytic cell with a cathode plate having zinc, comprising the following steps:

[0006] S1: Before the electrolytic cell is shut down, the cathode plate is put back into the electrolytic cell to start a new electrolytic cycle;

[0007] S2: When zinc flakes are deposited on the cathode plate in step S1 but the thickness of the zinc flakes does not meet the zinc stripping requirement, the direct current is cut off, the electrolytic cell is stopped, and the cathode plate remains in the electrolytic cell;

[0008] S3: Drain the electrolyte in the electrolytic cell using a vacuum tank cleaning system;

[0009] S4: When resuming production, electrolyte is poured into the electrolytic cell, and the electrolyte ratio is: zinc 50g / L, acid 120g / L;

[0010] S5: After the electrolytic cell is filled with electrolyte, the circulation pump and cooling tower are turned on to circulate the electrolyte;

[0011] S6: The electrolytic cell is connected to direct current with a current density of 200A / ㎡ and kept powered on for 2 hours;

[0012] S7: adding new liquid to the electrolytic cell after the direct current is turned on in step S6;

[0013] S8: Increase the current density by 20A / ㎡ per hour, and gradually increase it to 500A / ㎡;

[0014] S9: while increasing the current density in step S7, the zinc stripping is carried out synchronously.

[0015] Preferably, the current density of the direct current connected in step S6 may also be 150 A / ㎡.

[0016] Preferably, the new liquid added in step S7 is a neutral ZnSO4 solution, and the amount of the new liquid added is adaptively adjusted according to the acid-zinc ratio of the electrolyte.

[0017] Preferably, the current density in step S8 can be increased to 530 A / ㎡.

[0018] The beneficial effects of the present invention are:

[0019] The present invention adopts a cathode plate zinc slotting method in which zinc metal is continuously deposited on the basis of the zinc flakes deposited before production suspension, thereby eliminating the time for waiting for zinc on the cathode plate, greatly shortening the electroplating cycle, effectively reducing power consumption, and improving power efficiency and production efficiency. The zinc flakes deposited before production suspension protect the aluminum plate surface of the cathode plate during slotting, thereby avoiding corrosion of the cathode plate, thereby avoiding damage to the cathode plate and the generation of residual zinc plate, and effectively reducing the difficulty of zinc stripping. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the process flow of the present invention. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical solution, purpose achieved and effect of the present invention clear and easy to understand, the preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings so that technicians can understand.

[0022] It should be noted that in the description of the present invention, unless otherwise clearly defined or specified, the terms “installed”, “connected”, “connected”, “connected”, etc. should be understood in a broad sense, that is, it can be a fixed connection or a detachable connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium.

[0023] In the present invention, if Figure 1 As shown, a method for slotting a zinc electrolytic cell with a cathode plate having zinc comprises the following steps:

[0024] S1: Before the electrolytic cell is shut down, the cathode plate is put back into the electrolytic cell to start a new electrolytic cycle;

[0025] S2: When zinc flakes are deposited on the cathode plate in step S1 but the thickness of the zinc flakes does not meet the zinc stripping requirement, the direct current is cut off, the electrolytic cell is stopped, and the cathode plate remains in the electrolytic cell;

[0026] S3: Drain the electrolyte in the electrolytic cell using a vacuum tank cleaning system;

[0027] S4: When resuming production, electrolyte is poured into the electrolytic cell, and the electrolyte ratio is: zinc 50g / L, acid 120g / L;

[0028] S5: After the electrolytic cell is filled with electrolyte, the circulation pump and cooling tower are turned on to circulate the electrolyte;

[0029] S6: The electrolytic cell is connected to direct current with a current density of 200A / ㎡ and kept powered on for 2 hours;

[0030] S7: adding new liquid to the electrolytic cell after the direct current is turned on in step S6;

[0031] S8: Increase the current density by 20A / ㎡ per hour, and gradually increase it to 500A / ㎡;

[0032] S9: while increasing the current density in step S7, the zinc stripping is carried out synchronously.

[0033] In the above process, through step S1 and step S2, before the electrolytic cell is shut down, the cathode plate is put back into the electrolytic cell, so that a part of zinc flakes can be precipitated on the cathode plate before the production is stopped. Therefore, after the production is resumed, the cathode plate can continue to precipitate zinc metal on the basis of the zinc flakes precipitated before the production is stopped, thereby eliminating the time required to wait for the zinc on the cathode plate after the zinc flakes are stripped in the traditional zinc electrolytic process. After 2 hours of power-on in step S6, the zinc stripping operation can be started, which greatly shortens the electrolysis cycle, can effectively reduce the power consumption caused by the extension of the electrolysis cycle, improves the power efficiency and production efficiency, and has good economic benefits.

[0034] By adopting the method of cathode plate zinc slotting which continues to precipitate zinc metal on the basis of the zinc flakes precipitated before the production stoppage, the zinc flakes precipitated before the production stoppage form a protective effect on the aluminum plate surface of the cathode plate during slotting, thereby avoiding the cathode plate from being soaked in acidic electrolyte when no power is supplied, and avoiding the corrosion of the cathode plate caused by the process of increasing current density from low to high and increasing acid content of the electrolyte from low to high during the electrolysis process. This can effectively avoid the adhesion of the zinc flakes precipitated during the electrolysis process after the slotting to the aluminum plate of the cathode plate, avoid damage to the cathode plate and the generation of residual zinc plate, effectively reduce the difficulty of zinc stripping, and can directly carry out mechanical zinc stripping without manual zinc stripping, thereby reducing labor intensity and saving a lot of time and labor costs.

