Cleaning method of lithium-containing stainless steel filter

Abstract

The invention belongs to the technical field of lithium liquid filtration, and discloses a cleaning method of a lithium-containing stainless steel filter. The cleaning method of the lithium-containing stainless steel filter comprises the following steps that the lithium-containing stainless steel filter is sequentially subjected to oxidation treatment, water soaking treatment, first-time acid pickling treatment, first-time ultrasonic cleaning, second-time acid pickling treatment, second-time ultrasonic cleaning and drying treatment, and the clean filter is obtained. According to the cleaning method, the cleaning effect is thorough, various pollutants such as organic matter and metal impurities in the filter can be effectively removed, the filtering efficiency of the filter is improved, and the service life of the filter is prolonged; the cleaning process is simple and efficient, through multiple steps of air oxidation, water soaking, acid pickling, ultrasonic cleaning and the like, operation is easy and convenient, and the cleaning efficiency is high; the cleaning method is high in pertinence, optimization design is specially carried out according to the special situation of the lithium-containing stainless steel filter, and the cleaning effect is better; the cleaning cost is low, conventional chemical reagents and equipment are adopted, and the method is suitable for industrial large-scale application.

Description

Technical Field

[0001] This invention relates to the field of lithium liquid filtration technology, and in particular to a cleaning method for a lithium-containing stainless steel filter. Background Technology

[0002] During lithium electrolyte filtration, stainless steel filters gradually accumulate impurities, affecting filtration efficiency and quality. Current cleaning methods suffer from incomplete cleaning and low efficiency. Common cleaning methods include degreasing, high-pressure pure water cleaning, and acid cleaning; however, these methods are designed for pipelines or high-flow filters and cannot effectively remove minute impurities from stainless steel filters, resulting in unsatisfactory cleaning effects.

[0003] Furthermore, while some automated cleaning devices have been proposed in existing technologies, their cleaning processes still require further optimization. For example, a cleaning booster pump is used to extract the cleaning agent from the cleaning agent tank and then into the cleaning water tank. The cleaning solution enters the filter element through a manual valve at the filter element inlet, and under pressure, washes away the contaminants adhering to the filter element surface. However, this method still suffers from unsatisfactory cleaning results.

[0004] Regarding the issue of impurities gradually accumulating in stainless steel filters during use, affecting filtration efficiency and quality, several invention patents have been issued. Patent CN114082704A discloses a cleaning method for a high-efficiency filter element used for filtering carbon fiber raw materials. This method includes solvent boiling, ultrasonic cleaning with deionized water, ultrasonic cleaning with alkaline solution, ultrasonic cleaning with deionized water, compressed air drying, and baking. While this method can remove most impurities from the filter element surface, it cannot effectively remove oil stains and organic matter such as fingerprints, and the cleaning effect still needs improvement. Patent CN110220830A discloses a cleaning and testing method for aluminum-based stainless steel pleated filter elements. This method includes kerosene immersion, rinsing, bubble testing, ultrasonic coarse cleaning, ultrasonic fine cleaning, secondary bubble testing, and flow rate testing. While this method can clean aluminum-based stainless steel pleated filter elements, there is still room for optimization in the selection of cleaning methods and cleaning agents, and it cannot completely remove organic matter and metallic impurities from the filter element surface. In patent CN114082704A, the stainless steel filter cleaning technology mostly adopts mechanical methods such as backwashing and brush cleaning, and lacks a chemical treatment step for lithium contaminants.

[0005] Therefore, it is of great significance to develop a cleaning method for lithium-containing stainless steel filters that can effectively remove impurities from stainless steel filters, improve filter efficiency and service life, and is simple to operate, low in cost, and suitable for large-scale industrial applications. Summary of the Invention

[0006] The purpose of this invention is to provide a cleaning method for lithium-containing stainless steel filters, thereby solving the problems of incomplete cleaning effect and inability to effectively remove minute impurities, especially organic and metallic impurities, from stainless steel filters in the existing technology.

