Method for preparing aluminum alloy through electrolytic method

Abstract

The invention relates to the technical field of electrolytic aluminum alloys, and particularly discloses a method for preparing an aluminum alloy through an electrolytic process, aiming at the problem that the material performance and the use effect of an aluminum alloy product are directly influenced due to the fact that the dispersion degree of doped alloy elements in molten aluminum is low and the doping effect is poor. Extracting aluminum oxide; s2, doping electrolysis: mixing an aluminum oxide with molten chlorate, heating and melting, adding a doped alloy element and a surfactant, and electrifying for electrolysis to obtain an electrolytic aluminum alloy; and S3, forming treatment is conducted, specifically, the electrolytic aluminum alloy is machined, and an aluminum alloy product is obtained. By the adoption of the method for preparing the aluminum alloy through the electrolysis method, the aluminum alloy material doped with alloy elements can be prepared and dispersed more sufficiently and evenly, and the aluminum alloy material has more stable and long-acting material performance and use effect.

Description

Technical Field

[0001] The present invention relates to the technical field of electrolytic aluminum alloys, and in particular to a method for preparing aluminum alloys by electrolysis. Background Art

[0002] The electrolytic method used in industry to prepare aluminum alloys is mainly to electrolyze aluminum oxide and introduce other alloying elements to obtain aluminum alloy products with specific properties. When preparing aluminum alloys by electrolysis, the amount of added alloying elements can be adjusted during the electrolysis process to achieve personalized and customized processing of aluminum alloy performance, so as to meet the use requirements of aluminum alloys in different application scenarios and improve the application range of aluminum alloys. Electrolytic aluminum alloys can effectively extract high-purity aluminum from bauxite, which largely determines the material properties of aluminum alloys. The process reaction of electrolytic aluminum is relatively efficient, which can not only fully convert aluminum resources in raw materials such as bauxite into metallic aluminum, but also has a fast conversion rate and high production efficiency.

[0003] The process steps for preparing aluminum alloy by electrolysis mainly include: (1) separately preparing aluminum sources such as bauxite and other alloying elements for doping, extracting aluminum oxide from the bauxite and using it as a raw material for subsequent electrolysis; (2) adding aluminum oxide and molten salt to a pre-assembled electrolytic cell, heating them to melt them, adding doping alloying elements, and electrolyzing them to generate aluminum alloy materials; (3) removing the aluminum alloy material from the electrolytic cell, cooling and solidifying it, and processing it by extrusion and other machining to produce an aluminum alloy product with the desired product structure.

[0004] However, in the actual production process, it is found that when other alloying elements that need to be doped are added to the molten aluminum liquid, the degree of dispersion of these alloying elements in the aluminum liquid is low, that is, the doping effect is poor, which directly affects the material properties and use effects of aluminum alloy products. Summary of the invention

[0005] The purpose of the present invention is to solve the problem that the doped alloy elements in the aluminum liquid have a low degree of dispersion and a poor doping effect in the process of preparing aluminum alloy by traditional electrolysis, which directly affects the material properties and use effect of aluminum alloy products.

[0006] The present invention is achieved through the following technical solutions:

[0007] The present invention provides a method for preparing aluminum alloy by electrolysis, comprising the following steps:

[0008] S1 prepares raw materials: takes bauxite and extracts aluminum oxide;

[0009] S2 doping electrolysis: aluminum oxide is mixed with molten chloride salt, heated to melt, doping alloy elements and surfactants are added, and electrolysis is performed to obtain electrolytic aluminum alloy;

[0010] S3 forming process: machining the electrolytic aluminum alloy to obtain aluminum alloy products.

[0011] Preferably, the molten chloride salt comprises one or more of aluminum chloride or sodium chloride, and the amount of the molten chloride salt used accounts for 3.5-12% (w / w) of the total materials during electrolysis.

[0012] Preferably, the surfactant comprises one or more of saponin, lecithin, polylactic acid, polyvinyl alcohol or polyether ester, and the amount of the surfactant is 0.05-3% (w / w) based on the mass of the aluminum oxide.

[0013] Preferably, when the surfactant is saponin or polyether ester, the amount of saponin or polyether ester added is 0.1-1% (w / w) of the mass of aluminum oxide; when the surfactant is lecithin, the amount of lecithin added is 0.1-0.5% (w / w) of the mass of aluminum oxide; when the surfactant is polylactic acid or polyvinyl alcohol, the amount of polylactic acid or polyvinyl alcohol added is 0.5-3% (w / w) of the mass of aluminum oxide.

[0014] Preferably, in step S2, the heating temperature is 850-1000°C, and when the temperature exceeds 670°C, the doping alloy elements and surfactants begin to be added.

