Method for recycling copper and iron in copper-embedded cathode collector bar for aluminum electrolysis

Abstract

The invention provides a method for recycling copper and iron in a copper-embedded cathode collector bar for aluminum electrolysis, and belongs to the field of aluminum electrolysis. The method comprises the following steps: measuring the copper content of the section of the copper-embedded cathode collector bar to respectively obtain copper equal content distribution curves c1, c2 and c3 of the copper-embedded cathode collector bar; based on the copper equal-content distribution curve c1, the copper-embedded cathode collector bar is subjected to first-round cutting, and a metal block 1 with the copper content smaller than or equal to m1 is obtained; based on the copper equal-content distribution curve c2, the copper-embedded cathode collector bar obtained after the first round of cutting is subjected to second round of cutting, and a metal block 2 with the copper content ranging from m1 to m2 is obtained; and based on the copper equal-content distribution curve c3, the copper-embedded cathode collector bar obtained after the second round of cutting is subjected to third round of cutting, and a metal block 3 with the copper content being m < 2 >-m < 3 > and a metal block 4 with the copper content being larger than m < 3 > are obtained. Therefore, the recovery rate of copper and iron in the copper-embedded cathode collector bar for aluminum electrolysis is improved.

Description

Technical Field

[0001] The present application relates to the technical field of aluminum electrolysis, and in particular to a method for recovering copper and iron from copper-embedded cathode current collector rods used in aluminum electrolysis. Background Art

[0002] As the aluminum industry's dual energy consumption control targets become increasingly stringent, energy conservation in the aluminum electrolysis process has become more urgent. Reducing the voltage drop in the conductor section of the aluminum electrolysis system is an effective method. Currently, some companies have replaced the traditional iron-based cathode collector rods with all-copper cathode collector rods or copper-iron composite copper-embedded cathode collector rods, achieving good energy-saving and consumption-reducing effects. The use of these copper-containing cathode collector rods not only significantly reduces the bottom voltage drop of the electrolytic cell, but also can reduce the horizontal current of the aluminum liquid to a certain extent, reducing the cell voltage and improving the current efficiency.

[0003] Using all-copper cathode collector rods or copper-iron composite copper-embedded cathode collector rods significantly increases the cost of electrolytic cell overhauls. To reduce costs, efficient copper recovery from the cathode collector rods is required after the electrolytic cell is shut down. While all-copper collector rods are relatively easy to recycle, copper-iron composite copper-embedded cathode collector rods, exposed to high temperatures for extended periods, experience interpenetration between the copper and iron interfaces, making recycling difficult and resulting in lower copper and iron recovery rates. Therefore, improving the recovery rate of copper and iron from copper-embedded cathode collector rods used in aluminum electrolysis is a pressing technical challenge. Summary of the Invention

[0004] The present application provides a method for recovering copper and iron from copper-embedded cathode current collector rods for aluminum electrolysis, in order to solve the following technical problem: how to improve the recovery rate of copper and iron from copper-embedded cathode current collector rods for aluminum electrolysis.

[0005] The present application provides a method for recovering copper and iron from copper-embedded cathode current collector rods for aluminum electrolysis, the method comprising:

[0006] Determine the copper content of the cross section of the copper-embedded cathode current collector rod to obtain a copper content distribution curve c1, a copper content distribution curve c2, and a copper content distribution curve c3 of the copper-embedded cathode current collector rod; wherein the copper contents of the copper content distribution curve c1, the copper content distribution curve c2, and the copper content distribution curve c3 are m1, m2, and m3, respectively;

[0007] Based on the copper content distribution curve c1, the copper-embedded cathode current collector rod is cut in the first round to obtain a metal block 1 with a copper content ≤ m1;

[0008] Based on the copper content distribution curve c2, the copper-embedded cathode current collector rod after the first round of cutting is subjected to a second round of cutting to obtain a metal block 2 with a copper content of m1 to m2; and

[0009] Based on the copper content distribution curve c3, the copper-embedded cathode current collector rod after the second round of cutting is subjected to a third round of cutting to obtain a metal block 3 with a copper content of m2 to m3 and a metal block 4 with a copper content greater than m3;

[0010] Each round of cutting includes three steps of cutting. The first step of cutting is generally perpendicular to the length direction of the current collector bar, the second step of cutting is generally perpendicular to the height direction of the current collector bar, and the third step of cutting is generally perpendicular to the width direction of the current collector bar.

