Preparation method for preparing oxygen-free copper through efficient impurity removal of regenerated copper

Abstract

The invention discloses a preparation method for preparing oxygen-free copper through efficient impurity removal of recycled copper, which comprises the following steps: heating and melting the recycled copper to obtain a recycled copper melt, and determining the content of copper element by adopting spectral analysis; oxygen is continuously introduced into the regenerated copper melt, impurity removal agent powder is weighed according to the content of impurity elements and sprayed into the furnace together with the oxygen to react with impurities in the melt, and the regenerated copper melt subjected to impurity removal is obtained; continuously introducing natural gas melt into the regenerated copper melt subjected to impurity removal, weighing deoxidant powder according to oxygen content in the natural gas melt, and spraying the deoxidant powder into the furnace by using the natural gas to react with oxygen in the melt, so as to obtain a regenerated copper melt subjected to oxygen removal; and standing the deoxidized regenerated copper melt, removing scum in the melt, and casting to obtain an oxygen-free copper product. According to the method, the impurity removal agent and the deoxidant powder are used in a combined mode, the time needed by oxygen impurity removal and natural gas reduction is shortened, the quality of the molten copper is improved, consumption of production materials is reduced, the production efficiency is improved, the production cost and pollution to the atmospheric environment are reduced, and the method is suitable for large-scale application.

Description

Technical Field

[0001] The present invention belongs to the technical field of copper smelting and copper recovery, and in particular relates to a method for preparing oxygen-free copper by utilizing recycled copper to efficiently remove impurities. Background Art

[0002] Due to its excellent electrical and thermal conductivity and processing properties, metallic copper is widely used in aerospace, rail transportation, electronic information and other fields. However, copper ore resources are severely scarce. Currently, domestic companies collect and sort recycled copper, then heat, melt and refine it in a reverberatory furnace to produce high-purity copper liquid, which is then cast and rolled into the required profiles. A 140T reverberatory furnace is commonly used to prepare copper liquid. 120T of recycled copper is added to the furnace for melting. After 4 hours of oxidation and impurity removal and 4 hours of natural gas reduction, the impurity element content can be controlled to the required range, and the oxygen content can be controlled to around 0.03%. However, this operation has the following disadvantages: 1. Oxidation and impurity removal are more effective when the impurity element content is high, but the effect is slower when the content is low, making it difficult to meet the requirements for preparing high-purity copper water; 2. The oxygen mixed in during the oxidation and impurity removal process increases the workload of subsequent natural gas reduction, and prolonged oxidation and impurity removal increases natural gas consumption; 3. Natural gas reduction is more effective when the oxygen content is high, but its efficiency decreases when it decreases to a certain level; 4. The 8-hour oxidation and impurity removal and natural gas reduction consume a lot of materials, affecting production costs and efficiency.

[0003] Therefore, there is an urgent need for a method for preparing oxygen-free copper by efficiently removing impurities from recycled copper. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for preparing oxygen-free copper by efficiently removing impurities from recycled copper. By adding impurity removers and deoxidizers during the preparation process, the consumption of production materials such as natural gas and oxygen is reduced, and the performance of the oxygen-free copper product is improved.

[0005] The present invention provides a method for preparing oxygen-free copper by efficiently removing impurities from recycled copper, comprising the following steps:

[0006] S1. The recycled copper is heated and melted to obtain a recycled copper melt, and the copper content is determined by spectral analysis as n, where n is expressed in wt.%;

[0007] S2. Oxygen is continuously introduced into the recycled copper melt for a preset time. During the oxygenation process, the impurity remover powder is weighed according to the impurity element content obtained in step S1, and the impurity remover powder is sprayed into the furnace together with oxygen to react with impurities in the melt to obtain a regenerated copper melt after impurity removal;

[0008] S3. After the impurities are removed, the regenerated copper melt is continuously fed with natural gas for a preset time, and the oxygen content in the melt is measured (s), where s is expressed in wt.%. The deoxidizer powder is weighed according to the oxygen content, and the deoxidizer powder is sprayed into the furnace using natural gas to react with oxygen in the melt to obtain a deoxidized regenerated copper melt.