[0015] Preferably, in step S2, the current density of the energized water is 0.5-2A / cm2, and the electrolysis time is 6-12h.

[0016] Preferably, in step S1, the bauxite is crushed and ground, placed in a reactor, heated to 130-250°C, and the reaction pressure is controlled to be 0.4-0.6MPa to carry out the reaction; then the solid-liquid separation is carried out, the clear liquid is taken, cooled and hydrolyzed to precipitate aluminum hydroxide; and then placed at a high temperature of 1000-1100°C to react to form aluminum oxide.

[0017] The technical solution of the present invention has the following beneficial effects:

[0018] The method for preparing aluminum alloy by electrolysis provided by the present invention can effectively improve the deposition process of aluminum ions, increase the deposition rate and the uniformity of alloy components by controlling the time of adding doped alloy elements and the processing conditions before and after doping, and combining the effect of surfactants, so that the doped alloy elements can be more fully dispersed into the aluminum liquid, so that the aluminum alloy material finally prepared has more stable and long-lasting material properties and use effects. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention will be described clearly and completely below. Where specific conditions are not specified in the embodiments, they are carried out under conventional conditions or conditions recommended by the manufacturer; where the manufacturers of the instruments, equipment, reagents and raw materials used are not specified, they are all conventional products that can be purchased commercially.

[0020] The present invention provides a method for preparing aluminum alloy by electrolysis, comprising the following steps:

[0021] (1) Preparation of raw materials

[0022] Bauxite is taken as the main raw material for electrolytic aluminum, and is crushed and ground, and processed by the Bayer process to extract aluminum oxide. The extraction process is as follows:

[0023] The crushed and ground bauxite is added to a sodium hydroxide solution, mixed, added to a high-pressure reactor, heated to 130-250°C, and the pressure is controlled to be 0.4-0.6MPa to react so that the aluminum in the bauxite is dissolved into sodium aluminate; the mixed liquid after the reaction is solid-liquid separated to remove unreacted bauxite and undissolved impurities, and the filtered sodium aluminate clear liquid is cooled and hydrolyzed to precipitate aluminum hydroxide; the obtained aluminum hydroxide is placed at a high temperature of 1000-1100°C for reaction, evaporated and dehydrated to form aluminum oxide.

[0024] (2) Conducting electrolytic reaction

[0025] Aluminum oxide and molten chloride salt are added to the electrolytic cell and heated to 850-1000℃ to completely melt the aluminum oxide and molten chloride salt. When the temperature exceeds 670℃, doping alloy elements and surfactants are added and stirred evenly. Direct current is passed to carry out electrolysis reaction, and the current density is 0.5-2A / cm 2 The electrolysis time is 6-12h, and after the reaction, electrolytic aluminum alloy is deposited at the bottom of the electrolytic cell.

[0026] The molten chloride salt can be selected from aluminum chloride, sodium chloride or other metal chlorides, and the amount of the molten chloride salt accounts for 3.5-12% (w / w) of the total material during electrolysis;

[0027] The surfactant adopts a bio-based or degradable functional surfactant, which can be specifically selected from natural substances such as saponin, lecithin, or organic substances such as polylactic acid, polyvinyl alcohol, polyether ester, etc., and the amount of the surfactant used accounts for 0.05-3% (w / w) of the mass of aluminum oxide, so as to improve the deposition process of aluminum ions, increase the deposition rate and the uniformity of the alloy composition.

[0028] Specifically, when the surfactant is saponin or polyether ester, the amount of saponin or polyether ester added is 0.1-1% (w / w) of the mass of aluminum oxide; when the surfactant is lecithin, the amount of lecithin added is 0.1-0.5% (w / w) of the mass of aluminum oxide; when the surfactant is polylactic acid or polyvinyl alcohol, the amount of polylactic acid or polyvinyl alcohol added is 0.5-3% (w / w) of the mass of aluminum oxide.

[0029] (3) Molding process

[0030] The aluminum alloy deposited after electrolysis is taken out, cooled for 1-2 hours to solidify it, and then subjected to machining processes such as extrusion and forging to obtain an aluminum alloy product.

[0031] Example 1

[0032] Step 1: Take about 2kg of bauxite, crush it with a crusher, and grind it into bauxite fragments with a particle size not exceeding 5cm; put the bauxite fragments into a diluted 25% sodium hydroxide solution, stir evenly and add it to a high-pressure reactor, heat the reactor, control the temperature to 185°C, the pressure in the reactor to 0.5MPa, and react for 3.5h; output the reacted material, and perform solid-liquid separation, take the separated clear liquid, cool and hydrolyze it, and precipitate aluminum hydroxide; then place the aluminum hydroxide at 1050°C and heat it for 2h to obtain about 705g of aluminum oxide for standby use.