[0035] In the above process, the current density of the direct current connected in step S6 is 200A / ㎡, so that the electrolysis process of the cathode plate in the electrolytic cell tends to be stable under a lower current density state, thereby facilitating the subsequent increase of the current density to 500A / ㎡ to ensure the smooth progress of the electrolysis process before switching to normal production; as a further improvement of the present design, the current density of the direct current connected in step S6 can also be 150A / ㎡, thereby further improving the stability of the electrolysis process in the first 2 hours of the electrolysis cell power-on without affecting the normal progress of the electrolysis process of the cathode plate, thereby improving the stability during the subsequent increase of the current density.

[0036] As a further improvement of the present design, the new solution added in step S7 is a neutral ZnSO4 solution. The electrolysis principle of the present invention is: cathode: Zn 2+ +2e=Zn, anode: 4OH - -4e=2H2O+O2↑, the zinc ions in the electrolyte obtain 2 electrons, and elemental zinc is precipitated. The zinc ions will be continuously consumed in the electrolytic process. Therefore, after the electrolytic cell is connected to direct current to start the electrolytic process in step S6, it is necessary to continuously add ZnSO4 solution to the electrolytic cell; wherein, the amount of new liquid added is adaptively adjusted according to the acid-zinc ratio of the electrolyte, that is: in the electrolytic process, the zinc and acid contents of the electrolytic waste liquid downstream of the electrolytic cell are analyzed by chemical analysis, and the acid-zinc ratio is calculated as the basis for adjusting the amount of new liquid added. During normal production, the acid-zinc ratio is within the range of 3.0-4.0. When the acid content in the electrolytic waste liquid is high and the zinc content is low, the amount of new liquid added is increased, and when the zinc content in the electrolytic waste liquid is high and the acid content is low, the amount of new liquid added is reduced, thereby maintaining the stability of the electrolytic environment.

[0037] As a further improvement of the present design, the current density in step S8 can be increased to 530 A / ㎡, so that the zinc metal output can be further increased by slightly increasing the current density after the current density is increased to 500 A / ㎡ and normal production is started, while ensuring the stability and safety of the electrolytic process.

[0038] The present invention adopts a cathode plate zinc slotting method in which zinc metal is continuously deposited on the basis of the zinc flakes deposited before production suspension, thereby eliminating the time for waiting for zinc on the cathode plate, greatly shortening the electroplating cycle, effectively reducing power consumption, and improving power efficiency and production efficiency. The zinc flakes deposited before production suspension protect the aluminum plate surface of the cathode plate during slotting, thereby avoiding corrosion of the cathode plate, thereby avoiding damage to the cathode plate and the generation of residual zinc plate, and effectively reducing the difficulty of zinc stripping.

[0039] Finally, it should be noted that although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present invention. Ordinary technicians in the field can change, modify, replace and modify the above embodiments within the scope of the present invention, which should all be included in the scope of protection of this application.

Claims

1. A method for slotting a zinc electrolytic cell with a cathode plate having zinc, characterized in that: The steps include: S1: Before the electrolytic cell is shut down, the cathode plate is put back into the electrolytic cell to start a new electrolytic cycle; S2: When zinc flakes are deposited on the cathode plate in step S1 but the thickness of the zinc flakes does not meet the zinc stripping requirement, the direct current is cut off, the electrolytic cell is stopped, and the cathode plate remains in the electrolytic cell; S3: Drain the electrolyte in the electrolytic cell using a vacuum tank cleaning system; S4: When resuming production, electrolyte is poured into the electrolytic cell, and the electrolyte ratio is: zinc 50g / L, acid 120g / L; S5: After the electrolytic cell is filled with electrolyte, the circulation pump and cooling tower are turned on to circulate the electrolyte; S6: The electrolytic cell is connected to direct current with a current density of 200A / ㎡ and kept powered on for 2 hours; S7: adding new liquid to the electrolytic cell after the direct current is turned on in step S6; S8: Increase the current density by 20A / ㎡ per hour, and gradually increase it to 500A / ㎡; S9: while increasing the current density in step S7, the zinc stripping is carried out synchronously.

2. The method for slotting a zinc electrolytic cell with a cathode plate having zinc according to claim 1, characterized in that: The current density of the direct current connected in step S6 may also be 150 A / ㎡.

3. The method for slotting a zinc electrolytic cell with a cathode plate containing zinc according to claim 1, characterized in that: The new liquid added in step S7 is a neutral ZnSO4 solution, and the amount of the new liquid added is adaptively adjusted according to the acid-zinc ratio of the electrolyte.

4. The method for slotting a zinc electrolytic cell with a cathode plate containing zinc according to claim 1, characterized in that: The current density in step S8 can also be increased to 530 A / ㎡.

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