Method for electrochemically removing lead dioxide failure coating on surface of anode

Abstract

The invention relates to the technical field of surface treatment of anodes, in particular to a method for electrochemically removing a lead dioxide failure coating on the surface of an anode, which comprises the following steps: S1, pretreating the surface of the anode; s2, preparing an electrolyte; s3, the anode pretreated in the step S1 serves as a cathode, the insoluble anode serves as an anode, the cathode and the anode are arranged in an electrolytic bath containing the electrolyte in the step S2 in a cathode-anode-cathode mode to be powered on, and the lead dioxide failure coating on the surface of the anode is removed; and S4, cleaning the surface of the electrode treated in the S3. According to the method, when the lead dioxide invalid coating on the surface of the anode is removed, the ferrous salt is introduced into the prepared electrolyte, and Fe2 + ions in the ferrous salt can reduce PbO2, so that the removal efficiency of the lead dioxide invalid coating on the surface of the anode is greatly improved, and the treated surface of the anode is clean and free of invalid active layer residues; and the concentration of nitric acid in the prepared electrolyte is reduced, and the anode base material is not damaged on the basis of improving the environment.

Description

Technical Field

[0001] The invention relates to the technical field of anode surface treatment, and in particular to a method for electrochemically removing a lead dioxide failure coating on the anode surface. Background Art

[0002] Lead dioxide has good electrical conductivity similar to that of metals, strong oxidation ability in aqueous solution systems, and can pass large currents. It has long been used as an insoluble anode in the electrolytic industry. With titanium as the substrate, a β-PbO2 layer with good electrical conductivity and corrosion resistance can be deposited on its surface by electroplating. This type of anode is called a new titanium-based lead dioxide anode. During the use of the new titanium-based lead dioxide anode, as the use time increases, the lead dioxide coating on the surface begins to fall off and fail after reaching the end of its life. At this time, the failed anode needs to be repaired and regenerated. When removing the failed lead dioxide coating on the anode surface, the existing technology usually uses a high-concentration nitric acid with a mass fraction of 30% to remove it under electrochemical conditions. Since this method uses pure nitric acid as a solution, the nitric acid concentration is too high, and yellow smoke is continuously generated during the reaction, which causes serious pollution to the environment and great harm to people. In addition, the workpiece is also very susceptible to corrosion, and the removal efficiency is relatively low, which greatly prolongs the repair period of the new titanium-based lead dioxide anode and causes waste of resources.

[0003] In view of the above situation, it is necessary to provide a new method, which not only has the advantages of simple operation, economy, environmental protection, and low cost, but also should meet the requirements of high efficiency and low energy consumption to overcome the defects in the existing process. Summary of the invention

[0004] In order to solve the above problems, the present invention provides a method for electrochemically removing the lead dioxide failure coating on the anode surface. When removing the lead dioxide failure coating on the anode surface, a ferrous salt is introduced into the configured electrolyte. The Fe 2+ The ions can reduce PbO2, greatly improving the removal efficiency of the failed active layer of lead dioxide on the anode surface; and the concentration of nitric acid in the electrolyte configured by the present invention is reduced, and the anode substrate is not damaged on the basis of improving the environment. The treated anode surface is clean and has no failed active layer residue, and does not damage the base material.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A method for electrochemically removing a lead dioxide failure coating on an anode surface comprises the following steps:

[0007] S1. Pre-treating the anode with failed lead dioxide coating on the surface;

[0008] S2. Prepare an electrolyte: mix nitric acid, ferrous salt, citric acid monohydrate and deionized water to obtain an electrolyte;

[0009] The concentration of nitric acid in the electrolyte is 150 g / L, the concentration of ferrous salt is 10-15 g / L, and the concentration of citric acid monohydrate is 40 g / L; the ferrous salt is any one of FeC2O4 or FeCl2·4H2O;

[0010] S3. The anode with the failed lead dioxide coating on the surface after S1 pretreatment is used as a cathode to connect to the negative electrode of the power supply, and an insoluble anode is used as an anode to connect to the positive electrode of the power supply, and the above-mentioned plates are arranged in an electrolytic cell containing S2 electrolyte in a yin-yang-yin manner and energized to remove the failed lead dioxide coating on the anode surface;

[0011] S4. Clean the anode after removing the failed lead dioxide coating on the surface until all the surface residues are rinsed away.