[0033] Step 2: Mix the aluminum oxide obtained above with 64g aluminum chloride, add it to the electrolytic cell, and heat it to 950°C at about 50°C / min. During this period, when the temperature exceeds 670°C, slowly add 7.5g copper powder and 25g magnesium powder at a rate of 6g / min. When the temperature reaches 950°C, add 3.55g saponin and stir well; then pass 1.5A / cm 2 The current is applied and the electrolysis is carried out for 10 hours. After the electrolysis reaction is completed, the electrolytic aluminum alloy deposited at the bottom of the electrolytic cell is collected.

[0034] Step 3: Cool the electrolytic aluminum alloy for 2 hours to solidify it into a shape, and then machine it into an aluminum alloy block product by forging.

[0035] According to GB / T 16474-2008 “Tensile Test Methods for Aluminum and Aluminum Alloys” and GB / T 3190-2017 “Chemical Analysis Methods for Aluminum and Aluminum Alloys”, the tensile properties of the aluminum alloy block product prepared above were measured to be 526 MPa and the hardness was 188 Hv.

[0036] Example 2

[0037] Step 1: Take about 2 kg of bauxite, crush it with a crusher, and grind it into bauxite fragments with a particle size not exceeding 5 cm; put the bauxite fragments into a diluted 25% sodium hydroxide solution, stir evenly and add it to a high-pressure reactor, heat the reactor, control the temperature to 185°C, the pressure in the reactor to 0.5 MPa, and react for 3.5 hours; output the reacted material, and perform solid-liquid separation, take the separated clear liquid, cool and hydrolyze it, and precipitate aluminum hydroxide; then place the aluminum hydroxide at 1050°C and heat it for 2 hours to obtain about 706.5g of aluminum oxide for standby use.

[0038] Step 2: Mix the aluminum oxide obtained above with 63.9g aluminum chloride, add it to the electrolytic cell, and heat it to 950°C at about 50°C / min. During this period, when the temperature exceeds 670°C, slowly add 7.5g copper powder and 25g magnesium powder at a rate of 6g / min. When the temperature reaches 950°C, add 1.45g lecithin and stir well; then pass 1.5A / cm 2 The current is applied and the electrolysis is carried out for 10 hours. After the electrolysis reaction is completed, the electrolytic aluminum alloy deposited at the bottom of the electrolytic cell is collected.

[0039] Step 3: Cool the electrolytic aluminum alloy for 2 hours to solidify it into a shape, and then machine it into an aluminum alloy block product by forging.

[0040] According to GB / T 16474-2008 “Tensile Test Methods for Aluminum and Aluminum Alloys” and GB / T 3190-2017 “Chemical Analysis Methods for Aluminum and Aluminum Alloys”, the tensile properties of the aluminum alloy block product prepared above were measured to be 521 MPa and the hardness was 190 Hv.

[0041] Example 3

[0042] Step 1: Take about 2kg of bauxite, crush it with a crusher, and grind it into bauxite fragments with a particle size not exceeding 5cm; put the bauxite fragments into a diluted 25% sodium hydroxide solution, stir evenly and add it to a high-pressure reactor, heat the reactor, control the temperature to 185°C, the pressure in the reactor to 0.5MPa, and react for 3.5h; output the reacted material, and perform solid-liquid separation, take the separated clear liquid, cool and hydrolyze it, and precipitate aluminum hydroxide; then place the aluminum hydroxide at 1050°C and heat it for 2h to obtain about 704g of aluminum oxide for standby use.

[0043] Step 2: Mix the aluminum oxide obtained above with 64.3g aluminum chloride, add it to the electrolytic cell, and heat it to 950°C at about 50°C / min. During this period, when the temperature exceeds 670°C, start to slowly add 7.5g copper powder and 25g magnesium powder at a rate of 6g / min. When the temperature reaches 950°C, add 7.05g polylactic acid and stir well; then pass 1.5A / cm 2 The current is applied and the electrolysis is carried out for 10 hours. After the electrolysis reaction is completed, the electrolytic aluminum alloy deposited at the bottom of the electrolytic cell is collected.

[0044] Step 3: Cool the electrolytic aluminum alloy for 2 hours to solidify it into a shape, and then machine it into an aluminum alloy block product by forging.

[0045] According to GB / T 16474-2008 “Tensile Test Methods for Aluminum and Aluminum Alloys” and GB / T 3190-2017 “Chemical Analysis Methods for Aluminum and Aluminum Alloys”, the tensile properties of the aluminum alloy block product prepared above were measured to be 525 MPa and the hardness was 191 Hv.