[0007] To achieve the above-mentioned objectives, the present invention provides the following technical solution: This invention provides a cleaning method for a lithium-containing stainless steel filter, comprising the following steps: The lithium-containing stainless steel filter is subjected to oxidation treatment, water soaking treatment, first acid washing treatment, first ultrasonic cleaning treatment, second acid washing treatment, second ultrasonic cleaning treatment and drying treatment in sequence to obtain a clean filter.

[0008] Preferably, in the oxidation process, the gas introduced is air, the oxidation temperature is 80~120℃, and the oxidation time is 1~3h.

[0009] Preferably, in the soaking treatment, the water temperature is 40~60℃ and the soaking time is 2~4h.

[0010] Preferably, in the first and second pickling treatments, the pickling reagent is a nitric acid solution, the concentration of the nitric acid solution is 1-5%, and the pickling time is 0.5-2 hours.

[0011] Preferably, in the first and second ultrasonic cleaning, the ultrasonic frequency is independently 10~40kHz, and the ultrasonic cleaning time is independently 10~30min.

[0012] Preferably, in the drying process, the drying temperature is 60~100℃ and the drying time is 1~3h.

[0013] As can be seen from the above technical solution, compared with the prior art, the present invention has the following beneficial effects: This invention is specifically designed to address the characteristics of pollutants in lithium-containing environments by converting surface lithium residues into easily treatable compounds through air oxidation. The cleaning method described in this invention provides a thorough cleaning effect, effectively removing various contaminants such as organic matter and metallic impurities from the filter, thereby improving the filter's filtration efficiency and service life. The cleaning process is simple and efficient, involving multiple steps such as air oxidation, soaking in water, acid washing, and ultrasonic cleaning. It is easy to operate and highly efficient. The cleaning method is highly targeted, specifically optimized for the special conditions of lithium-containing stainless steel filters, resulting in better cleaning effects. The cleaning cost is low, using conventional chemical reagents and equipment, requiring no special devices, and is suitable for large-scale industrial applications. Attached Figure Description

[0014] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0015] Figure 1 This is a schematic flowchart of the cleaning method for the lithium-containing stainless steel filter of the present invention. Detailed Implementation

[0016] This invention provides a cleaning method for a lithium-containing stainless steel filter, comprising the following steps: The lithium-containing stainless steel filter is subjected to oxidation treatment, water soaking treatment, first acid washing treatment, first ultrasonic cleaning treatment, second acid washing treatment, second ultrasonic cleaning treatment and drying treatment in sequence to obtain a clean filter.

[0017] In this invention, the gas introduced during the oxidation treatment is preferably air, the temperature of the oxidation treatment is preferably 80~120℃, more preferably 90~110℃, more preferably 100~105℃, and the time of the oxidation treatment is preferably 1~3h, more preferably 1.5~2.5h, and more preferably 2h.

[0018] In this invention, the oxidation treatment involves placing a lithium-containing stainless steel filter in an air oxidation device to oxidize the organic matter and some metal impurities on the filter surface.

[0019] In this invention, the water temperature during the soaking treatment is preferably 40~60℃, more preferably 45~55℃, and even more preferably 48~50℃. The soaking time is preferably 2~4h, more preferably 2.5~3.5h, and even more preferably 3h.

[0020] In this invention, the purpose of the soaking treatment is to dissolve residual impurities.

[0021] In this invention, in the first pickling treatment and the second pickling treatment, the pickling reagent is preferably a nitric acid solution, the concentration of the nitric acid solution is preferably 1~5%, more preferably 2~4%, and even more preferably 3%, and the pickling time is preferably 0.5~2h, more preferably 1~1.5h.

[0022] In this invention, the purpose of the first pickling treatment is to remove the oxides remaining after the oxidation treatment; the purpose of the second pickling treatment is to further remove the remaining impurities.