[0009] S4. The deoxidized regenerated copper melt is allowed to stand, slag in the melt is removed, and the melt is cast to obtain an oxygen-free copper product.

[0010] Furthermore, in step S1, the heating and melting temperature is 1200-1300°C; the copper content measured by spectroscopy is a%, and the impurity elements include Zn, Fe, Ni, Sn, Mn, Cr, Mg, etc.

[0011] Furthermore, in step S2, the oxygen is introduced for a time of 0.8-1.2 minutes per ton, and the oxygen introduction rate is 5-9 cubic meters per minute based on the weight of the recycled copper raw material.

[0012] Furthermore, the impurity remover powder is a mixture of silica powder, sodium sulfide, calcium carbonate, chromium carbonate, calcium chloride, and sodium fluoroaluminate; wherein the ratio of silica powder, sodium sulfide, calcium carbonate, chromium carbonate, and calcium chloride is: 40-60: 10-30: 10-20: 4-6: 4-6: 4-6; the particle size of the impurity remover powder is 2 to 4 microns. Furthermore, the spray weight of the impurity remover powder is (0.8-1.2)*(1-100n)*2T / 1000, wherein n is the copper content; T is the melt weight in tons; and the impurity remover powder spraying time is 20 to 80 minutes.

[0013] Furthermore, in step S3, the time for introducing natural gas is 0.8-1.2 minutes per ton, and the speed of introducing natural gas is 4-8 cubic meters per minute based on the weight of the recycled copper raw material.

[0014] Furthermore, the preparation method of the deoxidizer powder is: smelting copper, magnesium, phosphorus, calcium, cerium and lanthanum in a mass ratio of 40-60:10-30:10-30:4-6:4-6 to obtain an alloy, and then ball milling the alloy to a particle size of 2 to 4 microns to obtain the deoxidizer powder.

[0015] Furthermore, the spraying weight of the deoxidizer powder is (800-1200)*s*T, wherein s is the oxygen content; T is the melt weight in tons; and the spraying time of the deoxidizer powder is 20 to 80 minutes.

[0016] Furthermore, in step S4, the standing time is 15 to 30 minutes.

[0017] Beneficial effects of the present invention:

[0018] (1) The method of the present invention provides an impurity remover powder that can quickly remove the remaining low-content impurities after oxidatively removing most of the impurities, thereby improving production efficiency and reducing production costs;

[0019] (2) The method of the present invention provides a deoxidizer powder that can quickly reduce the oxygen content after natural gas reduces most of the oxygen element, thereby improving production efficiency;

[0020] (3) The present invention combines the use of impurity remover and deoxidizer powder, which reduces the time required for oxygen impurity removal and natural gas reduction, improves the quality of copper liquid, and reduces the consumption of production materials. It not only improves production efficiency, but also reduces production costs and pollution to the atmospheric environment, and is suitable for large-scale application. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a metallographic diagram of the as-cast structure of the product obtained in Example 1;

[0022] Figure 2 Scanning electron microscope image of the as-cast structure of the product obtained in Example 1;

[0023] Figure 3 Tensile stress-strain curve of the alloy obtained in Example 1. DETAILED DESCRIPTION

[0024] Example 1

[0025] (1) Preparation of impurity remover: Silica powder, sodium sulfide, calcium carbonate, chromium carbonate, calcium chloride, and sodium fluoroaluminate were uniformly mixed in a mass ratio of 50:20:15:5:5:5 to prepare an impurity remover, and the mixture was ball-milled to 3 μm to obtain an impurity remover powder.

[0026] (2) Preparation of deoxidizer: pure copper, pure magnesium, pure phosphorus, pure calcium, pure cerium, and pure lanthanum were smelted at a mass ratio of 50:20:15:5:5:5 at 1250°C to obtain an alloy, which was crushed and then ball-milled to 3 microns to obtain deoxidizer powder.