[0046] Example 4

[0047] Step 1: Take about 2kg of bauxite, crush it with a crusher, and grind it into bauxite fragments with a particle size not exceeding 5cm; put the bauxite fragments into a diluted 25% sodium hydroxide solution, stir evenly and add it to a high-pressure reactor, heat the reactor, control the temperature to 185°C, the pressure in the reactor to 0.5MPa, and react for 3.5h; output the reacted material, and perform solid-liquid separation, take the separated clear liquid, cool and hydrolyze it, and precipitate aluminum hydroxide; then place the aluminum hydroxide at 1050°C and heat it for 2h to obtain about 705g of aluminum oxide for standby use.

[0048] Step 2: Mix the aluminum oxide obtained above with 65g of sodium chloride, add it to the electrolytic cell, and heat it to 950°C at about 50°C / min. During this period, when the temperature exceeds 670°C, slowly add 30g of magnesium powder at a rate of 6g / min. When the temperature reaches 950°C, add 3.55g of saponin and stir well; then pass 1.5A / cm 2 The current is applied and the electrolysis is carried out for 10 hours. After the electrolysis reaction is completed, the electrolytic aluminum alloy deposited at the bottom of the electrolytic cell is collected.

[0049] Step 3: Cool the electrolytic aluminum alloy for 2 hours to solidify it into a shape, and then machine it into an aluminum alloy block product by forging.

[0050] According to GB / T 16474-2008 “Tensile Test Methods for Aluminum and Aluminum Alloys” and GB / T 3190-2017 “Chemical Analysis Methods for Aluminum and Aluminum Alloys”, the tensile properties of the aluminum alloy block product prepared above were measured to be 519 MPa and the hardness was 185 Hv.

[0051] Example 5

[0052] Step 1: Take about 2kg of bauxite, crush it with a crusher, and grind it into bauxite fragments with a particle size not exceeding 5cm; put the bauxite fragments into a diluted 25% sodium hydroxide solution, stir evenly and add it to a high-pressure reactor, heat the reactor, control the temperature to 185°C, the pressure in the reactor to 0.5MPa, and react for 3.5h; output the reacted material, and perform solid-liquid separation, take the separated clear liquid, cool and hydrolyze it, and precipitate aluminum hydroxide; then place the aluminum hydroxide at 1050°C and heat it for 2h to obtain about 705g of aluminum oxide for standby use.

[0053] Step 2: Mix the aluminum oxide obtained above with 64g aluminum chloride, add it to the electrolytic cell, and heat it to 900°C at about 50°C / min. During this period, when the temperature exceeds 750°C, slowly add 7.5g copper powder and 25g magnesium powder at a rate of 10g / min. When the temperature reaches 880°C, add 3.55g saponin and stir well; then pass 1.5A / cm 2 The current is applied and the electrolysis is carried out for 10 hours. After the electrolysis reaction is completed, the electrolytic aluminum alloy deposited at the bottom of the electrolytic cell is collected.

[0054] Step 3: Cool the electrolytic aluminum alloy for 2 hours to solidify it into a shape, and then machine it into an aluminum alloy block product by forging.

[0055] According to GB / T 16474-2008 “Tensile Test Methods for Aluminum and Aluminum Alloys” and GB / T 3190-2017 “Chemical Analysis Methods for Aluminum and Aluminum Alloys”, the tensile properties of the aluminum alloy block product prepared above were measured to be 518 MPa and the hardness was 181 Hv.

[0056] Example 6

[0057] Step 1: Take about 2kg of bauxite, crush it with a crusher, and grind it into bauxite fragments with a particle size not exceeding 5cm; put the bauxite fragments into a diluted 25% sodium hydroxide solution, stir evenly and add it to a high-pressure reactor, heat the reactor, control the temperature to 185°C, the pressure in the reactor to 0.5MPa, and react for 3.5h; output the reacted material, and perform solid-liquid separation, take the separated clear liquid, cool and hydrolyze it, and precipitate aluminum hydroxide; then place the aluminum hydroxide at 1050°C and heat it for 2h to obtain about 705g of aluminum oxide for standby use.

[0058] Step 2: Mix the aluminum oxide obtained above with 64g aluminum chloride, add it to the electrolytic cell, and heat it to 950°C at about 50°C / min. During this period, when the temperature exceeds 670°C, slowly add 7.5g copper powder and 25g magnesium powder at a rate of 6g / min. When the temperature reaches 950°C, add 3.55g saponin and stir well; then pass 2A / cm 2 The current was charged and the electrolysis was carried out for 8 hours. After the electrolysis reaction was completed, the electrolytic aluminum alloy deposited at the bottom of the electrolytic cell was collected.