[0011] Optionally, the copper content of the copper content distribution curve c1 is 0.4%.

[0012] Optionally, the copper content m2 of the copper content distribution curve c2 satisfies the following relationship:

[0013] m2=C Fe / (C Fe +C Cu )

[0014] Where, the unit is %; C Fe Indicates the market price of iron (ordinary carbon steel, the same below), in yuan / ton; C Cu It represents the market price of copper (cathode copper, the same below), in Yuan / ton.

[0015] Optionally, the copper content m3 of the copper content distribution curve c3 satisfies the following relationship:

[0016] If 10C Fe / (C Fe +C Cu )≥90%, then m3 is 90%;

[0017] If 10C Fe / (C Fe +C Cu )<90%, then m3 is 10C Fe / (C Fe +C Cu );

[0018] Among them; C Fe Indicates the market price of iron, in yuan / ton; C Cu Indicates the market price of copper, in yuan / ton.

[0019] Optionally, the method further includes:

[0020] The metal block 1 is used to recover iron;

[0021] The metal block 2 is subjected to matte smelting to separate copper and iron to obtain iron and copper matte;

[0022] The metal block 3 is used to prepare copper-iron alloy;

[0023] The metal block 4 is subjected to high-temperature oxidation refining to selectively remove iron to obtain crude copper.

[0024] Optionally, the first round of cutting adopts saw cutting, plasma cutting or flame cutting.

[0025] Optionally, the second round of cutting adopts wire cutting or laser cutting.

[0026] Optionally, the third round of cutting adopts wire cutting or laser cutting.

[0027] Optionally, the metal chips obtained from each round of cutting are collected separately to improve the recovery rate of copper and iron.

[0028] Optionally, the copper recovery rate of the copper-embedded cathode current collector rod is ≥99%, and the iron recovery rate is ≥97%.

[0029] The above technical solution provided by the embodiment of the present application has the following advantages compared with the prior art:

[0030] An embodiment of the present application provides a method for recovering copper and iron from copper-embedded cathode current collector rods for aluminum electrolysis, the method comprising: determining the copper content of a cross-section of the copper-embedded cathode current collector rod, and obtaining a copper equal content distribution curve c1, a copper equal content distribution curve c2, and a copper equal content distribution curve c3 of the copper-embedded cathode current collector rod, respectively; wherein the copper contents of the copper equal content distribution curve c1, the copper equal content distribution curve c2, and the copper equal content distribution curve c3 are m1, m2, and m3, respectively; based on the copper equal content distribution curve c1, the copper-embedded cathode current collector rod is subjected to a first round of cutting to obtain a metal block 1 with a copper content ≤ m1; based on the copper equal content distribution curve c2, the copper-embedded cathode current collector rod after the first round of cutting is subjected to a second round of cutting to obtain a metal block 2 with a copper content of m1 to m2; and based on the copper equal content distribution curve c3, the copper-embedded cathode current collector rod after the second round of cutting is subjected to a third round of cutting to obtain a metal block 3 with a copper content of m2 to m3 and a metal block 4 with a copper content > m3. When copper-iron composite copper-embedded cathode current collector rods are exposed to high temperatures for a long time, the copper and iron interfaces interpenetrate, forming three curves: copper content distribution curve c1, copper content distribution curve c2, and copper content distribution curve c3. Copper content distribution curve c1 represents the minimum economic recovery threshold at the copper diffusion front. Regions below this value are primarily iron, allowing for efficient iron recovery. Copper content distribution curve c2 serves as a dynamic demarcation point based on the market prices of copper and iron, balancing recovery economics. Copper content distribution curve c3 prevents high-copper regions from failing due to excessive refining costs, dynamically adjusting the upper purity limit. Each cutting cycle consists of three steps: the first step is generally perpendicular to the length of the current collector rod, the second step is generally perpendicular to the height of the current collector rod, and the third step is generally perpendicular to the width of the current collector rod. Each cutting cycle proceeds in three dimensions, reducing the contact area of ​​each cut and preventing contamination of high-copper regions with cutting debris. This improves the recovery rate of copper and iron in copper-embedded cathode current collector rods for aluminum electrolysis. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0032] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0033] Figure 1 A schematic flow chart of a method for recovering copper and iron from copper-embedded cathode current collector rods for aluminum electrolysis provided in an embodiment of the present application;

[0034] Figure 2A schematic diagram of the cutting direction for the first step of cutting the copper-embedded cathode current collector rod provided in an embodiment of the present application;

