A method for the purification and packaging of magnesium ingots for the casting of aluminium alloys

Abstract

The application discloses a magnesium ingot cleaning treatment method and packaging method for aluminum alloy casting, which comprises the following steps: first, cleaning treatment is performed on the surface of the aluminum alloy casting magnesium ingot; second, the cleaned aluminum alloy casting magnesium ingot is washed with low-ion water; third, the washed aluminum alloy casting magnesium ingot is placed in a negative pressure environment for desorption drying treatment, and a treated magnesium ingot is prepared; and a heat-shrinkable film is sleeved on the outside of the cleaned aluminum alloy casting magnesium ingot, and heat-shrinkable packaging is performed through a hot air gun. The main function of the packaging is to minimize secondary moisture absorption, oxidation, friction pollution and external dust pollution during transportation and storage of the magnesium ingot after the cleaning treatment, so that the clean state can be maintained for a long time, and the risk of surface defects such as black lines, white lines, pitting and inclusions in the aluminum alloy anodization process can be reduced.

Description

Technical Field

[0001] This invention relates to the field of alloy smelting technology, specifically to a method for cleaning and packaging magnesium ingots used in aluminum alloy casting. Background Technology

[0002] Magnesium ingots are widely used in aluminum-magnesium alloys, aluminum alloy composition adjustment, battery casing materials, anodizing materials, and high-surface-quality aluminum plates, strips, and foils.

[0003] Currently, the industry's focus on magnesium ingot quality is mainly on magnesium content, metal impurity content, and chemical purity, while less attention is paid to the oxidation state of magnesium ingot surface and its impact on the cleanliness of aluminum melt.

[0004] Because magnesium has high chemical reactivity, its surface is prone to oxidation during production, transportation and storage: 2Mg + O2 → 2MgO. Traditional packaging methods usually use ordinary plastic packaging, woven bags or simple stretch film packaging, which only meet the transportation and basic moisture protection requirements, and do not control the problem of continuous oxidation on the surface of magnesium ingots.

[0005] The inventors discovered that after magnesium ingots are fed into the furnace, the oxide layer on the surface tends to float on the surface of the molten aluminum due to its low density, and undergoes an interfacial reaction with the alumina film on the surface of the molten aluminum. MgO + Al2O3 → MgAl2O4; a reddish-gray film-like substance may be formed during this reaction. The inventors speculate that this substance may contain magnesium aluminum spinel and oxide composite inclusions. The aforementioned composite film and inclusions are characterized by being difficult to dissolve, difficult to remove, and easily entangled in the melt, which can easily lead to problems such as black lines, white lines, pitting, surface streaks, and melt filter blockage during subsequent processing.

[0006] Currently, when the above-mentioned defects occur, the industry usually prioritizes the purity of magnesium ingots, refining processes, and filtration processes, while paying insufficient attention to the fact that "the oxide layer on the surface of magnesium ingots may itself be a hidden source of pollution," resulting in a certain problem of "emphasizing purity while neglecting surface condition."

[0007] Therefore, developing a magnesium ingot purification and packaging method that can reduce the oxidation activity of magnesium ingot surface and reduce the entry of surface oxide layer into aluminum melt is of great industrial significance for improving the cleanliness of high-end aluminum alloy melt and reducing the risk of surface defects. Summary of the Invention

[0008] To address the aforementioned technical problems, this invention provides a method for the purification and packaging of magnesium ingots used in aluminum alloy casting.

[0009] The objective of this invention can be achieved through the following technical solutions: A method for cleaning magnesium ingots used in aluminum alloy casting includes the following steps: The first step is to clean the surface of the magnesium ingots cast from aluminum alloy. The second step is to rinse the magnesium ingots cast from the cleaned aluminum alloy with low-ion water. Low-ion water is used for cleaning, and it is not required to meet the standard of completely deionized water. The main purpose is to reduce the residual soluble salts such as chloride ions and sodium ions in the water, and reduce the risk of subsequent moisture absorption, oxidation and impurities. The third step is to place the washed aluminum alloy cast magnesium ingot in a negative pressure environment for desorption and drying treatment to obtain the treated magnesium ingot; in order to reduce surface adsorbed water and microporous residual liquid. Furthermore, the first step of the purification process includes pickling, air drying, and baking, with a processing cycle of 24 hours.