[0027] (3) Production application: The recycled copper is sorted, 120 tons are weighed and added to the smelting furnace for heating and melting at a temperature of 1250°C. After sampling, the copper content is determined to be 98.0% using a spectrometer. Oxygen is introduced into the melt using an oxygenating tube for 120 minutes at a rate of 7 cubic meters per minute. 480 kg of deoxidizer powder is weighed and mixed into the oxygen in the oxygenating tube, and introduced into the melt for purification and deoxidation, with a spraying time of 60 minutes. Natural gas is introduced into the melt for reduction treatment, with a flow time of 120 minutes at a rate of 6 cubic meters per minute. The oxygen content in the melt is measured to be 0.05%. 60 kg of deoxidizer powder is weighed and mixed into natural gas, and introduced into the melt for reduction, with a spraying time of 60 minutes. After removing the scum on the surface, it is covered with charcoal and allowed to stand for 20 minutes. The final copper rod product is obtained by continuous casting and rolling.

[0028] Example 2

[0029] (1) Preparation of impurity remover: Silica powder, sodium sulfide, calcium carbonate, chromium carbonate, calcium chloride, and sodium fluoroaluminate were uniformly mixed in a mass ratio of 51:19:15:4:6:5 to prepare an impurity remover, and the mixture was ball-milled to 3 μm to obtain an impurity remover powder.

[0030] (2) Preparation of deoxidizer: pure copper, pure magnesium, pure phosphorus, pure calcium, pure cerium and pure lanthanum were smelted at a mass ratio of 50:19:16:4:5:6 at 1260°C to obtain an alloy, which was crushed and then ball-milled to 3 microns to obtain deoxidizer powder.

[0031] (3) Production application: The recycled copper is sorted, 120 tons are weighed and added to the smelting furnace for heating and melting at a temperature of 1260°C. After sampling, the copper content is determined to be 98.0% using a spectrometer. Oxygen is introduced into the melt using an oxygenating tube for 125 minutes at a rate of 7.2 cubic meters per minute. 475 kg of deoxidizer powder is weighed and mixed into the oxygen in the oxygenating tube, and introduced into the melt for purification and deoxidation, with a spraying time of 62 minutes. Natural gas is introduced into the melt for reduction treatment, with a injection time of 128 minutes at a rate of 6.1 cubic meters per minute. The oxygen content in the melt is measured to be 0.05%. 60 kg of deoxidizer powder is weighed and mixed into natural gas, and introduced into the melt for reduction, with a spraying time of 62 minutes. After removing the scum on the surface, it is covered with charcoal and allowed to stand for 25 minutes. The final copper rod product is obtained by continuous casting and rolling.

[0032] Example 3

[0033] Compared with Example 1, the weight of the impurity remover is 576 kg, the spraying time is 70 minutes, and the other steps are exactly the same.

[0034] Example 4

[0035] Compared with Example 1, the weight of the impurity remover is 384 kg, the spraying time is 35 minutes, and the other steps are exactly the same.

[0036] Example 5

[0037] Compared with Example 1, the weight of the deoxidizer is 72 kg, the spraying time is 70 minutes, and the other steps are exactly the same.

[0038] Example 6

[0039] Compared with Example 1, the weight of the deoxidizer is 48 kg, the spraying time is 35 minutes, and the other steps are exactly the same.

[0040] Example 7

[0041] Compared with Example 1, the time for introducing oxygen was 144 minutes, the time for introducing natural gas was 144 minutes, and the other steps were exactly the same.

[0042] Example 8

[0043] Compared with Example 1, the time for introducing oxygen was 96 minutes, the time for introducing natural gas was 96 minutes, and the other steps were exactly the same.

[0044] Comparative Example 1

[0045] The recycled copper is sorted, weighed, and 120 tons are added to a smelting furnace for melting at 1250°C. Samples are taken and the copper content is determined to be 98.0% using a spectrometer. Oxygen is introduced into the melt using an oxygen injection tube for 240 minutes at a rate of 7 cubic meters per minute. Natural gas is then introduced into the melt for a reduction treatment for 240 minutes at a rate of 6 cubic meters per minute. After removing surface scum, the melt is covered with charcoal and allowed to rest for 20 minutes. Continuous casting and rolling are then used to produce the final copper rod product.