[0035] Figure 3 A schematic diagram of the cutting direction for the second step of cutting the copper-embedded cathode current collector rod provided in an embodiment of the present application;

[0036] Figure 4 A schematic diagram of the cutting direction for the third step of cutting the copper-embedded cathode current collector rod provided in an embodiment of the present application;

[0037] Reference numerals:

[0038] 1-cutting direction; 2-current collecting rod. DETAILED DESCRIPTION

[0039] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0040] Various embodiments of the present application may be presented in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity and should not be understood as a hard limitation on the scope of the present application; therefore, the range description should be considered to have specifically disclosed all possible sub-ranges and single numbers within the range. For example, the description of a range from 1 to 6 should be considered to have specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the range, such as 1, 2, 3, 4, 5 and 6, which applies regardless of the range. In addition, whenever a numerical range is indicated herein, it is meant to include any cited number (fractional or integer) within the indicated range.

[0041] In addition, in the description of the specification of this application, the terms "including", "comprising", etc. mean "including but not limited to". In this article, relational terms such as "first" and "second" are merely used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. In this article, "and / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. Wherein A and B can be singular or plural. In this article, "at least one" refers to one or more, and "plurality" refers to two or more. "At least one", "at least one of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, "at least one of a, b, or c", or "at least one of a, b, and c", can all represent: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, c can be single or multiple. "Parts" such as parts by weight and parts by mass represent the proportional relationship between the components. In the proportional relationship involved in this article, the parameters that need to be described by proportion should be understood as the first term of the proportional formula in the order of description, and the proportional numbers should be understood as the second term of the proportional formula. For example, if the mass ratio of substance A, substance B, and substance C is 1:2:3, then substance A, substance B, and substance C should correspond one-to-one to the proportional numbers in the proportional formula in the order of description, that is, the mass of substance A: the mass of substance B: the mass of substance C = 1:2:3.

[0042] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this application can be purchased from the market or prepared by existing methods.

[0043] The use of copper-iron composite cathode collector rods embedded with copper can achieve good energy conservation and consumption reduction effects, but it also increases enterprise costs. The copper-iron composite cathode collector rods embedded with copper are exposed to high temperatures for a long time, and the copper-iron interface penetrates each other, making recycling difficult.

[0044] The present application thus provides a method for recovering copper and iron from copper-embedded cathode current collector rods for aluminum electrolysis. This method can provide conditions for efficiently recovering copper and iron from copper-embedded cathode current collector rods for aluminum electrolysis, and provide technical support for enterprises that use energy-saving technology of copper-embedded cathode current collector rods using a copper-iron composite to reduce their operating costs.

[0045] The technical solution adopted by the present invention to solve its technical problem is:

[0046] Figure 1A schematic flow chart of a method for recovering copper and iron from copper-embedded cathode current collector rods for aluminum electrolysis provided in an embodiment of the present application.

[0047] like Figure 1 As shown, the present application provides a method for recovering copper and iron from copper-embedded cathode current collector rods for aluminum electrolysis, the method comprising:

[0048] S1. Determine the copper content of a cross-section of a copper-embedded cathode current collector rod to obtain a copper content distribution curve c1, a copper content distribution curve c2, and a copper content distribution curve c3 of the copper-embedded cathode current collector rod; wherein the copper contents of the copper content distribution curve c1, the copper content distribution curve c2, and the copper content distribution curve c3 are m1, m2, and m3, respectively;

[0049] S2. Based on the copper content distribution curve c1, the copper-embedded cathode current collector rod is cut for the first time to obtain a metal block 1 with a copper content ≤ m1;

[0050] S3, based on the copper content distribution curve c2, the copper-embedded cathode current collector rod after the first round of cutting is subjected to a second round of cutting to obtain a metal block 2 with a copper content of m1 to m2; and

[0051] S4, based on the copper content distribution curve c3, the copper-embedded cathode current collector rod after the second round of cutting is subjected to a third round of cutting to obtain a metal block 3 with a copper content of m2 to m3 and a metal block 4 with a copper content greater than m3;

[0052] Each round of cutting includes three steps of cutting. The first step of cutting is generally perpendicular to the length direction of the current collector bar, the second step of cutting is generally perpendicular to the height direction of the current collector bar, and the third step of cutting is generally perpendicular to the width direction of the current collector bar.

[0053] It should be noted that due to different design sizes of collector bars, sometimes individual wheel cutting may require less than three steps.