[0010] Furthermore, the pickling process includes the following steps: Magnesium ingots cast from aluminum alloy are immersed in pickling solution and ultrasonically vibrated at room temperature for 5-15 minutes. The pickling solution is a citric acid solution with a mass fraction of 3-8%, and hexamethylenetetramine, a corrosion inhibitor, is added at a mass fraction of 0.5-1.5%. After pickling, the ingots are removed and rinsed with deionized water 2-3 times to remove residual acid from the surface. They are then placed in a ventilated place to air dry naturally for 2-4 hours, and then transferred to a constant temperature drying oven to dry at 60-80 ℃ for 2-4 hours to complete the pickling process.

[0011] Furthermore, when the concentration of magnesium ions in the pickling solution accumulates to more than 20 g / L, the solution needs to be replaced with a fresh one. The ultrasonic oscillation frequency is 40-60 kHz.

[0012] Furthermore, in the second step, the rinsing is performed 3-4 times, with each rinsing lasting 1-2 minutes.

[0013] Furthermore, in the third step, the desorption and drying temperature is controlled at 80-120℃ for 4-6 hours.

[0014] A method for packaging magnesium ingots cast from aluminum alloy after purification treatment includes the following steps: After purification treatment, the magnesium ingots cast from aluminum alloy are coated with heat-shrink film and then heat-shrink sealed using a hot air gun.

[0015] Furthermore, the heat-shrinkable film can also be replaced with an oxygen barrier film or a vacuum film.

[0016] The main purpose of encapsulation is to minimize secondary moisture absorption, oxidation, friction contamination, and external dust contamination during transportation and storage of magnesium ingots after the purification process, thereby maintaining a clean state for a longer period of time.

[0017] The beneficial effects of this invention are: 1. It can reduce the oxidation activity of magnesium ingot surface; 2. It can reduce the risk of non-metallic inclusions in molten aluminum; 3. It can improve the cleanliness of the melt and the stability of casting; 4. It can reduce defects such as black lines, white lines, pitting, and stripes in anodized products; 5. It can reduce problems such as melt filter clogging; 6. When the magnesium ingots prepared by this invention are used in battery casing materials, they can improve the surface quality of high-end plates, strips, foils, and battery casing materials. Detailed Implementation

[0018] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] Example 1: A method for cleaning magnesium ingots used in aluminum alloy casting, comprising the following steps: The first step is to clean the surface of the magnesium ingots cast from aluminum alloy. The second step is to rinse the magnesium ingots cast from the cleaned aluminum alloy with low-ion water. Low-ion water is used for cleaning, and it is not required to meet the standard of completely deionized water. The main purpose is to reduce the residual soluble salts such as chloride ions and sodium ions in the water, and reduce the risk of subsequent moisture absorption, oxidation and impurities. The third step is to place the washed aluminum alloy cast magnesium ingot in a negative pressure environment for desorption and drying treatment to obtain the treated magnesium ingot; in order to reduce surface adsorbed water and microporous residual liquid. The first step of the purification process includes pickling, air drying, and baking, with a processing cycle of 24 hours.

[0020] The pickling process includes the following steps: Magnesium ingots cast from aluminum alloy were immersed in pickling solution and ultrasonically vibrated for 5 minutes at room temperature. The pickling solution was a 3% citric acid solution with 0.5% hexamethylenetetramine as a corrosion inhibitor. After pickling, the ingots were removed and rinsed twice with deionized water to remove residual acid from the surface. They were then placed in a ventilated place to air dry naturally for 2 hours, and then transferred to a constant temperature drying oven to dry at 60 ℃ for 2 hours to complete the pickling process.

[0021] When the concentration of magnesium ions in the pickling solution exceeds 20 g / L, the solution needs to be replaced with a new one. The ultrasonic oscillation frequency is 40 kHz.

[0022] In the second step, the rinsing is performed 3 times, with each rinsing lasting 1 minute.

[0023] In the third step, the desorption and drying process is controlled at 80℃ for 4 hours.

[0024] A method for packaging magnesium ingots cast from aluminum alloy after purification treatment includes the following steps: After purification treatment, the magnesium ingots cast from aluminum alloy are coated with heat-shrink film and then heat-shrink sealed using a hot air gun.

[0025] The main purpose of encapsulation is to minimize secondary moisture absorption, oxidation, friction contamination, and external dust contamination during transportation and storage of magnesium ingots after the purification process, thereby maintaining a clean state for a longer period of time.

