Preparation method and device of single crystal copper rod

Abstract

The invention relates to a preparation method and device of a single crystal copper rod, and belongs to the technical field of copper processing. The method comprises the following steps: by taking a waste copper plate as a raw material, heating and melting the pretreated waste copper plate to obtain copper liquid; rare earth is added into the obtained copper liquid, and inert gas is continuously introduced for vacuum refining treatment; the refined copper liquid is subjected to cooling treatment; and the cooled copper liquid is cooled and crystallized, and the single crystal copper is obtained through continuous traction. The rare earth and impurity elements (such as lead, arsenic, oxygen, sulfur and the like) in the copper liquid form a high-melting-point compound, and in the refining process, inert gas is continuously introduced, so that the high-melting-point compound in the copper liquid floats or volatilizes to be removed; the production device of the single crystal copper rod is simpler, a water cooling device does not need to be additionally arranged below the casting opening to cool the copper rod, and the later maintenance cost is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of copper processing, and in particular to a method and a device for preparing a single crystal copper rod. Background Art

[0002] Single crystal copper reduces the reflection and scattering of electrons passing through the grain boundary, avoiding the increase of resistivity and energy loss, and therefore has excellent electrical properties. According to the literature (Cho, Lee et al. 2010), the conductivity of single crystal copper is 9% higher than that of oxygen-free copper; in addition, single crystal copper also has excellent corrosion resistance and good plastic processing properties, and has been widely used in communications (mainly concentrated in audio speakers, power cords, audio cables, microphone cables, HDMI cables, and various connectors, etc.), electronic packaging (the connection between chips and external leads in large-scale integrated circuits), and other fields.

[0003] As early as 1978, Ohno Atsumi (Ohno) of Chiba Institute of Technology in Japan conceived a new directional casting method Ohno Continuous Casting (OCC method for short), the core of which is to avoid lateral heat dissipation, maintain a very high temperature gradient in the pulling direction, and ensure that the solidification interface is convex to the liquid phase. At present, the existing technology usually uses high-purity copper as raw material to produce single crystal copper rods, and the raw material price is high. The existing vacuum heat-inducing continuous casting requires heating and insulation of the crystallizer to obtain a directional solidification structure. The solid-liquid interface is usually located at the outlet of the crystallizer, and only relies on the surface tension of the copper melt to prevent leakage. In actual production, accidents such as freezing and leakage are prone to occur. In addition, the outlet temperature of the casting can be as high as 1000℃, and the copper rod is easily oxidized at this temperature. Therefore, when the protective gas is introduced, a water cooling device is also required under the casting mouth to cool the copper rod. The existing bottom heat-inducing continuous casting device is relatively complex and has high maintenance costs.

[0004] Therefore, it is very necessary to improve the preparation process and equipment of single crystal copper rod. Summary of the invention

[0005] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a method and device for preparing a single crystal copper rod.

[0006] To achieve the above object, the technical solution adopted by the present invention is:

[0007] In a first aspect, the present invention provides a method for preparing a single crystal copper rod, comprising the following steps:

[0008] S1, after shearing, cleaning and drying the waste copper plate, heating and melting it to obtain copper liquid;

[0009] S2, adding rare earth to the copper liquid obtained in step S1, and continuously introducing inert gas for vacuum refining treatment;

[0010] S3, cooling the copper solution after being processed in step S2;

[0011] S4, cooling and crystallizing the copper liquid treated in step S3, and obtaining the single crystal copper rod by continuous pulling.

[0012] Preferably, in step S1, the waste copper plate is a 4N cathode copper plate, and the vacuum degree of the heating and melting is 0.01-0.05Pa.

[0013] Preferably, in step S2, the inert gas flow rate is 1-5 L / min, the vacuum degree of the vacuum refining is not greater than 10 Pa, the vacuum refining temperature is 1300-1400° C., and the vacuum refining time is 20-120 min.

[0014] Preferably, in step S2, the rare earth includes yttrium, and the amount of the rare earth added is

[0015] Preferably, step S3 specifically comprises: cooling the copper liquid treated in step S2 to 1250-1350°C, increasing the pressure to 0.1×10 5 ~0.11×10 5 Pa.

[0016] Preferably, in step S4, the pulling speed is 0.01-0.5 mm / s.