[0054] The copper-iron composite embedded copper cathode current collector rod is exposed to high temperature for a long time, and the copper-iron interface penetrates each other, thus forming three curves: copper content distribution curve c1, copper content distribution curve c2 and copper content distribution curve c3. Copper content distribution curve c1: the lowest economic recovery threshold of the copper diffusion front. The area below this value is mainly iron, and iron can be efficiently recovered. Copper content distribution curve c2 (C Fe / (C Fe +C Cu )):Based on the dynamic dividing point of copper and iron market prices, balance the recycling economy (for example, when copper prices are high, high copper areas are recycled first). Copper content distribution curve c3(min{10C Fe / (C Fe +C Cu),90%}): Prevent high copper areas (≥90%) from failing due to high refining costs and dynamically adjust the purity limit.

[0055] In some embodiments, the copper content of the copper content distribution curve c1 is 0.4%.

[0056] In some embodiments, the copper content m2 of the copper content distribution curve c2 satisfies the following relationship:

[0057] m2=C Fe / (C Fe +C Cu )

[0058] Where, the unit is %; C Fe Indicates the market price of iron, in yuan / ton; C Cu Indicates the market price of copper, in yuan / ton.

[0059] In some embodiments, the copper content m3 of the copper content distribution curve c3 satisfies the following relationship:

[0060] If 10C Fe / (C Fe +C Cu )≥90%, then m3 is 90%;

[0061] If 10C Fe / (C Fe +C Cu )<90%, then m3 is 10C Fe / (C Fe +C Cu );

[0062] Among them; C Fe Indicates the market price of iron, in yuan / ton; C Cu Indicates the market price of copper, in yuan / ton.

[0063] In some embodiments, the method further comprises:

[0064] The metal block 1 is used to recover iron;

[0065] The metal block 2 is subjected to matte smelting to separate copper and iron to obtain iron and copper matte;

[0066] The metal block 3 is used to prepare copper-iron alloy;

[0067] The metal block 4 is subjected to high-temperature oxidation refining to selectively remove iron to obtain crude copper.

[0068] The copper content of the copper content distribution curve c1 is 0.4%, which can be used to determine a baseline copper content. Metal blocks with a copper content below this level are mainly used for iron recovery. Alloys with a copper content below 0.4% have relatively low economic value of copper and are more suitable for iron resource recovery.

[0069] The copper content of the copper content distribution curve c2 is CFe / (CFe+CCu), and the economic balance point of copper and iron can be dynamically adjusted based on market prices. When the copper content is between c1 and c2, copper and iron can be efficiently separated by matte smelting, generating copper matte (Cu2S) containing 40% to 60% copper and a metal phase containing more than 95% iron, achieving initial enrichment of the two metals. For example, if the price of iron is 4,000 yuan / ton and the price of copper is 70,000 yuan / ton, then m2 = 4,000 / (4,000+70,000) = 5.4%.

[0070] The copper content of the copper content distribution curve C3 is m3. C3 can be used to distinguish between processing paths for high- and medium-copper alloys and identify copper-iron alloys suitable for alloying and refining. Metal block 3 (m2-m3) is used to formulate copper-iron alloys (such as wear-resistant bearing materials). Metal block 4 (>m3) undergoes high-temperature oxidative refining to selectively remove iron, resulting in crude copper. This is then electrolytically refined to obtain high-purity copper (≥99.95%).

[0071] Each cutting cycle consists of three steps: the first is perpendicular to the length of the current collector bar, the second is perpendicular to the height of the current collector bar, and the third is perpendicular to the width of the current collector bar. Each cutting cycle proceeds in three dimensions, reducing the contact area of ​​each cut and preventing contamination of high-copper areas with cutting debris. This reduces metal loss and minimizes the area swept by the cutting.

[0072] In some embodiments, the first cutting process is performed by saw cutting, plasma cutting or flame cutting.

[0073] In some embodiments, the second cutting round is performed by wire cutting or laser cutting.

[0074] In some embodiments, the third round of cutting uses wire cutting or laser cutting.

[0075] The first round of cutting uses saw cutting, plasma cutting or flame cutting, which is suitable for efficient cutting of large pieces of material and quickly removes a large number of low-copper areas, thereby improving cutting efficiency and reducing processing costs.

[0076] The second and third rounds of cutting use wire cutting or laser cutting, which are high-precision cutting and can reduce copper loss.