[0026] Example 2: A method for cleaning magnesium ingots used in aluminum alloy casting, comprising the following steps: The first step is to clean the surface of the magnesium ingots cast from aluminum alloy. The second step is to rinse the magnesium ingots cast from the cleaned aluminum alloy with low-ion water. Low-ion water is used for cleaning, and it is not required to meet the standard of completely deionized water. The main purpose is to reduce the residual soluble salts such as chloride ions and sodium ions in the water, and reduce the risk of subsequent moisture absorption, oxidation and impurities. The third step is to place the washed aluminum alloy cast magnesium ingot in a negative pressure environment for desorption and drying treatment to obtain the treated magnesium ingot; in order to reduce surface adsorbed water and microporous residual liquid. The first step of the purification process includes pickling, air drying, and baking, with a processing cycle of 24 hours.

[0027] The pickling process includes the following steps: Magnesium ingots cast from aluminum alloy were immersed in pickling solution and ultrasonically vibrated for 10 minutes at room temperature. The pickling solution was a 5% citric acid solution with 0.8% hexamethylenetetramine as a corrosion inhibitor. After pickling, the ingots were removed and rinsed twice with deionized water to remove residual acid from the surface. They were then placed in a ventilated place to air dry naturally for 2 hours, and then transferred to a constant temperature drying oven to dry at 70°C for 3 hours to complete the pickling process.

[0028] When the concentration of magnesium ions in the pickling solution exceeds 20 g / L, the solution needs to be replaced with a new one. The ultrasonic oscillation frequency is 50 kHz.

[0029] The second step involves rinsing three times, with each rinse lasting 1.5 minutes.

[0030] In the third step, the desorption and drying process is controlled at 90℃ for 5 hours.

[0031] A method for packaging magnesium ingots cast from aluminum alloy after purification treatment includes the following steps: After purification treatment, the magnesium ingots cast from aluminum alloy are coated with an oxygen barrier film and then heat-shrink sealed using a hot air gun.

[0032] The main purpose of encapsulation is to minimize secondary moisture absorption, oxidation, friction contamination, and external dust contamination during transportation and storage of magnesium ingots after the purification process, thereby maintaining a clean state for a longer period of time.

[0033] Example 3, a method for cleaning magnesium ingots used in aluminum alloy casting, includes the following steps: The first step is to clean the surface of the magnesium ingots cast from aluminum alloy. The second step is to rinse the magnesium ingots cast from the cleaned aluminum alloy with low-ion water. Low-ion water is used for cleaning, and it is not required to meet the standard of completely deionized water. The main purpose is to reduce the residual soluble salts such as chloride ions and sodium ions in the water, and reduce the risk of subsequent moisture absorption, oxidation and impurities. The third step is to place the washed aluminum alloy cast magnesium ingot in a negative pressure environment for desorption and drying treatment to obtain the treated magnesium ingot; in order to reduce surface adsorbed water and microporous residual liquid. The first step of the purification process includes pickling, air drying, and baking, with a processing cycle of 24 hours.

[0034] The pickling process includes the following steps: Magnesium ingots cast from aluminum alloy were immersed in pickling solution and ultrasonically vibrated for 12 minutes at room temperature. The pickling solution was a 6% citric acid solution with 1.2% hexamethylenetetramine as a corrosion inhibitor. After pickling, the ingots were removed and rinsed three times with deionized water to remove residual acid from the surface. They were then placed in a ventilated place to air dry naturally for 3 hours, and then transferred to a constant temperature drying oven to dry at 70°C for 4 hours to complete the pickling process.

[0035] When the concentration of magnesium ions in the pickling solution exceeds 20 g / L, the solution needs to be replaced with a new one. The ultrasonic oscillation frequency is 60 kHz.

[0036] In the second step, the rinsing is performed 4 times, with each rinse lasting 1 minute.

[0037] In the third step, the desorption and drying process is controlled at 110℃ for 6 hours.

[0038] A method for packaging magnesium ingots cast from aluminum alloy after purification treatment includes the following steps: After purification treatment, the magnesium ingots cast from aluminum alloy are coated with heat-shrink film and then heat-shrink sealed using a hot air gun.

[0039] The main purpose of encapsulation is to minimize secondary moisture absorption, oxidation, friction contamination, and external dust contamination during transportation and storage of magnesium ingots after the purification process, thereby maintaining a clean state for a longer period of time.