[0046] Comparative Example 2

[0047] (1) Preparation of impurity remover: Silica powder, sodium sulfide, calcium carbonate, chromium carbonate, calcium chloride, and sodium fluoroaluminate were uniformly mixed in a mass ratio of 50:20:15:5:5:5 to prepare an impurity remover, and the mixture was ball-milled to 3 μm to obtain an impurity remover powder.

[0048] (2) Production application: The recycled copper is sorted, 120 tons are weighed and added to the smelting furnace for heating and melting at a temperature of 1250°C. After sampling, the copper content is determined to be 98.0% using a spectrometer. Oxygen is introduced into the melt using an oxygenating tube for 120 minutes at a rate of 7 cubic meters per minute. 480 kg of impurity remover powder is weighed and mixed into the oxygen in the oxygenating tube, and introduced into the melt for purification and impurity removal. The injection time is 60 minutes. Natural gas is introduced into the melt for reduction treatment. The injection time is 240 minutes at a rate of 6 cubic meters per minute. After removing the scum on the surface, it is covered with charcoal and allowed to stand for 20 minutes. The final copper rod product is obtained by continuous casting and rolling.

[0049] Comparative Example 3

[0050] (1) Preparation of deoxidizer: pure copper, pure magnesium, pure phosphorus, pure calcium, pure cerium, and pure lanthanum were smelted at a mass ratio of 50:20:15:5:5:5 at 1250°C to obtain an alloy, which was crushed and then ball-milled to 3 microns to obtain deoxidizer powder.

[0051] (2) Production application: The recycled copper is sorted, weighed 120 tons and added to the smelting furnace for heating and melting at a temperature of 1250°C. After sampling, the copper content is determined to be 98.0% using a spectrometer. Oxygen is introduced into the melt using an oxygenating tube for 240 minutes at a rate of 7 cubic meters per minute. Natural gas is introduced into the melt for reduction treatment for 120 minutes at a rate of 6 cubic meters per minute. The oxygen content in the melt is measured to be 0.05%. 60 kg of deoxidizer powder is weighed and mixed into the natural gas, and then introduced into the melt for reduction. The spraying time is 60 minutes. After removing the scum on the surface, it is covered with charcoal and allowed to stand for 20 minutes. The final copper rod product is obtained by continuous casting and rolling.

[0052] Table 1 is a table of copper rod product parameters obtained in Examples and Comparative Examples.

[0053] Table 1 Parameters of comparative examples and embodiments

[0054]

[0055] The performance tests of the products obtained in the above examples and comparative examples are shown in Table 2 below:

[0056] Table 2 Comparison of product performance between comparative example and embodiment

[0057]

[0058] As can be known from the performance comparison of embodiment and comparative example, the impurity remover of the present invention's design can effectively remove the impurity elements in the copper liquid. The main reason is that in the oxygen process, the impurity elements and oxygen generation oxidation reaction form oxide, which is suspended in the copper liquid. When the oxide concentration is too high, the generation of oxidation reaction can be suppressed, reducing the effect of oxidative impurity removal. Adding tiny impurity remover particles easily forms a bulky oxide slag with oxide polymerization and floats to the copper liquid surface, quickly reducing the concentration of suspended oxides therein, improving the effect of oxidative impurity removal, and reducing the content of impurity elements. The oxygen remover of the present invention's design can effectively reduce the oxygen content in the copper liquid. The main reason is that tiny oxygen remover particles sneak into the copper liquid by natural gas, and the active metals such as magnesium, phosphorus, calcium, cerium, lanthanum in the oxygen remover form oxide with oxygen generation oxidation reaction quickly, and efficiently reduce the oxygen content in the copper liquid. Along with the addition of impurity remover increases gradually, the impurity removal effect does not change substantially, but can improve production cost. Excessive addition of oxygen remover easily causes the element contents such as magnesium, phosphorus, calcium, cerium, lanthanum to increase, is dissolved in the copper liquid and forms solid solution, reduces the copper content of copper rod, affects the electrical conductivity of copper rod.Need in time to adjust the input amount of impurity remover and oxygen remover according to the copper content and oxygen content in the copper liquid, control production cost and copper liquid quality.From the production efficiency comparison of embodiment and comparative example, it can be known that the copper liquid redox duration of embodiment 1 is 360 minutes, and the copper liquid redox duration of comparative example 1 is 480 minutes, and production efficiency improves 25%.By performance and production efficiency contrast, the impurity remover of the present invention's design can remove the foreign matter content in the copper liquid fast, and oxygen remover can reduce the oxygen content in the copper liquid fast, can promote the performance index of copper liquid, can also improve production efficiency.