[0023] In this invention, during the first and second ultrasonic cleaning, the ultrasonic frequency is preferably 10-40 kHz, more preferably 15-35 kHz, and even more preferably 20-30 kHz. The ultrasonic cleaning time is preferably 10-30 min, more preferably 15-25 min, and even more preferably 20-22 min.

[0024] In this invention, the purpose of the first ultrasonic cleaning is to remove residual acid and impurities; the purpose of the second ultrasonic cleaning is to ensure that the filter surface is clean.

[0025] In this invention, the drying temperature is preferably 60~100℃, more preferably 70~90℃, and even more preferably 80~85℃, and the drying time is preferably 1~3h, more preferably 1.5~2.5h, and even more preferably 2h.

[0026] This invention achieves a synergistic effect through a specific combination of parameters such as temperature, acid concentration, and ultrasonic frequency, which can effectively remove the special contaminant combination generated during lithium electrolysis.

[0027] This invention combines chemical cleaning (acid washing) and physical cleaning (ultrasonic cleaning) mechanisms to provide a complete solution to the problem of mixed contamination of organic matter, metal impurities and lithium compounds in filters unique to the lithium battery industry.

[0028] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0029] Example 1

[0030] The lithium-containing stainless steel filter was placed in an air oxidation device, air was introduced, and it was oxidized at 100°C for 2 hours. After the oxidation treatment was completed, the filter was placed in deionized water and soaked at 50°C for 3 hours. Then, the filter was soaked in a 3wt% nitric acid solution for 1 hour. After removing the filter, it was ultrasonically cleaned in deionized water at a frequency of 25kHz for 15 minutes. Then, the filter was soaked in a 3wt% nitric acid solution for 1 hour. After removing the filter, it was ultrasonically cleaned in deionized water at a frequency of 25kHz for 15 minutes. Finally, the treated filter was dried at 80°C for 2 hours to obtain a clean filter that can be reused.

[0031] Example 2

[0032] The lithium-containing stainless steel filter was placed in an air oxidation device, air was introduced, and it was oxidized at 120°C for 1 hour. After the oxidation treatment was completed, the filter was placed in deionized water and soaked at 60°C for 2 hours. Then, the filter was placed in a 5wt% nitric acid solution and soaked for 0.5 hours. After removing the filter, it was ultrasonically cleaned in deionized water at a frequency of 40kHz for 10 minutes. Then, the filter was soaked in a 5wt% nitric acid solution for 0.5 hours. After removing the filter, it was ultrasonically cleaned in deionized water at a frequency of 40kHz for 10 minutes. Finally, the treated filter was dried at 100°C for 1 hour to obtain a clean filter that could be reused.

[0033] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A cleaning method for a lithium-containing stainless steel filter, characterized in that, Includes the following steps: The lithium-containing stainless steel filter is subjected to oxidation treatment, water soaking treatment, first acid washing treatment, first ultrasonic cleaning treatment, second acid washing treatment, second ultrasonic cleaning treatment and drying treatment in sequence to obtain a clean filter.

2. The cleaning method for a lithium-containing stainless steel filter according to claim 1, characterized in that, In the oxidation process, the gas introduced is air, the oxidation temperature is 80~120℃, and the oxidation time is 1~3h.

3. The cleaning method for a lithium-containing stainless steel filter according to claim 2, characterized in that, During the soaking treatment, the water temperature is 40~60℃, and the soaking time is 2~4 hours.

4. A cleaning method for a lithium-containing stainless steel filter according to claim 2 or 3, characterized in that, In the first and second pickling treatments, the pickling reagent is nitric acid solution, the concentration of which is 1-5%, and the pickling time is 0.5-2 hours.

5. A cleaning method for a lithium-containing stainless steel filter according to claim 4, characterized in that, In the first and second ultrasonic cleaning processes, the ultrasonic frequency is independently 10~40kHz, and the ultrasonic cleaning time is independently 10~30min.

6. A cleaning method for a lithium-containing stainless steel filter according to claim 2 or 5, characterized in that, In the drying process, the drying temperature is 60~100℃ and the drying time is 1~3h.

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