Method for rapidly removing failed coating on surface of titanium anode plate

Abstract

The invention relates to the technical field of anode plate surface treatment, in particular to a method for quickly removing an invalid coating on the surface of a titanium anode plate, which comprises the following steps of: removing a noble metal coating on the surface of the titanium anode plate by adopting the processes of removing surface dirt, treating by a buffer oxide etching agent, removing residual chemical reagents on the surface of the titanium anode plate and the like. The titanium anode plate can be efficiently and repeatedly used, impurities are not introduced, and then the follow-up precious metal recovery efficiency is improved.

Description

Technical Field

[0001] This invention relates to the field of anode plate surface treatment technology, and specifically to a method for rapidly removing failed coatings from the surface of titanium anode plates. Background Technology

[0002] Titanium anode plates (such as DSA, Dimensionally Stable Anode) possess significant advantages in the electrochemical industry due to their unique material properties and structural design, and are widely used in electrolysis, electroplating, wastewater treatment, and other fields. With their high stability, efficient catalysis, long lifespan, environmental friendliness, and design flexibility, they have become a core component of modern electrochemical industry. Although the initial cost is relatively high, their comprehensive economic benefits and sustainability advantages have led to their gradual replacement of traditional anodes in high-end industrial fields, making them a key material for the upgrading of electrolysis technology.

[0003] However, the noble metal oxide coating (such as IrO2 and RuO2) on the surface of titanium anodes can lead to reduced current efficiency, increased cell voltage, and decreased selectivity of the oxygen / chlorine evolution reaction during long-term electrolysis due to electrochemical corrosion, physical peeling, and passivation layer formation, ultimately causing titanium anode plate failure. Removing the coating from the surface of titanium anode plates is a key step in extending anode life, reducing production costs, and improving electrolysis efficiency. Especially given the scarcity of precious metal resources, coating regeneration technology is of great significance to sustainable industrial development.

[0004] Currently, methods for removing failed coatings include molten salt method, acid etching method, mechanical polishing method, and electrochemical stripping method. Molten salt method results in coatings with high impurity content and low iridium content; acid etching method causes severe acid mist and a harsh operating environment; mechanical polishing method results in uneven surface treatment and limited processing capacity; electrochemical stripping method is energy-intensive and costly.

[0005] Therefore, developing a method for rapidly removing the failed coating from the surface of titanium anode plates is of great significance for improving coating stripping efficiency, precious metal recovery efficiency, and reducing the production cost of titanium anodes. Summary of the Invention

[0006] To address the aforementioned problems, the present invention aims to provide a method for rapidly removing the failed coating from the surface of a titanium anode plate. This method removes the precious metal coating from the surface of the titanium anode plate through a process of removing surface dirt, buffering oxide etchant treatment, and removing residual chemical reagents. This simplifies the removal process of the failed coating on the titanium anode surface, resulting in high removal efficiency, minimal substrate corrosion, no loss of precious metals, and low consumption of auxiliary materials. It significantly improves the reusability of the titanium anode plate and the subsequent precious metal recovery efficiency.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] A method for rapidly removing failed coatings from the surface of a titanium anode plate includes the following steps:

[0009] Step 1, Remove surface dirt: Immerse the titanium anode plate to be treated in a descaling agent until the precious metal coating is exposed, then remove and clean it;

[0010] The descaling agent is a 5%-10% EDTA disodium salt solution;

[0011] Step 2, etching treatment: Place the titanium anode plate treated in Step 1 into a buffer oxide etchant for treatment until the surface noble metal coating is completely removed.

[0012] The buffer oxide etchant is prepared from hydrofluoric acid at a concentration of 5-10% and ammonium fluoride at a concentration of 2.5%-20%.

[0013] Step 3: Remove residual chemical reagents from the surface of the titanium anode plate.

[0014] Preferably, in step 1, the treatment temperature of the descaling agent is 25-70℃, and the soaking time is 10-60 minutes.

[0015] Preferably, in step 2, the etching agent treatment time is 5-30 minutes, the treatment temperature is 25-50°C, and the treatment is performed 1-3 times.

