Anode alloy for producing refined aluminum through three-layer liquid electrolysis method and preparation method of anode alloy

Abstract

The invention belongs to the technical field of refined aluminum production, and particularly relates to an anode alloy for producing refined aluminum through a three-layer liquid electrolysis method and a preparation method of the anode alloy. The anode alloy for producing the refined aluminum through the three-layer liquid electrolysis method comprises the following element components in percentage by mass: 38-40% of copper and 60-62% of aluminum, the copper and the aluminum are reasonably matched, the primary crystal temperature is low, the conductivity and the current efficiency are high, layering with electrolyte is facilitated, the phenomena of floating and caking of the alloy are effectively avoided, the electricity unit consumption of refined aluminum liquid is reduced, and the quality of the refined aluminum is improved.

Description

Technical Field

[0001] This invention belongs to the field of refined aluminum production technology, specifically relating to an anode alloy for producing refined aluminum by a three-layer liquid electrolysis method and its preparation method. Background Technology

[0002] Refined aluminum production typically employs a three-layer electrolysis method, with the bottom layer of the production tank being the anode alloy. Currently, copper-aluminum alloys are generally used as the anode alloy. Ideally, the anode alloy should be completely miscible with aluminum at high temperatures, have a melting point lower than the electrolyte, a density greater than the electrolyte, and be able to separate well with the electrolyte. However, in actual production, unreasonable copper-aluminum formulations can lead to low current efficiency, alloy floating, and alloy agglomeration, thus affecting the quality of refined aluminum and production efficiency. When the copper ratio is low, the alloy density decreases, causing the alloy to float and affecting the quality grade of the upper layer of refined aluminum. When the copper ratio is high, on the one hand, the increased copper density allows some copper to participate in electrochemical reactions, causing quality issues; on the other hand, the presence of iron-silicon impurities in the alloy can form complexes (Al2FeSi5, FeSiAl5), weakening the alloy's flowability and conductivity, thus affecting refined aluminum production, and also causing alloy agglomeration. These factors all impact the process control, stability, and sustainability of the three-layer electrolysis method for refining aluminum, as well as the quality of the refined aluminum product. Summary of the Invention

[0003] In view of this, the purpose of this invention is to provide an anode alloy for producing refined aluminum by a three-layer liquid electrolysis method and the preparation method thereof. The anode alloy for producing refined aluminum by the three-layer liquid electrolysis method provided by this invention has a low initial crystallization temperature, high conductivity and current efficiency, which is conducive to the separation of the alloy with the electrolyte, effectively avoids the phenomenon of alloy floating and agglomeration, reduces the unit consumption of refined aluminum liquid electrolysis, and improves the quality of refined aluminum.

[0004] To achieve the above objectives, the present invention provides the following technical solution:

[0005] This invention provides an anode alloy for producing refined aluminum using a three-layer liquid electrolysis method, comprising the following elemental components by mass percentage:

[0006] Copper: 38-40%, Aluminum: 60-62%.

[0007] Preferably, the primary crystallization temperature of the anode alloy for producing refined aluminum using the three-layer liquid electrolysis method is 547–565℃, and the density is 3.22–3.28 g / cm³. 3 Its conductivity is 1.30–1.34 A / Ω·cm, and its current efficiency is 99.97–100%.

[0008] This invention also provides a method for preparing anode alloys for producing refined aluminum using the three-layer liquid electrolysis method described in the above technical solution, comprising the following steps:

[0009] After electrolytic copper and electrolytic aluminum are smelted, the resulting melt is subjected to primary purification, slag removal, and secondary purification in sequence to obtain an anode alloy for producing refined aluminum by the three-layer liquid electrolysis method.

[0010] Preferably, the electrolytic copper contains ≥99.95% copper by mass.

[0011] Preferably, the mass percentage of aluminum in the electrolytic aluminum is ≥99.8%.

[0012] Preferably, the melting process includes: first heating from room temperature to 660°C, and then second heating from 660°C to 750°C.

[0013] Preferably, the smelting is carried out in a refined aluminum bath; the current in the refined aluminum bath is 90-100kA and the voltage is 4.0-4.5V.

[0014] Preferably, the second heating time is 4 to 5 hours.

[0015] Preferably, the first purification process includes: a third temperature increase from 750°C to 780°C; the third temperature increase takes 3 to 4 hours.

[0016] Preferably, the temperature of the secondary purification is 780-790℃, and the heat preservation time is 2-4 hours.