[0012] Preferably, the pretreatment in S1 is specifically as follows: immersing the anode with failed lead dioxide coating on the surface in a deionized water pool, heating the deionized water to 50-60° C., and simultaneously performing ultrasonic vibration for 1-2 hours; and then washing with a high-pressure water gun for 5-10 minutes until the surface residue is washed away and the failed electrode surface is exposed.

[0013] Preferably, when S3 is powered on, the power supply is turned on in constant current mode, and the power supply current density is 200-300A / m 2 .

[0014] Preferably, the sign indicating that the removal of the failed lead dioxide coating on the anode surface in S3 is complete is: the power supply voltage is displayed as 6V or above.

[0015] Preferably, the cleaning in S4 is performed using a high-pressure water gun.

[0016] The beneficial effects of the present invention are as follows: 1) when electrochemically removing the lead dioxide failure coating on the anode surface, ferrous salt is introduced into the configured electrolyte, and the Fe in the ferrous salt 2+ 1) The ions can reduce PbO2, greatly improving the removal efficiency of the failed active layer of lead dioxide on the surface of the anode; 2) The electrolyte configured in the present invention greatly reduces the concentration of nitric acid, and prolongs the service life of the workpiece on the basis of improving the working environment; 3) The several additives selected in the present invention are all cheap and easy to obtain, and will not damage the anode substrate, which not only greatly reduces the cost, but also improves the reuse efficiency of the anode substrate, and prolongs the service life of the anode in disguise.

[0017] In summary, the method for removing the failed lead dioxide coating on the surface of the anode of the present invention is simple to operate, economical and environmentally friendly, has friendly operating conditions, a short process, and is easy to industrialize. The treated anode surface is clean and has no failed active layer residue, and does not damage the base material. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 The present invention is a flow chart of removing the lead dioxide failure coating on the anode surface. DETAILED DESCRIPTION

[0019] The technical solution of the present invention is described below in conjunction with the accompanying drawings and embodiments.

[0020] Reference Figure 1 The method for electrochemically removing the lead dioxide failure coating on the anode surface provided by the present invention comprises the following steps:

[0021] S1. Pre-treat the anode with failed lead dioxide coating on the surface; the pre-treatment is specifically as follows: immerse the anode with failed lead dioxide coating on the surface in a deionized water pool, heat the deionized water to 50-60°C, and perform ultrasonic vibration for 1-2 hours; then use a high-pressure water gun to rinse for 5-10 minutes until the surface residue is rinsed clean and the failed electrode surface is exposed.

[0022] S2. Prepare an electrolyte: mix nitric acid, ferrous salt, citric acid monohydrate and deionized water to obtain an electrolyte;

[0023] The concentration of nitric acid in the electrolyte is 150 g / L, the concentration of ferrous salt is 10-15 g / L, and the concentration of citric acid monohydrate is 40 g / L; the ferrous salt is any one of FeC2O4 and FeCl2·4H2O.

[0024] S3. The anode with failed surface lead dioxide coating after S1 pretreatment is used as cathode to connect to the negative pole of power supply, and the insoluble anode is used as anode to connect to the positive pole of power supply, and the above plates are arranged in an electrolytic cell containing S2 electrolyte in a yin-yang-yin manner, and an external DC power supply is connected to power. When the power is turned on, the power supply adopts constant current mode, and the power supply current density is 200-300A / m 2 , remove the failed lead dioxide coating on the anode surface; until the power supply voltage shows 6V or above, the removal of the failed lead dioxide coating on the anode surface is completed.

[0025] The insoluble anode adopts a newly made titanium-based lead dioxide anode plate (produced by Xi'an Taijin New Energy Technology Co., Ltd.).

[0026] S4. After removing the failed lead dioxide coating on the surface, clean the anode with a high-pressure water gun until all the surface residues are rinsed away.