[0016] Preferably, in step 3, the method for removing residual chemical reagents from the surface of the titanium anode plate is: rinsing with a high-pressure water gun, ultrasonic treatment, or brushing.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0018] 1. This invention uses disodium EDTA solution as a descaling agent, which efficiently complexes lead ions. EDTA and Pb 2 It forms a stable water-soluble complex, which is suitable for stubborn scale and can effectively remove scale adhering to the surface of titanium anode plates.

[0019] 2. This invention controls the corrosion rate of hydrofluoric acid on the substrate by introducing ammonium fluoride, making the coating removal rate controllable and greatly reducing the amount of corrosion on the titanium anode plate.

[0020] 3. This invention has a short reaction time and high processing efficiency, and can be applied to the removal of coatings from different precious metal coatings and different substrates.

[0021] 4. The precious metal coating collected by this invention has a high grade, does not introduce other impurities, and has almost no loss of precious metals, which significantly improves the efficiency and yield of subsequent precious metal recovery.

[0022] In summary, this invention removes the precious metal coating on the surface of a titanium anode plate through a process of removing surface dirt, buffering oxide etchant treatment, and removing residual chemical reagents. This simplifies the removal process of the failed coating on the titanium anode surface, resulting in high removal efficiency, minimal substrate corrosion, no loss of precious metals, and low consumption of auxiliary materials. It significantly improves the reusability of the titanium anode plate and the subsequent precious metal recovery efficiency. Attached Figure Description

[0023] Figure 1 This is a flowchart illustrating the rapid removal of failed coatings from the surface of a titanium anode plate according to the present invention. Detailed Implementation

[0024] The following examples are used to illustrate the present invention, but are not intended to limit the scope of the invention. Unless otherwise specified, the reagents used are conventional commercially available reagents or prepared according to existing technology; unless otherwise specified, the operating methods used are conventional operations in the art.

[0025] The present invention provides a method for rapidly removing failed coatings from the surface of titanium anode plates, such as... Figure 1 As shown, it includes the following steps:

[0026] Step 1, Remove surface dirt: Immerse the titanium anode plate to be treated in a 5-10% EDTA disodium salt solution for 10-60 minutes at a temperature of 25-70°C until the noble metal coating is exposed, then remove and clean.

[0027] Step 2, etching treatment: Place the titanium anode plate treated in Step 1 in a buffer oxide etchant prepared with 5-10% hydrofluoric acid and 2.5%-20% ammonium fluoride for 5-30 minutes at a temperature of 25-50℃. Repeat the treatment 1-3 times depending on the surface coating removal effect until the precious metal coating on the surface is completely removed.

[0028] Step 3, Remove residual chemical reagents: Use a high-pressure water gun, ultrasound or brush to treat the titanium anode plate from which the coating of Step 2 has been completely removed to remove the chemical reagents adhering to the surface.

[0029] Example 1

[0030] A method for rapidly removing failed coatings from the surface of a titanium anode plate includes the following steps:

[0031] Step 1: Immerse a 20cm*20cm titanium anode plate with failed surface coating in a 5% EDTA disodium salt solution at 25°C for 60 minutes, then remove and clean it.

[0032] Step 2: Immerse the titanium anode plate treated in Step 1 in 5% HF + 10% ammonium fluoride and treat it at 25°C for 30 min. Repeat this treatment once.

[0033] Step 3: Sonicate the titanium anode plate from which the coating from Step 2 has been completely removed for 5 minutes to remove the chemical reagents adhering to the surface, thus obtaining a recyclable titanium anode.

[0034] Example 2

[0035] A method for rapidly removing failed coatings from the surface of a titanium anode plate includes the following steps:

[0036] Step 1: Immerse the 20cm*20cm titanium anode plate with failed surface coating in a 10% EDTA disodium salt solution and treat it at 70℃ for 10 minutes, then remove and clean it.

[0037] Step 2: Immerse the titanium anode plate treated in Step 1 in 10% HF + 20% ammonium fluoride and treat it at 50°C for 5 minutes. Repeat the treatment 3 times.

[0038] Step 3: Rinse the titanium anode plate after the coating of Step 2 has been completely removed with a high-pressure water gun to remove the chemical reagents adhering to the surface, and obtain a recyclable titanium anode.

[0039] Example 3

[0040] A method for rapidly removing failed coatings from the surface of a titanium anode plate includes the following steps:

[0041] Step 1: Immerse a 20cm*20cm titanium anode plate with failed surface coating in a 7% EDTA disodium salt solution at 50°C for 30 minutes, then remove and rinse.