[0017] This invention provides an anode alloy for producing refined aluminum using a three-layer liquid electrolysis method, comprising the following elemental composition by mass percentage: copper: 38-40%, aluminum: 60-62%. The copper-to-aluminum ratio in the anode alloy provided by this invention is reasonable, with a relatively low primary crystallization temperature (547-565℃), and relatively high electrical conductivity (1.30-1.34 A / Ω·cm) and current efficiency (99.97-100%), more closely meeting the process requirements for refining refined aluminum using the three-layer liquid electrolysis method. The alloy density is 3.22-3.28 g / cm³. 3 This process facilitates the separation of the anode alloy with the electrolyte, resulting in a smoother alloy that is less prone to floating. The copper concentration is also beneficial for the electrochemical reaction of aluminum within the alloy. The production temperature (751–762℃) is optimal for the three-layer electrolytic refining of aluminum, preventing the precipitation of alloy impurities and ensuring a stable and continuous production process. This reduces the energy consumption per unit volume of the refined aluminum solution and improves the quality of the refined aluminum. Furthermore, the anode alloy used in this three-layer electrolytic method facilitates the control of the three-layer aluminum production process and allows for automated alloy stirring in the feed chamber, avoiding contamination caused by manual stirring. Detailed Implementation

[0018] This invention provides an anode alloy for producing refined aluminum using a three-layer liquid electrolysis method, comprising the following elemental components by mass percentage:

[0019] Copper: 38-40%, Aluminum: 60-62%.

[0020] The elemental composition of the anode alloy for producing refined aluminum by the three-layer liquid electrolysis method provided by the present invention includes copper with a mass percentage of 38-40%, preferably 39-40%.

[0021] The elemental composition of the anode alloy for producing refined aluminum using the three-layer liquid electrolysis method provided by this invention includes aluminum with a mass percentage of 60-62%, preferably 60-61%.

[0022] In this invention, the primary crystallization temperature for producing the anode alloy for refined aluminum using the three-layer liquid electrolysis method is preferably 547–565°C, more preferably 557–565°C, and the density is preferably 3.22–3.28 g / cm³. 3 More preferably, it is 3.27–3.28 g / cm³. 3 The electrical conductivity is preferably 1.30-1.34 A / Ω·cm, more preferably 1.31-1.34 A / Ω·cm, the current efficiency is preferably 99.97-100%, more preferably 99.98-100%, and the production temperature is preferably 751-762℃, more preferably 751-760℃.

[0023] The anode alloy for producing refined aluminum using the three-layer liquid electrolysis method provided by this invention has a reasonable copper-aluminum ratio, a relatively low primary crystallization temperature (547–565℃), and relatively high electrical conductivity (1.30–1.34 A / Ω·cm) and current efficiency (99.97–100%), which is closer to the process requirements for refining refined aluminum using the three-layer liquid electrolysis method. The alloy density is 3.22–3.28 g / cm³. 3 This process facilitates the separation of the anode alloy with the electrolyte, resulting in a smoother alloy that is less prone to floating. The copper concentration is also beneficial for the electrochemical reaction of aluminum within the alloy. The production temperature (751–762℃) is optimal for the three-layer electrolytic refining of aluminum, preventing the precipitation of alloy impurities and ensuring a stable and continuous production process. This reduces the energy consumption per unit volume of the refined aluminum solution and improves the quality of the refined aluminum. Furthermore, the anode alloy used in this three-layer electrolytic method facilitates the control of the three-layer aluminum production process and allows for automated alloy stirring in the feed chamber, avoiding contamination caused by manual stirring.

[0024] This invention also provides a method for preparing anode alloys for producing refined aluminum using the three-layer liquid electrolysis method described in the above technical solution, comprising the following steps:

[0025] After electrolytic copper and electrolytic aluminum are smelted, the resulting melt is subjected to primary purification, slag removal, and secondary purification in sequence to obtain an anode alloy for producing refined aluminum by the three-layer liquid electrolysis method.

[0026] Unless otherwise specified, the present invention does not have special requirements on the source of the raw materials used in the preparation, and commercially available products well known to those skilled in the art can be used.

[0027] This invention involves smelting electrolytic copper and electrolytic aluminum to obtain a melt.

[0028] In this invention, the mass percentage of copper in the electrolytic copper is preferably ≥99.95%, more preferably ≥99.96%.

[0029] In this invention, the mass percentage of aluminum in the electrolytic aluminum is preferably ≥99.8%, more preferably ≥99.9%.