[0077] In some embodiments, the copper content of the current collector bar cross section is measured using an X-ray fluorescence spectrometer.

[0078] In some embodiments, metal chips obtained from each round of cutting are collected separately to improve the recovery rate of copper and iron.

[0079] In some embodiments, the copper recovery rate of the copper-embedded cathode current collector rod is ≥99%, and the iron recovery rate is ≥97%.

[0080] In summary, this application solves the pain points of resource waste, high cost, and heavy pollution in traditional processes through the innovative combination of "dynamic threshold cutting + three-dimensional precise separation + full-process efficient recycling", providing a breakthrough solution for the green and efficient recycling of waste collector rods in the aluminum electrolysis industry, with both economic and environmental benefits and industrial application value. Specifically, it has the following advantages:

[0081] 1. Dynamic threshold design based on market prices to maximize resource economic benefits

[0082] (1) Cutting strategy driven by economic balance point:

[0083] c1 (0.4%): Based on the minimum economic recovery threshold of copper resources (0.4%), low-copper areas (≤0.4%) are directly classified as iron recovery paths to avoid ineffective treatment of low-grade copper and reduce iron recovery costs.

[0084] c2(C Fe / (C Fe +C Cu The separation threshold is dynamically adjusted based on the real-time market price of copper and iron. For example, the higher the copper price, the smaller the c2 value, allowing more areas to be allocated to high-value copper recycling. For example, with an iron price of 4,000 yuan / ton and a copper price of 70,000 yuan / ton, c2 = 5.4%, ensuring the optimal input-output ratio for copper and iron separation.

[0085] c3(min{10C Fe / (C Fe +C Cu ), 90%}): Set the upper limit of copper content (90%) to avoid the economic decline of high copper areas due to excessive refining costs. When copper prices are low (such as C Fe / C Cu ratio increases), C3 is automatically reduced to 10C2 to balance the benefits of alloy preparation and refining paths.

[0086] Optimization of economic benefits throughout the entire process:

[0087] The four-level classification of metal block 1 (iron recovery), metal block 2 (matte smelting), metal block 3 (alloy preparation), and metal block 4 (refining and copper extraction) enables different copper content areas to match the most efficient recycling process, avoiding the waste of resources from "high copper and low smelting" or "low copper and high smelting".

[0088] Combining two- and three-dimensional cutting technology with precision detection to achieve low-loss and high-efficiency separation

[0089] (1) Multi-directional layered cutting technology:

[0090] Three-round three-dimensional cutting (length → height → width): The collector rod is peeled off step by step in the three-dimensional direction. A single cut only touches a single-dimensional cross-section, reducing the friction area between the high-copper area and the cutting tool, making the metal loss rate less than 1% (the loss rate of the traditional one-size-fits-all process is about 3% to 5%).

[0091] (2) Cutting process adaptation:

[0092] The first round (flame / plasma cutting): quickly removes low-copper iron shells (accounting for about 60% to 70%), with an efficiency of up to 100cm / min and a cost reduction of more than 50% compared to traditional wire cutting.

[0093] Second round / third round (wire cutting / laser cutting): cutting seam width <0.5mm, heat-affected zone <1mm, to avoid high copper area from melting due to overheating and mixing with scrap, and reduce copper loss rate by 80% compared with traditional cutting.

[0094] (3) Rapid detection and precise positioning:

[0095] An X-ray fluorescence spectrometer (detection speed <1min / point) is used to map the copper content distribution in real time, and the cutting path is generated by combining 3D modeling technology, so that the threshold positioning accuracy reaches ±0.2% copper content, avoiding misjudgment caused by manual cutting experience.

[0096] 3. High recovery rate and environmental benefits throughout the entire process

[0097] (1) Metal recovery rate breaks through industry bottlenecks:

[0098] Copper recovery rate ≥ 99%: Through three-stage cutting + metal chip recovery (collection efficiency > 95%), the copper recovery rate is improved compared with traditional processes.

[0099] (2) Iron recovery rate ≥ 97%: Direct magnetic separation recovery in low-copper areas, and iron enrichment in high-copper areas through matte smelting (metallic phase iron content > 95%), with an iron loss rate of < 3% (the loss rate of traditional acid leaching process is about 5% to 8%).

[0100] (3) Green and environmentally friendly process path

[0101] Avoid using strong acid (such as sulfuric acid) or cyanide leaching to reduce wastewater treatment costs; the matte smelting and oxidation refining process adopts a closed furnace type, and the exhaust gas is discharged after desulfurization treatment (SO2 < 200mg / m 3 ). Cutting waste (metal chips, slag) is 100% recycled, with no solid waste discharged, in line with the requirements of the circular economy.