[0017] In the second aspect, the present invention provides a preparation device for a single crystal copper rod, comprising a vacuum downward-drawing continuous casting furnace and a pulling device, wherein a crucible and a crystallizer are arranged in the chamber of the vacuum downward-drawing continuous casting furnace, a feeding port is arranged at the top of the vacuum downward-drawing continuous casting furnace, an exhaust port is arranged at the side wall of the vacuum downward-drawing continuous casting furnace, a casting port is arranged at the bottom of the vacuum downward-drawing continuous casting furnace, the crucible is a structure with a hollow interior and openings at both ends, a vent is arranged at the bottom of the crucible, and the bottom opening of the crucible, the crystallizer and the casting port of the vacuum downward-drawing continuous casting furnace are connected in sequence.

[0018] Preferably, an induction heating coil is arranged outside the crucible, and the crucible is made of graphite.

[0019] Preferably, the crystallizer is a tubular structure, the material of the crystallizer is graphite, and the crystallizer includes a heat preservation part, a connecting part and a cooling part which are sequentially connected from top to bottom, and the wall thickness of the heat preservation part and the wall thickness of the cooling part are both greater than the wall thickness of the connecting part.

[0020] Further preferably, the outer shell of the heat-insulating part is provided with a heat-insulating sleeve, and the material of the heat-insulating sleeve is alumina.

[0021] Further preferably, the outer sleeve of the connection part is provided with a heat insulating sleeve, the material of the heat insulating sleeve is aluminum oxide or magnesium oxide, the upper end of the heat insulating sleeve is in contact with the heat preservation part, and the lower end of the heat insulating sleeve is in contact with the cooling part.

[0022] Further preferably, the cooling unit is outer-coated with a water cooling jacket.

[0023] Preferably, a feeding device is provided at the feeding port of the vacuum down-draw continuous casting furnace, the discharge port of the feeding device is located above the crucible, and the feeding device is used to feed the crucible.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] The invention uses waste copper plates as raw materials, forms high-melting-point compounds with rare earth and impurity elements (such as lead, arsenic, oxygen, sulfur, etc.) in copper liquid, and continuously introduces inert gas during the refining process to make the high-melting-point compounds in the copper liquid float or volatilize and remove;

[0026] The production device of the single crystal copper rod adopted by the present invention is simpler, and no additional water cooling device is needed under the casting nozzle to cool the copper rod, thereby reducing the subsequent maintenance cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 A schematic structural diagram of a device for preparing a single crystal copper rod provided by the present invention;

[0028] Figure 2 A metallographic image of a cross section of a single crystal copper rod provided in Example 1 of the present invention;

[0029] Figure 3 The XRD test result of the cross section of the single crystal copper rod provided in Example 1 of the present invention;

[0030] Figure 4 A metallographic image of a cross section of a single crystal copper rod provided in Example 2 of the present invention;

[0031] Figure 5 XRD test results of the cross section of the single crystal copper rod provided in Example 2 of the present invention;

[0032] Figure 6 A metallographic image of a cross section of a single crystal copper rod provided in Example 3 of the present invention;

[0033] Figure 7 The XRD test result of the cross section of the single crystal copper rod provided in Example 3 of the present invention;

[0034] Figure 8A metallographic image of a cross section of a single crystal copper rod provided in Example 4 of the present invention;

[0035] Fig. 9 This is a metallographic image of the cross section of a single crystal copper rod provided in Example 5 of the present invention. DETAILED DESCRIPTION

[0036] In order to better illustrate the purpose, technical solutions and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.

[0037] In a first aspect, the present invention provides a method for preparing a single crystal copper rod, comprising the following steps:

[0038] S1, after shearing, cleaning and drying the waste copper plate, heating and melting it to obtain copper liquid;

[0039] S2, adding rare earth to the copper liquid obtained in step S1, and continuously introducing inert gas for vacuum refining treatment;

[0040] S3, cooling the copper solution after being processed in step S2;

[0041] S4, cooling and crystallizing the copper liquid treated in step S3, and obtaining the single crystal copper rod by continuous pulling.

[0042] The invention uses waste copper plates as raw materials, forms high-melting-point compounds through rare earth and impurity elements (such as lead, arsenic, oxygen, sulfur, etc.) in copper liquid, and in the refining process, continuously introduces inert gas to make the high-melting-point compounds in the copper liquid float or volatilize and remove.

[0043] In one embodiment, in step S1, the waste copper plate is a 4N cathode copper plate, and the vacuum degree of the heating and melting is 0.01-0.05Pa.

[0044] In one embodiment, in step S2, the inert gas flow rate is 1-5 L / min, the vacuum degree of the vacuum refining is not greater than 10 Pa, the temperature of the vacuum refining is 1300-1400° C., and the time of the vacuum refining is 20-120 min.