[0030] In this invention, the electrolytic copper conforms to the T10900 standard of GB / T5231-2022 "Grades and Chemical Compositions of Processed Copper and Copper Alloys", with a copper content of ≥99.95% by mass. In this invention, the electrolytic copper is in the shape of a rectangular plate with a thickness of 5 mm.

[0031] In this invention, the electrolytic copper meets or exceeds the A199.80 aluminum grade standard in GB / T1196-2017 Aluminum Ingots for Remelting. In this invention, the electrolytic aluminum is liquid aluminum and is transported in aluminum ladles.

[0032] In this invention, the melting process preferably includes: first heating from room temperature to 660°C, and then second heating from 660°C to 750°C; the second heating time is preferably 4-5 hours, more preferably 4-4.5 hours. This invention does not have a specific limitation on the first heating time, which can be selected according to actual needs.

[0033] In this invention, the smelting is carried out in a refined aluminum bath; the current of the refined aluminum bath is preferably 90-100kA, more preferably 95-100kA, and the voltage is preferably 4.0-4.5V, more preferably 4.1-4.3V.

[0034] Before smelting, the present invention preferably further includes: drying the raw copper and raw aluminum; the drying temperature is preferably 170-175°C, more preferably 170°C; the drying time is preferably 3-4 hours, more preferably 3 hours.

[0035] After obtaining the melt, the present invention sequentially performs a first purification, slag removal and a second purification on the melt to obtain an anode alloy for producing refined aluminum by three-layer liquid electrolysis.

[0036] In this invention, the first purification process preferably includes: a third temperature increase from 750°C to 780°C; the third temperature increase time is preferably 3 to 4 hours, more preferably 4 hours.

[0037] In this invention, the temperature of the secondary purification is preferably 780-790°C, more preferably 780°C, and the heat preservation time is preferably 2-4 hours, more preferably 3-4 hours.

[0038] This invention improves the copper-aluminum ratio in the anode alloy, optimizes the alloy density, lowers the primary crystallization temperature, increases the alloy conductivity, improves the working temperature at the material chamber inlet, reduces alloy slag precipitation, and reduces the impact on the quality of refined aluminum production. The copper-aluminum alloy ratio is more scientific and more conducive to the control of the three-layer liquid refined aluminum production process. It can also realize automated alloy stirring in the material chamber, avoiding contamination of the alloy caused by manual stirring.

[0039] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, but they should not be construed as limiting the scope of protection of the present invention.

[0040] Example 1

[0041] After drying the raw materials copper and aluminum at 170℃ for 3 hours, the refined aluminum tank was preheated by electricity. 380 kg of electrolytic copper (copper content ≥99.95%) and 620 kg of electrolytic aluminum (aluminum content ≥99.8%) were weighed and added separately. After all materials were added, the refined aluminum tank was heated by electricity (4.5V, 100kA) from room temperature to 660℃, at which point the aluminum began to melt. Within 5 hours, the temperature was increased from 660℃ to 750℃, during which time the electrolytic copper began to melt synchronously in the aluminum liquid. Then, within 4 hours, the temperature was increased from 750℃ to 780℃ for a first purification. After slag removal, a second purification was performed at 780℃ for 4 hours. After sampling and analysis, the obtained anode alloy for producing refined aluminum using the three-layer electrolysis method was added to refined aluminum tank #1. The production status of tank #1 was monitored, and the results are shown in Table 1.

[0042] Primary crystallization temperature testing method: Thermal analysis is used, which records the time-temperature relationship curve of the sample during heating or cooling. If no transformation occurs in the system during heating or cooling, the time-temperature curve shows a regular and continuous change; if some transformation occurs in the system, it is accompanied by exothermic and endothermic phenomena, and inflection points and horizontal sections will appear on the heating or cooling curve. The temperature at which the transformation occurs can be determined based on these inflection points or pause points.

[0043] The conductivity test method is the AC bridge method, which is used to directly measure the conductivity.

[0044] Table 1. Experimental results of tank #1

[0045]

[0046] As shown in Table 1, the experiment was conducted in cell #1 according to the formula. Based on the production experiment results, the conductivity was 1.30-1.32 A / Ω·cm, the initial crystallization temperature was 547-552℃, the separation between the anode alloy and the electrolyte was clear, there was no alloy floating, and the alloy crystallization temperature was relatively low. After a period of observation, the anode alloy of this formula showed little process fluctuation and stable product quality during the production of refined aluminum by the three-layer electrolyte electrolysis method.