[0027] In the present invention, when electrochemically removing the lead dioxide failure coating on the anode surface, a ferrous salt is introduced into the configured electrolyte, and the Fe in the ferrous salt 2+ The ions can reduce PbO2, greatly improving the removal efficiency of the failed active layer of lead dioxide on the surface of the anode; the electrolyte configured in the present invention greatly reduces the concentration of nitric acid, and prolongs the service life of the workpiece on the basis of improving the working environment; the several additives selected in the present invention are all cheap and easy to obtain, and will not damage the anode substrate, which not only greatly reduces the cost, but also improves the reuse efficiency of the anode substrate, and prolongs the service life of the anode in disguise.

[0028] In summary, the method for removing the failed lead dioxide coating on the surface of the anode of the present invention is simple to operate, economical and environmentally friendly, has friendly operating conditions, a short process, and is easy to industrialize. The treated anode surface is clean and has no failed active layer residue, and does not damage the base material.

[0029] Example 1

[0030] A method for electrochemically removing a lead dioxide failure coating on an anode surface comprises the following steps:

[0031] S1. Pre-treat the anode with failed lead dioxide coating on the surface; the pre-treatment is specifically as follows: immerse the anode with failed lead dioxide coating on the surface in a deionized water pool, heat the deionized water to 55°C, and perform ultrasonic vibration for 1 hour; then use a high-pressure water gun to rinse for 5 minutes until the surface residue is rinsed clean and the failed electrode surface is exposed.

[0032] S2. Prepare an electrolyte: mix nitric acid, ferrous salt, citric acid monohydrate and deionized water to obtain an electrolyte; wherein the concentration of nitric acid in the electrolyte is 150 g / L, the ferrous salt is FeC2O4, the concentration is 10 g / L, and the concentration of citric acid monohydrate is 40 g / L;

[0033] S3. The anode with failed surface lead dioxide coating after S1 pretreatment is used as cathode to connect to the negative pole of power supply, and the newly made titanium-based lead dioxide anode plate is used as anode to connect to the positive pole of power supply, and the above plates are arranged in a cathode-anode-cathode manner in an electrolytic cell containing S2 electrolyte and energized. When energized, the power supply is turned on in constant current mode, and the power supply current density is 200A / m 2 , remove the failed lead dioxide coating on the anode surface; until the power supply voltage shows 6V or above, the removal of the failed lead dioxide coating on the anode surface is completed.

[0034] S4. After removing the failed lead dioxide coating on the surface, clean the anode with a high-pressure water gun until all the surface residues are rinsed away.

[0035] Example 2

[0036] A method for electrochemically removing a lead dioxide failure coating on an anode surface comprises the following steps:

[0037] S1. Pre-treat the anode with failed lead dioxide coating on the surface; the pre-treatment is specifically as follows: immerse the anode with failed lead dioxide coating on the surface in a deionized water pool, heat the deionized water to 50°C, and perform ultrasonic vibration for 2 hours; then use a high-pressure water gun to rinse for 8 minutes until the surface residue is rinsed clean and the failed electrode surface is exposed.

[0038] S2. Prepare an electrolyte: mix nitric acid, ferrous salt, citric acid monohydrate and deionized water to obtain an electrolyte; wherein the concentration of nitric acid in the electrolyte is 150 g / L, the concentration of ferrous salt is FeCl2·4H2O, the concentration is 15 g / L, and the concentration of citric acid monohydrate is 40 g / L;

[0039] S3. The anode with failed lead dioxide coating on the surface after S1 pretreatment is used as cathode to connect to the negative pole of the power supply, and the newly made titanium-based lead dioxide anode plate is used as anode to connect to the positive pole of the power supply. The above plates are arranged in a yin-yang-yin manner in an electrolytic cell containing S2 electrolyte and energized. When energized, the power supply is turned on in constant current mode, and the power supply current density is 260A / m 2 , remove the failed lead dioxide coating on the anode surface; until the power supply voltage shows 6V or above, the removal of the failed lead dioxide coating on the anode surface is completed.

[0040] S4. After removing the failed lead dioxide coating on the surface, clean the anode with a high-pressure water gun until all the surface residues are rinsed away.