[0102] The present application will be further described below in conjunction with specific examples. It should be understood that these examples are intended to illustrate the present application only and are not intended to limit the scope of the present application. The experimental methods in the following examples where specific conditions are not specified are generally measured according to industry standards. If there are no corresponding industry standards, then the methods are carried out according to general international standards, conventional conditions, or the conditions recommended by the manufacturer.

[0103] Example 1

[0104] After shutting down an electrolytic cell, the cathode was cleaned and the cathode current collector rods were separated. After removing the carbon debris and oxide layer from the surface, one cathode current collector rod weighed 260.10 kg, containing 29.08 kg of copper, calculated based on the design quantity. During a certain period, the price of copper was 48,752 yuan / ton, and the price of iron was 4,181 yuan / ton. Three copper content distribution curves showed copper contents of 0.4%, 7.90%, and 78.99%, respectively. The copper content of the current collector rod cross-section was determined using a rapid X-ray fluorescence spectrometer. Based on the three copper content distribution curves, the copper-embedded cathode current collector rods were cut three times. Each cutting round consisted of three steps: the first step was generally perpendicular to the length of the current collector rod, the second step was generally perpendicular to the height of the current collector rod, and the third step was generally perpendicular to the width of the current collector rod. The first round of cutting was performed using a saw, while the second and third rounds were performed using wire cutting. The resulting metal blocks are shown in the following table.

[0105] Table 1 Pretreatment results of copper and iron in a copper-embedded cathode current collector rod for aluminum electrolysis

[0106]

[0107]

[0108] Example 2

[0109] After shutting down an electrolytic cell, the cathode was cleaned and the cathode current collector rods were separated. After removing the carbon debris and oxide layer from the surface, one cathode current collector rod weighed 419.32 kg, containing 97.59 kg of copper, calculated based on the design quantity. During a certain period, the price of copper was 68,490 yuan / ton, and the price of iron was 5,160 yuan / ton. Three copper content distribution curves showed copper contents of 0.4%, 7.01%, and 70.06%, respectively. The copper content of the current collector rod cross-section was determined using a rapid X-ray fluorescence spectrometer. Based on the three copper content distribution curves, the copper-embedded cathode current collector rods were cut three times. Each cutting round consisted of three steps: the first step was generally perpendicular to the length of the current collector rod, the second step was generally perpendicular to the height of the current collector rod, and the third step was generally perpendicular to the width of the current collector rod. The first round of cutting was performed using a saw, while the second and third rounds were performed using laser cutting. The resulting metal blocks are shown in the following table.

[0110] Table 2 Pretreatment results of copper and iron in a copper-embedded cathode current collector rod for aluminum electrolysis

[0111] Total weight / kg Copper weight / kg Iron weight / kg Metal 4 58.32 51.56 6.75 Metal 3 149.83 43.20 106.64 Metal 2 64.18 2.04 62.14 Metal 1 141.46 0.01 141.46 total 413.80 96.81 316.99 Before splitting 419.32 97.59 321.73 Recovery rate / % 98.68 99.20 98.53

[0112] Example 3

[0113] After shutting down an electrolytic cell, the cathode was cleaned and the cathode current collector rods were separated. After removing the carbon debris and oxide layer from the surface, one cathode current collector rod weighed 200.20 kg, containing 25.45 kg of copper, calculated based on the design quantity. During a certain period, the price of copper was 67,019 yuan / ton, and the price of iron was 5,650 yuan / ton. Three copper content distribution curves showed copper contents of 0.4%, 7.77%, and 77.75%, respectively. The copper content of the current collector rod cross-section was determined using a rapid X-ray fluorescence spectrometer. Based on the three copper content distribution curves, the copper-embedded cathode current collector rods were cut three times. Each cutting round consisted of three steps: the first step was generally perpendicular to the length of the current collector rod, the second step was generally perpendicular to the height of the current collector rod, and the third step was generally perpendicular to the width of the current collector rod. Plasma cutting was used in the first round, while laser cutting was used in the second and third rounds. The resulting metal blocks are shown in the table below.