[0045] In one embodiment, in step S2, the rare earth includes yttrium, and the amount of rare earth added is 1:1 of the mass of the copper liquid.

[0046] In one embodiment, step S3 specifically includes: cooling the copper liquid treated in step S2 to 1250-1350°C, increasing the pressure to 0.1×10 5 ~0.11×10 5 Pa.

[0047] In one embodiment, in step S4, the pulling speed is 0.01-0.5 mm / s.

[0048] like Figure 1 As shown, in the second aspect, the present invention provides a single crystal copper rod preparation device. In the present invention, the single crystal copper rod preparation method described in the first aspect is implemented by the single crystal copper rod preparation device described in the second aspect.

[0049] The single crystal copper rod preparation device comprises a vacuum down-drawing continuous casting furnace 1 and a pulling device 4, a crucible 2 and a crystallizer 3 are arranged in the chamber of the vacuum down-drawing continuous casting furnace 1, a feeding port is arranged at the top of the vacuum down-drawing continuous casting furnace 1, a suction port 11 is arranged at the side wall of the vacuum down-drawing continuous casting furnace, a casting port is arranged at the bottom of the vacuum down-drawing continuous casting furnace, the crucible 2 is a structure with a hollow interior and openings at both ends, a vent 21 is arranged at the bottom of the crucible 2, and the bottom opening of the crucible 2, the crystallizer 3 and the bottom casting port of the vacuum down-drawing continuous casting furnace 1 are connected in sequence.

[0050] An induction heating coil is arranged outside the crucible 2 to heat the material in the crucible 2; the crucible 2 is made of graphite. The vent 21 is connected to the gas supply equipment outside the vacuum downcasting furnace 1 through a pipeline. The exhaust port 11 is connected to an external exhaust fan through a pipeline.

[0051] In one embodiment, the crystallizer 3 is a tubular structure, the material of the crystallizer 3 is graphite, and the crystallizer 3 includes a heat preservation part 31, a connecting part 32 and a cooling part 33 which are connected in sequence, and the wall thickness of the heat preservation part 31 and the wall thickness of the cooling part 33 are both greater than the wall thickness of the connecting part 32; the heat conduction between the heat preservation part 31 and the cooling part 33 can be effectively reduced, so that the copper liquid entering the crystallizer 3 obtains a larger temperature gradient, and this temperature gradient is adaptive and does not require manual control, making the production process simpler and more reliable.

[0052] Specifically, the central axis of the heat preservation part 31, the central axis of the connecting part 32, and the central axis of the cooling part 33 are on the same straight line, and the inner diameters of the heat preservation part 31, the inner diameters of the connecting part 32, and the inner diameters of the cooling part 33 are the same. Those skilled in the art can design the inner diameters of the heat preservation part 31, the inner diameters of the connecting part 32, and the inner diameters of the cooling part 33 according to actual needs.

[0053] Specifically, the wall thickness of the connection portion 32 is 1 to 1.5 mm, and the height h of the connection portion 32 is 1 to 2 mm.

[0054] The wall thickness of the heat-insulating portion 31 is d 1 , the wall thickness of the connecting portion 32 is d 2 , the wall thickness of the cooling part 33 is d 3 , d 1 :d 2 :d 3Preferably the following conditions are met: 1 :d 2 :d 3 =(2~5):1:(1.5~4).

[0055] Specifically, the heat-insulating portion 31 is covered with a heat-insulating sleeve 5 , and the heat-insulating sleeve 5 is made of alumina.

[0056] Specifically, the connecting portion 32 is covered with a heat insulating sleeve 6 , which is made of aluminum oxide or magnesium oxide. The upper end of the heat insulating sleeve 6 contacts the heat preservation portion 31 , and the lower end of the heat insulating sleeve 6 contacts the cooling portion 33 .

[0057] Specifically, the cooling part 33 is outerly provided with a water cooling jacket 7, and the water cooling jacket 7 has a cooling water inlet and a cooling water outlet. The cooling water inlet is connected to the cooling water supply equipment outside the vacuum down-drawing continuous casting furnace 1 through a pipeline, and the pipeline connected to the cooling water outlet extends to the outside of the vacuum down-drawing continuous casting furnace 1.

[0058] Specifically, the heat-insulating portion 31 , the connecting portion 32 and the cooling portion 33 are integrally formed and connected.