[0047] Example 2

[0048] After drying the raw materials copper and aluminum at 170℃ for 3 hours, the aluminum refinement tank was preheated by electricity. 390 kg of electrolytic copper (copper content ≥99.95%) and 610 kg of electrolytic aluminum (aluminum content ≥99.8%) were weighed and added to the aluminum refinement tank. After all materials were added, the aluminum refinement tank was heated (4.5V, 100kA) from room temperature to 660℃, at which point the aluminum began to melt. Within 5 hours, the temperature was raised from 660℃ to 750℃, during which time the electrolytic copper began to melt synchronously in the aluminum melt. Then, within 4 hours, the temperature was raised from 750℃ to 780℃ for a first purification. After slag removal, a second purification was performed at 780℃ for 4 hours. After sampling and analysis, the resulting anode alloy for producing refined aluminum using the three-layer electrolysis method was added to aluminum refinement tank #2. The production status of tank #2 was monitored, and the results are shown in Table 2.

[0049] Table 2 Experimental results of tank #2

[0050]

[0051] As shown in Table 2, the alloy density was 3.24–3.25 g / cm³ when the experiment was conducted in tank #2 according to this formula. Based on the production experiment results, the alloy density was determined to be 3.24–3.25 g / cm³. 3 The initial crystallization temperature is 555-560℃, with clear separation between the anode and electrolyte, no alloy floating, and a relatively low crystallization temperature. Through a period of observation, the anode alloy of this formula has shown stable process in the production of refined aluminum using the three-layer electrolyte electrolysis method. The copper concentration is more conducive to the electrochemical reaction of aluminum in the alloy, resulting in higher current efficiency and reduced production costs.

[0052] Example 3

[0053] After drying the raw materials copper and aluminum at 170℃ for 3 hours, the aluminum refinement tank was preheated by electricity. 400 kg of electrolytic copper (copper content ≥99.95%) and 600 kg of electrolytic aluminum (aluminum content ≥99.8%) were weighed and added to the aluminum refinement tank. After all materials were added, the aluminum refinement tank was heated (4.5V, 100kA) from room temperature to 660℃, at which point the aluminum began to melt. Within 5 hours, the temperature was raised from 660℃ to 750℃, during which time the electrolytic copper began to melt synchronously in the aluminum melt. Then, within 4 hours, the temperature was raised from 750℃ to 780℃ for a first purification. After slag removal, a second purification was performed at 780℃ for 4 hours. After sampling and analysis, the resulting anode alloy for producing refined aluminum using the three-layer electrolysis method was added to aluminum refinement tank #3. The production status of tank #3 was monitored, and the results are shown in Table 3.

[0054] Table 3. Experimental results of tank #3

[0055]

[0056] As shown in Table 3, the experiment was conducted in cell #3 according to this formula. Based on the production experiment results, the conductivity was 1.31–1.34 A / Ω·cm, the initial crystallization temperature was 557–565℃, the separation between the anode and electrolyte was clear, there was no alloy floating, and the alloy crystallization temperature was relatively low. After a period of observation, the anode alloy of this formula showed stable product quality, high conductivity, reduced power consumption, and reduced production costs during the production of refined aluminum using the three-layer electrolyte electrolysis method.

[0057] Comparative Example 1

[0058] After drying the raw materials copper and aluminum at 170℃ for 3 hours, the aluminum refinement tank was preheated by electricity. 370 kg of electrolytic copper (copper content ≥99.95%) and 630 kg of electrolytic aluminum (aluminum content ≥99.8%) were weighed and added to the aluminum refinement tank. After all materials were added, the aluminum refinement tank was heated (4.5V, 100kA) from room temperature to 660℃, at which point the aluminum began to melt. Within 5 hours, the temperature was raised from 660℃ to 750℃, during which time the electrolytic copper began to melt synchronously in the aluminum melt. Then, within 4 hours, the temperature was raised from 750℃ to 780℃ for a first purification. After slag removal, a second purification was performed at 780℃ for 4 hours. After sampling and analysis, the resulting anode alloy for producing refined aluminum using the three-layer electrolysis method was added to aluminum refinement tank #4. The production status of tank #4 was monitored, and the results are shown in Table 4.