[0114] Table 3 Pretreatment results of copper and iron in a copper-embedded cathode current collector rod for aluminum electrolysis

[0115] Total weight / kg Copper weight / kg Iron weight / kg Metal 4 10.11 9.12 0.99 Metal 3 54.85 15.29 39.56 Metal 2 29.44 0.84 28.61 Metal 1 103.36 0.00 103.36 total 197.77 25.26 172.52 Before splitting 200.20 25.45 174.74 Recovery rate / % 98.79 99.22 98.72

[0116] Example 4

[0117] After shutting down an electrolytic cell, the cathode was cleaned and the cathode current collector rods were separated. After removing the carbon debris and oxide layer from the surface, one cathode current collector rod weighed 439.58 kg, containing 82.66 kg of copper, calculated based on the design quantity. During a certain period, the price of copper was 68,272 yuan / ton, and the price of iron was 4,490 yuan / ton. Three copper content distribution curves showed copper contents of 0.4%, 6.17%, and 61.71%, respectively. The copper content of the current collector rod cross-section was determined using a rapid X-ray fluorescence spectrometer. Based on the three copper content distribution curves, the copper-embedded cathode current collector rods were cut three times. Each cutting round consisted of three steps: the first step was generally perpendicular to the length of the current collector rod, the second step was generally perpendicular to the height of the current collector rod, and the third step was generally perpendicular to the width of the current collector rod. Flame cutting was used in the first round, while wire cutting was used in the second and third rounds. The resulting metal blocks are shown in the table below.

[0118] Table 4 Pretreatment results of copper and iron in copper-embedded cathode current collector rods for aluminum electrolysis

[0119] Total weight / kg Copper weight / kg Iron weight / kg Metal 4 60.53 55.16 5.37 Metal 3 123.71 24.91 98.80 Metal 2 52.75 1.80 50.95 Metal 1 194.52 0.01 194.51 total 431.52 81.88 349.63 Before splitting 439.58 82.66 356.91 Recovery rate / % 98.17 99.06 97.96

[0120] Example 5

[0121] After shutting down an electrolytic cell, the cathode was cleaned and the cathode current collector rods were separated. After removing the carbon debris and oxide layer from the surface, one cathode current collector rod weighed 221.43 kg, containing 28.59 kg of copper, calculated based on the design quantity. During a certain period, the price of copper was 75,019 yuan / ton, and the price of iron was 3,440 yuan / ton. Three copper content distribution curves showed copper contents of 0.4%, 4.38%, and 43.84%, respectively. The copper content of the current collector rod cross-section was determined using a rapid X-ray fluorescence spectrometer. Based on the three copper content distribution curves, the copper-embedded cathode current collector rods were cut three times. Each cutting round consisted of three steps: the first step was generally perpendicular to the length of the current collector rod, the second step was generally perpendicular to the height of the current collector rod, and the third step was generally perpendicular to the width of the current collector rod. Plasma cutting was used in the first round, while wire cutting was used in the second and third rounds. The resulting metal blocks are shown in the table below.

[0122] Table 5 Pretreatment results of copper and iron in a copper-embedded cathode current collector rod for aluminum electrolysis

[0123] Total weight / kg Copper weight / kg Iron weight / kg Metal 4 22.31 18.30 4.01 Metal 3 62.48 9.51 52.97 Metal 2 29.30 0.53 28.77 Metal 1 104.52 0.00 104.52 total 218.62 28.36 190.27 Before splitting 221.43 28.59 192.85 Recovery rate / % 98.73 99.19 98.66

[0124] Example 6

[0125] After shutting down an electrolytic cell, the cathode was cleaned and the cathode current collector rods were separated. After removing the carbon debris and oxide layer from the surface, one cathode current collector rod weighed 440.71 kg, containing 91.85 kg of copper, calculated based on the design quantity. During a certain period, the price of copper was 55,135 yuan / ton, and the price of iron was 5,520 yuan / ton. Three copper content distribution curves showed copper contents of 0.4%, 9.10%, and 90.00%, respectively. The copper content of the current collector rod cross-section was determined using a rapid X-ray fluorescence spectrometer. Based on the three copper content distribution curves, the copper-embedded cathode current collector rods were cut three times. Each cutting round consisted of three steps: the first step was generally perpendicular to the length of the current collector rod, the second step was generally perpendicular to the height of the current collector rod, and the third step was generally perpendicular to the width of the current collector rod. Plasma cutting was used in the first round, while wire cutting was used in the second and third rounds. The resulting metal blocks are shown in the table below.