[0059] Step 3: Cool the electrolytic aluminum alloy for 2 hours to solidify it into a shape, and then machine it into an aluminum alloy block product by forging.

[0060] According to GB / T 16474-2008 “Tensile Test Methods for Aluminum and Aluminum Alloys” and GB / T 3190-2017 “Chemical Analysis Methods for Aluminum and Aluminum Alloys”, the tensile properties of the aluminum alloy block product prepared above were measured to be 520 MPa and the hardness was 181 Hv.

[0061] Comparative Example 1

[0062] Step 1: Take about 2kg of bauxite, crush it with a crusher, and grind it into bauxite fragments with a particle size not exceeding 5cm; put the bauxite fragments into a diluted 25% sodium hydroxide solution, stir evenly and add it to a high-pressure reactor, heat the reactor, control the temperature to 185°C, the pressure in the reactor to 0.5MPa, and react for 3.5h; output the reacted material, and perform solid-liquid separation, take the separated clear liquid, cool and hydrolyze it, and precipitate aluminum hydroxide; then place the aluminum hydroxide at 1050°C and heat it for 2h to obtain about 705g of aluminum oxide for standby use.

[0063] Step 2: Mix the aluminum oxide obtained above with 64g aluminum chloride, add it to the electrolytic cell, heat it to 950℃ at about 50℃ / min; then pass 1.5A / cm 2 The current is applied and the electrolysis is carried out for 10 hours. After the electrolysis reaction is completed, the electrolytic aluminum alloy deposited at the bottom of the electrolytic cell is collected.

[0064] Step 3: Cool the electrolytic aluminum alloy for 2 hours to solidify it into a shape, and then machine it into an aluminum alloy block product by forging.

[0065] According to GB / T 16474-2008 “Tensile Test Methods for Aluminum and Aluminum Alloys” and GB / T 3190-2017 “Chemical Analysis Methods for Aluminum and Aluminum Alloys”, the tensile properties of the aluminum alloy block product prepared above were measured to be 503 MPa and the hardness was 167 Hv.

[0066] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing aluminum alloy by electrolysis, characterized in that: The following steps are involved: S1 prepares raw materials: takes bauxite and extracts aluminum oxide; S2 doping electrolysis: aluminum oxide is mixed with molten chloride salt, heated to melt, doping alloy elements and surfactants are added, and electrolysis is performed to obtain electrolytic aluminum alloy; S3 forming process: machining the electrolytic aluminum alloy to obtain aluminum alloy products.

2. The method for preparing aluminum alloy by electrolysis according to claim 1, characterized in that: The molten chloride salt comprises one or more of aluminum chloride or sodium chloride, and the amount of the molten chloride salt used accounts for 3.5-12% (w / w) of the total materials during electrolysis.

3. The method for preparing aluminum alloy by electrolysis according to claim 1, characterized in that: The surfactant includes one or more of saponin, lecithin, polylactic acid, polyvinyl alcohol or polyether ester, and the amount of the surfactant is 0.05-3% (w / w) of the mass of the aluminum oxide.

4. The method for preparing aluminum alloy by electrolysis according to claim 3, characterized in that: When the surfactant is saponin or polyether ester, the added amount of saponin or polyether ester is 0.1-1% (w / w) of the mass of aluminum oxide; When the surfactant is lecithin, the amount of lecithin added is 0.1-0.5% (w / w) of the mass of aluminum oxide; When the surfactant is polylactic acid or polyvinyl alcohol, the added amount of polylactic acid or polyvinyl alcohol is 0.5-3% (w / w) of the mass of aluminum oxide.

5. The method for preparing aluminum alloy by electrolysis according to claim 1, characterized in that: In step S2, the heating temperature is 850-1000°C, and when the temperature exceeds 670°C, doping alloy elements and surfactants are started to be added.

6. The method for preparing aluminum alloy by electrolysis according to claim 1, characterized in that: In step S2, the current density of the energized current is 0.5-2A / cm 2 , the electrolysis time is 6-12h.

7. The method for preparing aluminum alloy by electrolysis according to claim 1, characterized in that: In step S1, the bauxite is crushed and ground, placed in a reactor, heated to 130-250°C, and the reaction pressure is controlled to be 0.4-0.6MPa to react; then solid-liquid separation is performed, the clear liquid is taken, cooled and hydrolyzed, and aluminum hydroxide is precipitated; and then placed at a high temperature of 1000-1100°C to react to form aluminum oxide.