[0059] Table 4 Production status of tank #4

[0060]

[0061] Table 4 shows that, based on the production experiment results obtained using this formula in tank #4, the electrical conductivity is 1.28–1.30 A / Ω·cm, and the alloy density is 3.07–3.10 g / cm³. 3 The initial crystallization temperature is 549-554℃. The alloy is disordered in the separation of the electrolyte and floats to the surface. Through observation over a period of time, it was found that the anode alloy of this formula has large process fluctuations in the production of refined aluminum by the three-layer electrolyte electrolysis method, resulting in a low yield of 99.996AL premium grade.

[0062] Comparative Example 2

[0063] After drying the raw materials copper and aluminum at 170℃ for 3 hours, the aluminum refinement tank was preheated by electricity. 430 kg of electrolytic copper (copper content ≥99.95%) and 570 kg of electrolytic aluminum (aluminum content ≥99.8%) were weighed and added to the aluminum refinement tank. After all materials were added, the aluminum refinement tank was heated (4.5V, 100kA) from room temperature to 660℃, at which point the aluminum began to melt. Within 5 hours, the temperature was increased from 660℃ to 750℃, during which time the electrolytic copper began to melt synchronously in the aluminum melt. Then, within 4 hours, the temperature was increased from 750℃ to 780℃ for a first purification. After slag removal, a second purification was performed at 780℃ for 4 hours. After sampling and analysis, the resulting anode alloy for producing refined aluminum using the three-layer electrolysis method was added to aluminum refinement tank #5. The production status of tank #5 was monitored, and the results are shown in Table 5.

[0064] Table 5 Production status of tank #5

[0065]

[0066] As shown in Table 5, the experiment was conducted in cell #5 according to this formula. Based on the production experiment results, the conductivity was 1.24–1.28 A / Ω·cm, and the initial crystallization temperature was 568–582℃. The initial crystallization temperature was relatively high, and alloy slag was precipitated. Through observation over a period of time, it was found that the anode alloy of this formula increased the power consumption during the production of refined aluminum using the three-layer liquid electrolysis method, leading to increased production costs and a significant impact on the quality of refined aluminum production.

[0067] The results of the comparative experiments of Examples 1-3 and Comparative Examples 1-2 are shown in Table 6.

[0068] Table 6 Production status of tanks 1-5

[0069]

[0070] As shown in Table 6, the anode alloy formula provided by the present invention is reasonable and meets the copper-aluminum alloy ratio of the three-layer liquid electrolytic aluminum refining process, with electrolytic copper: 38-40% and electrolytic aluminum: 60-62%. It can reduce the primary crystallization temperature, increase the conductivity and current efficiency, and make the production temperature more favorable for the three-layer liquid electrolytic aluminum refining process.

[0071] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention and not all embodiments. People can obtain other embodiments based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. An anode alloy for producing refined aluminum using a three-layer liquid electrolysis method, characterized in that, The following elemental components are included in the following mass percentages: Copper: 38-40%, Aluminum: 60-62%.

2. The anode alloy for producing refined aluminum using the three-layer liquid electrolysis method according to claim 1, characterized in that, The primary crystallization temperature of the anode alloy used in the three-layer liquid electrolysis method for producing refined aluminum is 547–565℃, and the density is 3.22–3.28 g / cm³. 3 Its conductivity is 1.30–1.34 A / Ω·cm, and its current efficiency is 99.97–100%.

3. The method for preparing anode alloys for producing refined aluminum by the three-layer liquid electrolysis method as described in claim 1 or 2, characterized in that, Includes the following steps: After electrolytic copper and electrolytic aluminum are smelted, the resulting melt is subjected to primary purification, slag removal, and secondary purification in sequence to obtain an anode alloy for producing refined aluminum by the three-layer liquid electrolysis method.

4. The preparation method according to claim 3, characterized in that, The electrolytic copper contains ≥99.95% copper by mass.

5. The preparation method according to claim 3, characterized in that, The electrolytic aluminum contains ≥99.8% aluminum by mass.

6. The preparation method according to claim 3, characterized in that, The smelting process includes: first heating from room temperature to 660°C, and then heating from 660°C to 750°C.

7. The preparation method according to claim 3 or 6, characterized in that, The smelting is carried out in a refined aluminum bath; the current in the refined aluminum bath is 90-100kA and the voltage is 4.0-4.5V.

8. The preparation method according to claim 6, characterized in that, The second heating time is 4 to 5 hours.

9. The preparation method according to claim 3, characterized in that, The first purification process includes: raising the temperature from 750°C to 780°C; the time for the third temperature increase is 3 to 4 hours.

10. The preparation method according to claim 3, characterized in that, The temperature for the secondary purification is 780–790℃, and the holding time is 2–4 hours.

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