[0042] Step 2: Immerse the titanium anode plate treated in Step 1 in 5% HF + 20% ammonium fluoride and treat it at 50°C for 20 min. Repeat the treatment twice.

[0043] Step 3: Brush the titanium anode plate from which the coating from Step 2 has been completely removed with a brush to remove the chemical reagents adhering to the surface, thus obtaining a recyclable titanium anode.

[0044] Example 4

[0045] A method for rapidly removing failed coatings from the surface of a titanium anode plate includes the following steps:

[0046] Step 1: Immerse a 20cm*20cm titanium anode plate with failed surface coating in an 8% EDTA disodium salt solution and treat it at 40℃ for 25 minutes, then remove and rinse.

[0047] Step 2: Immerse the titanium anode plate treated in Step 1 in 5% HF + 2.5% ammonium fluoride and treat it at 25°C for 10 min. Repeat the treatment twice.

[0048] Step 3: Ultrasonically treat the titanium anode plate from which the coating from Step 2 has been completely removed for 10 minutes to remove the chemical reagents adhering to the surface, thus obtaining a recyclable titanium anode.

[0049] Comparative Example

[0050] A 20cm*20cm titanium anode plate with a failed surface coating was immersed in 10% sodium hydroxide solution at 50°C for 30 minutes. After rinsing, some scale remained on the surface. The treatment continued for another 30 minutes until the scale was removed. The titanium anode plate with the scale removed was then immersed in 10% HF solution at room temperature for 10 minutes. The reaction was violent, producing a large number of bubbles and turning the solution black. The titanium anode plate was then removed, and the surface corrosion was uneven, with some coating residue remaining. The treatment was repeated 5 times until the surface coating was completely removed, but the titanium anode plate was severely corroded. The titanium anode plate with the coating removed was rinsed and dried. The weight loss of the titanium anode plate during the reaction process was calculated to be 60%.

[0051] In summary, comparing the operational procedures of Examples 1-4 with the comparative examples, it can be seen that Examples 1-4 of the present invention, through the strong chelating effect of disodium EDTA salt, rapidly descale the titanium anode plate during the removal of scale, achieving good removal effect and high efficiency. Examples 1-4, in removing the failed coating from the titanium anode plate surface, introduce ammonium fluoride to inhibit the reaction rate between HF and the titanium anode, ensuring uniform coating removal with less than 5% substrate loss and no acid mist generation, resulting in a relatively environmentally friendly operating environment. The present invention simplifies the removal process of failed coatings on the titanium anode surface, achieving high removal efficiency, minimal substrate corrosion, no loss of precious metals, and low auxiliary material consumption, significantly improving the reusability of titanium anode plates and the subsequent precious metal recovery efficiency.

Claims

1. A method for rapidly removing failed coatings from the surface of a titanium anode plate, characterized in that, Includes the following steps: Step 1, Remove surface dirt: Immerse the titanium anode plate to be treated in a descaling agent until the precious metal coating is exposed, then remove and clean it; The descaling agent is a 5%-10% EDTA disodium salt solution; Step 2, etching treatment: Place the titanium anode plate treated in Step 1 into a buffer oxide etchant for treatment until the surface noble metal coating is completely removed. The buffer oxide etchant is prepared from hydrofluoric acid at a concentration of 5-10% and ammonium fluoride at a concentration of 2.5%-20%. Step 3: Remove residual chemical reagents from the surface of the titanium anode plate.

2. The method for rapidly removing the failed coating from the surface of a titanium anode plate according to claim 1, characterized in that, In step 1, the treatment temperature of the descaling agent is 25-70℃, and the soaking time is 10-60 minutes.

3. The method for rapidly removing the failed coating from the surface of a titanium anode plate according to claim 1, characterized in that, In step 2, the etching agent treatment time is 5-30 minutes, the treatment temperature is 25-50℃, and the treatment is performed 1-3 times.

4. The method for rapidly removing the failed coating from the surface of a titanium anode plate according to claim 1, characterized in that, In step 3, the method for removing residual chemical reagents from the surface of the titanium anode plate is: rinsing with a high-pressure water gun, ultrasonic treatment, or brushing.

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