[0040] Example 4: A method for cleaning magnesium ingots used in aluminum alloy casting, comprising the following steps: The first step is to clean the surface of the magnesium ingots cast from aluminum alloy. The second step is to rinse the magnesium ingots cast from the cleaned aluminum alloy with low-ion water. Low-ion water is used for cleaning, and it is not required to meet the standard of completely deionized water. The main purpose is to reduce the residual soluble salts such as chloride ions and sodium ions in the water, and reduce the risk of subsequent moisture absorption, oxidation and impurities. The third step is to place the washed aluminum alloy cast magnesium ingot in a negative pressure environment for desorption and drying treatment to obtain the treated magnesium ingot; in order to reduce surface adsorbed water and microporous residual liquid. The first step of the purification process includes pickling, air drying, and baking, with a processing cycle of 24 hours.

[0041] The pickling process includes the following steps: Magnesium ingots cast from aluminum alloy are immersed in pickling solution and ultrasonically vibrated for 15 minutes at room temperature. The pickling solution is an 8% citric acid solution with 1.5% hexamethylenetetramine as a corrosion inhibitor. After pickling, the ingots are removed and rinsed three times with deionized water to remove residual acid. They are then placed in a ventilated place to air dry naturally for 2-4 hours, and then transferred to a constant temperature drying oven to dry at 80°C for 4 hours to complete the pickling process.

[0042] When the concentration of magnesium ions in the pickling solution exceeds 20 g / L, the solution needs to be replaced with a new one. The ultrasonic oscillation frequency is 60 kHz.

[0043] The second step involves rinsing four times, with each rinse lasting 2 minutes.

[0044] In the third step, the desorption and drying process is controlled at 120℃ for 6 hours.

[0045] A method for packaging magnesium ingots cast from aluminum alloy after purification treatment includes the following steps: After purification treatment, the magnesium ingots cast from aluminum alloy are coated with a vacuum film and then heat-shrink sealed using a hot air gun.

[0046] The main purpose of encapsulation is to minimize secondary moisture absorption, oxidation, friction contamination, and external dust contamination during transportation and storage of magnesium ingots after the purification process, thereby maintaining a clean state for a longer period of time.

[0047] The above description is merely an example and illustration of the concept of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described or use similar methods to replace them, as long as they do not deviate from the concept of the invention or exceed the scope defined in the claims, they should all fall within the protection scope of the present invention.

Claims

1. A method for purifying magnesium ingots used in aluminum alloy casting, characterized in that, Includes the following steps: The first step is to clean the surface of the magnesium ingots cast from aluminum alloy. The second step is to rinse the magnesium ingots cast from the cleaned aluminum alloy with low-ion water. The third step is to place the washed aluminum alloy cast magnesium ingots in a negative pressure environment for desorption and drying treatment to obtain the treated magnesium ingots.

2. The method for purifying magnesium ingots for aluminum alloy casting according to claim 1, characterized in that, The first step of the purification process includes pickling, air drying, and baking, with a processing cycle of 24 hours.

3. The method for purifying magnesium ingots for aluminum alloy casting according to claim 2, characterized in that, The pickling process includes the following steps: Magnesium ingots cast from aluminum alloy are immersed in pickling solution and ultrasonically vibrated at room temperature for 5-15 minutes. The pickling solution is a citric acid solution with a mass fraction of 3-8%, and hexamethylenetetramine, a corrosion inhibitor, is added at a mass fraction of 0.5-1.5%. After pickling, the ingots are removed and rinsed with deionized water 2-3 times to remove residual acid from the surface. They are then placed in a ventilated place to air dry naturally for 2-4 hours, and then transferred to a constant temperature drying oven to dry at 60-80 ℃ for 2-4 hours to complete the pickling process.

4. The method for purifying magnesium ingots for aluminum alloy casting according to claim 3, characterized in that, When the concentration of magnesium ions in the pickling solution exceeds 20 g / L, the solution needs to be replaced with a new one. The ultrasonic oscillation frequency should be 40-60 kHz.

5. The method for purifying magnesium ingots for aluminum alloy casting according to claim 1, characterized in that, In the second step, the rinsing is performed 3-4 times, with each rinse lasting 1-2 minutes.

6. The method for purifying magnesium ingots for aluminum alloy casting according to claim 1, characterized in that, In the third step, the desorption and drying temperature is controlled at 80-120℃ for 4-6 hours.

7. A method for packaging magnesium ingots cast from aluminum alloy after purification treatment as described in claim 1, characterized in that, Includes the following steps: After purification treatment, the magnesium ingots cast from aluminum alloy are coated with heat-shrink film and then heat-shrink sealed using a hot air gun.

8. The method for packaging magnesium ingots cast from aluminum alloy after purification treatment according to claim 7, characterized in that, Heat shrink film can also be replaced with oxygen barrier film or vacuum film.