[0041] Example 3

[0042] A method for electrochemically removing a lead dioxide failure coating on an anode surface comprises the following steps:

[0043] S1. Pre-treat the anode with failed lead dioxide coating on the surface; the pre-treatment is specifically as follows: immerse the anode with failed lead dioxide coating on the surface in a deionized water pool, heat the deionized water to 60°C, and perform ultrasonic vibration for 1.5 hours; then use a high-pressure water gun to rinse for 10 minutes until the surface residue is rinsed clean and the failed electrode surface is exposed.

[0044] S2. Prepare an electrolyte: mix nitric acid, ferrous salt, citric acid monohydrate and deionized water to obtain an electrolyte; wherein the concentration of nitric acid in the electrolyte is 150 g / L, the ferrous salt is FeC2O4, the concentration is 12 g / L, and the concentration of citric acid monohydrate is 40 g / L;

[0045] S3. The anode with failed surface lead dioxide coating after S1 pretreatment is used as cathode to connect to the negative pole of power supply, and the newly made titanium-based lead dioxide anode plate is used as anode to connect to the positive pole of power supply. The above plates are arranged in a yin-yang-yin manner in an electrolytic cell containing S2 electrolyte and energized. When energized, the power supply is turned on in constant current mode, and the power supply current density is 300A / m 2 , remove the failed lead dioxide coating on the anode surface; until the power supply voltage shows 6V or above, the removal of the failed lead dioxide coating on the anode surface is completed.

[0046] S4. After removing the failed lead dioxide coating on the surface, clean the anode with a high-pressure water gun until all the surface residues are rinsed away.

[0047] The above embodiments are only used to illustrate rather than limit the technical solutions of the present invention. Although the above embodiments describe the present invention in detail, relevant technical personnel in the field should understand that the present invention can be modified or equivalently replaced, but any modification and partial replacement that does not depart from the spirit and scope of the present invention should be included in the scope of the claims of the present invention.

Claims

1. A method for electrochemically removing lead dioxide failure coating on anode surface, characterized in that: The following steps are involved: S1. Pre-treating the anode with failed lead dioxide coating on the surface; S2. Prepare an electrolyte: mix nitric acid, ferrous salt, citric acid monohydrate and deionized water to obtain an electrolyte; The concentration of nitric acid in the electrolyte is 150 g / L, the concentration of ferrous salt is 10-15 g / L, and the concentration of citric acid monohydrate is 40 g / L; the ferrous salt is any one of FeC2O4 or FeCl2·4H2O; S3. The anode with the failed lead dioxide coating on the surface after S1 pretreatment is used as a cathode to connect to the negative electrode of the power supply, and an insoluble anode is used as an anode to connect to the positive electrode of the power supply, and the above-mentioned plates are arranged in an electrolytic cell containing S2 electrolyte in a yin-yang-yin manner and energized to remove the failed lead dioxide coating on the anode surface; S4. Clean the anode after removing the failed lead dioxide coating on the surface until all the surface residues are rinsed away.

2. The method for electrochemically removing lead dioxide failure coating on anode surface according to claim 1, characterized in that: The pretreatment in S1 is specifically as follows: immersing the anode with failed lead dioxide coating on the surface in a deionized water pool, heating the deionized water to 50-60° C., and simultaneously performing ultrasonic vibration for 1-2 hours; and then washing with a high-pressure water gun for 5-10 minutes until the surface residue is washed away and the failed electrode surface is exposed.

3. The method for electrochemically removing lead dioxide failure coating on anode surface according to claim 1, characterized in that: When S3 is powered on, the power supply is turned on in constant current mode, and the power supply current density is 200-300A / m 2 .

4. The method for electrochemically removing lead dioxide failure coating on anode surface according to claim 3, characterized in that: The sign that the removal of the failed lead dioxide coating on the anode surface in S3 is complete is: the power supply voltage is displayed as 6V or above.

5. The method for electrochemically removing lead dioxide failure coating on anode surface according to claim 1, characterized in that: The cleaning in S4 is performed by a high-pressure water gun.

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