[0126] Table 6 Pretreatment results of copper and iron in a copper-embedded cathode current collector rod for aluminum electrolysis

[0127]

[0128]

[0129] In addition, one or more technical solutions in the embodiments of the present application have at least the following technical effects or advantages:

[0130] In an embodiment of the present application, a method for recovering copper and iron from copper-embedded cathode current collector rods for aluminum electrolysis is provided. The method can provide conditions for efficiently recovering copper and iron from copper-embedded cathode current collector rods for aluminum electrolysis, and provide technical support for enterprises that use energy-saving technology of copper-embedded cathode current collector rods using a copper-iron composite to reduce their operating costs.

[0131] In the embodiment of the present application, the provided method can provide conditions for the efficient recovery of copper and iron in copper-embedded cathode current collector rods for aluminum electrolysis. The copper recovery rate in this process is higher than 99%, and the iron recovery rate is higher than 97%.

[0132] In the embodiment of the present application, in order to further reduce the loss of copper, the metal chips obtained in each round of cutting can be collected separately, and the copper recovery rate can be increased by 0.5% to 0.7%, and the iron recovery rate can be increased by 0.7% to 1.5%.

[0133] The foregoing is merely a list of specific embodiments of the present application, intended to enable those skilled in the art to understand or implement the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application is not limited to the embodiments shown herein, but is intended to conform to the broadest scope consistent with the principles and novel features of the present application.

Claims

1. A method for recovering copper and iron from copper-embedded cathode current collector rods for aluminum electrolysis, the method comprising: Determine the copper content of the cross section of the copper-embedded cathode current collector rod to obtain a copper content distribution curve c1, a copper content distribution curve c2, and a copper content distribution curve c3 of the copper-embedded cathode current collector rod; wherein the copper contents of the copper content distribution curve c1, the copper content distribution curve c2, and the copper content distribution curve c3 are m1, m2, and m3, respectively; Based on the copper content distribution curve c1, the copper-embedded cathode current collector rod is cut in the first round to obtain a metal block 1 with a copper content ≤ m1; Based on the copper content distribution curve c2, the copper-embedded cathode current collector rod after the first round of cutting is subjected to a second round of cutting to obtain a metal block 2 with a copper content of m1 to m2; and Based on the copper content distribution curve c3, the copper-embedded cathode current collector rod after the second round of cutting is subjected to a third round of cutting to obtain a metal block 3 with a copper content of m2 to m3 and a metal block 4 with a copper content greater than m3; Each round of cutting includes three steps of cutting. The first step of cutting is generally perpendicular to the length direction of the current collector bar, the second step of cutting is generally perpendicular to the height direction of the current collector bar, and the third step of cutting is generally perpendicular to the width direction of the current collector bar.

2. The method according to claim 1, characterized in that The copper content of the copper content distribution curve c1 is 0.4%.

3. The method according to claim 1, characterized in that The copper content m2 of the copper content distribution curve c2 satisfies the following relationship: m2=C Fe / (C Fe +C Cu ) Where, the unit is %; C Fe Indicates the market price of iron, in yuan / ton; C Cu Indicates the market price of copper, in yuan / ton.

4. The method according to claim 1, wherein The copper content m3 of the copper content distribution curve c3 satisfies the following relationship: If 10C Fe / (C Fe +C Cu )≥90%, then m3 is 90%; If 10C Fe / (C Fe +C Cu )<90%, then m3 is 10CFe / (C Fe +C Cu ); in; C Fe Indicates the market price of iron, in yuan / ton; C Cu Indicates the market price of copper, in yuan / ton.

5. The method according to claim 1, wherein The method further comprises: The metal block 1 is used to recover iron; The metal block 2 is subjected to matte smelting to separate copper and iron to obtain iron and copper matte; The metal block 3 is used to prepare copper-iron alloy; The metal block 4 is subjected to high-temperature oxidation refining to selectively remove iron to obtain crude copper.

6. The method according to claim 1, characterized in that The first round of cutting adopts saw cutting, plasma cutting or flame cutting.

7. The method according to claim 1, characterized in that The second round of cutting adopts wire cutting or laser cutting.

8. The method according to claim 1, characterized in that The third round of cutting adopts wire cutting or laser cutting.

9. The method according to claim 1, characterized in that The metal chips from each round of cutting are collected separately to improve the recovery rate of copper and iron.

10. The method according to claim 1, characterized in that The copper recovery rate of the copper-embedded cathode current collecting rod is ≥99%, and the iron recovery rate is ≥97%.

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