Claims

1. A method for preparing oxygen-free copper by efficiently removing impurities from recycled copper, characterized in that: The following steps are involved: S1. The recycled copper is heated and melted to obtain a recycled copper melt, and the copper content is determined by spectral analysis as n, where n is expressed in wt.%; S2. Oxygen is continuously introduced into the recycled copper melt for a preset time. During the oxygenation process, the impurity remover powder is weighed according to the impurity element content obtained in step S1, and the impurity remover powder is sprayed into the furnace together with oxygen to react with impurities in the melt to obtain a regenerated copper melt after impurity removal; S3. After the impurities are removed, the regenerated copper melt is continuously fed with natural gas for a preset time, and the oxygen content in the melt is measured (s), where s is expressed in wt.%. The deoxidizer powder is weighed according to the oxygen content, and the deoxidizer powder is sprayed into the furnace using natural gas to react with oxygen in the melt to obtain a deoxidized regenerated copper melt. S4. The deoxidized regenerated copper melt is allowed to stand, slag in the melt is removed, and the melt is cast to obtain an oxygen-free copper product.

2. The method for preparing oxygen-free copper by efficiently removing impurities from recycled copper according to claim 1, characterized in that: In step S1, the heating and melting temperature is 1200-1300° C.; the impurity elements include Zn, Fe, Ni, Sn, Mn, Cr, and Mg.

3. The method for preparing oxygen-free copper by efficiently removing impurities from recycled copper according to claim 1, characterized in that: In step S2, the oxygen is introduced for a time of 0.8-1.2 minutes per ton, and the oxygen introduction rate is 5-9 cubic meters per minute based on the weight of the recycled copper raw material.

4. The method for preparing oxygen-free copper by efficiently removing impurities from recycled copper according to claim 1, wherein: The impurity remover powder is a mixture of silica powder, sodium sulfide, calcium carbonate, chromium carbonate, calcium chloride and sodium fluoroaluminate; wherein the ratio of silica powder, sodium sulfide, calcium carbonate, chromium carbonate and calcium chloride is: 40-60: 10-30: 10-20: 4-6: 4-6: 4-6; and the particle size of the impurity remover powder is 2 to 4 microns.

5. The method for preparing oxygen-free copper by efficiently removing impurities from recycled copper according to claim 1, characterized in that: The calculation formula for the injection weight of the impurity remover powder is: (0.8-1.2)*(1-100n)*2T / 1000, wherein n is the copper content; T is the melt weight in tons; and the injection time of the impurity remover powder is 20 to 80 minutes.

6. The method for preparing oxygen-free copper by efficiently removing impurities from recycled copper according to claim 1, characterized in that: In step S3, the time for introducing natural gas is 0.8-1.2 minutes per ton, and the speed of introducing natural gas is 4-8 cubic meters per minute based on the weight of the recycled copper raw material.

7. The method for preparing oxygen-free copper by efficiently removing impurities from recycled copper according to claim 1, characterized in that: The preparation method of the deoxidizer powder is as follows: copper, magnesium, phosphorus, calcium, cerium and lanthanum are smelted in a mass ratio of 40-60:10-30:10-30:4-6:4-6 to obtain an alloy, and then the alloy is ball-milled to a particle size of 2 to 4 microns to obtain the deoxidizer powder.

8. The method for preparing oxygen-free copper by efficiently removing impurities from recycled copper according to claim 1, characterized in that: The injection weight of the deoxidizer powder is calculated as follows: (800-1200)*s*T, wherein s is the oxygen content; T is the melt weight in tons; and the injection time of the deoxidizer powder is 20 to 80 minutes.

9. The method for preparing oxygen-free copper by efficiently removing impurities from recycled copper according to claim 1, characterized in that: In step S4, the standing time is 15 to 30 minutes.

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