[0059] In one embodiment, a feeding device 8 is provided at the feeding port of the vacuum down-draw continuous casting furnace 1 , and a discharge port of the feeding device 8 is located above the crucible 2 . The feeding device 8 is used to feed materials into the crucible 2 .

[0060] In one embodiment, a feeding device 10 is provided at the feeding port of the vacuum down-draw continuous casting furnace 1 , and a discharge port of the feeding device 10 corresponds to an opening of the crucible 2 .

[0061] The present invention provides the following examples and comparative examples to facilitate understanding of the present invention. The present invention provides these examples but is not intended to limit the scope of the claims.

[0062] Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the art.

[0063] The copper plate fragments in the following embodiments are prepared by the following method: a 4N cathode copper plate is cut into copper plate fragments of 100×400 mm, the copper plate fragments are placed in an ultrasonic cleaner, a cleaning solution is added until the copper plate fragments are submerged, ultrasonic cleaning is performed at 30° C. for 30 min, the surface of the copper plate fragments is scrubbed with a brush, and the cleaning solution remaining on the fragments is washed off with water; the copper plate fragments are placed in an ultrasonic cleaner, deionized water is added until the copper plate fragments are submerged, ultrasonic cleaning is performed at 30° C. for 30 min, the fragments are removed, the surface of the fragments is rinsed with deionized water, and then placed in a drying oven for drying for standby use.

[0064] The method of the following embodiment is implemented by a single crystal copper rod preparation device, such as Figure 1As shown, the preparation device of the single crystal copper rod includes a vacuum down-drawing continuous casting furnace 1 and a pulling device 4, a crucible 2 and a crystallizer 3 are arranged in the chamber of the vacuum down-drawing continuous casting furnace 1, a feeding port is arranged on the top of the vacuum down-drawing continuous casting furnace 1, an exhaust port 11 is arranged on the side wall of the vacuum down-drawing continuous casting furnace, a casting port is arranged on the bottom of the vacuum down-drawing continuous casting furnace, the crucible 2 is a structure with a hollow interior and openings at both ends, a vent 21 is arranged at the bottom of the crucible 2, the bottom opening of the crucible 2, the crystallizer 3 and the bottom casting port of the vacuum down-drawing continuous casting furnace 1 are connected in sequence; a feeding device 8 is arranged at the feeding port of the vacuum down-drawing continuous casting furnace 1, the discharge port of the feeding device 8 is located above the crucible 2, and the feeding device 8 is used to feed the crucible 2.

[0065] An induction heating coil is arranged outside the crucible 2 to heat the material in the crucible 2; the material of the crucible 2 is graphite. The air vent 21 is connected to the gas supply equipment outside the vacuum down-draw continuous casting furnace 1 through a pipeline. The exhaust port 11 is connected to the external exhaust fan through a pipeline; the crystallizer 3 is a tubular structure, and the material of the crystallizer 3 is graphite. The crystallizer 3 includes an insulation part 31, a connecting part 32 and a cooling part 33 which are sequentially connected from top to bottom; the insulation part 31, the connecting part 32 and the cooling part 33 are integrally formed and connected. The central axis of the insulation part 31, the central axis of the connecting part 32 and the central axis of the cooling part 33 are on the same straight line, and the inner diameter of the insulation part 31, the inner diameter of the connecting part 32 and the inner diameter of the cooling part 33 are the same; the wall thickness of the connecting part 32 is 1.2 mm, and the height of the connecting part 32 is 1.5 mm; the wall thickness of the insulation part 31 is d 1 , the wall thickness of the connecting portion 32 is d 2 , the wall thickness of the cooling part 33 is d 3 , d 1 :d 2 :d 3 Preferably the following conditions are met: 1 :d 2 :d 3 =3:1:2; the heat-insulating part 31 is provided with a heat-insulating sleeve 5, and the material of the heat-insulating sleeve 5 is alumina; the connecting part 32 is provided with a heat-insulating sleeve 6, and the material of the heat-insulating sleeve 6 is alumina, the upper end of the heat-insulating sleeve 6 is in contact with the heat-insulating part 31, and the lower end of the heat-insulating sleeve 6 is in contact with the cooling part 33; the cooling part 33 is provided with a water-cooling jacket 7, and the water-cooling jacket 7 has a cooling water inlet and a cooling water outlet, and the cooling water inlet is connected to the cooling water supply equipment outside the vacuum down-drawing continuous casting furnace 1 through a pipeline, and the pipeline connected to the cooling water outlet extends to the outside of the vacuum down-drawing continuous casting furnace 1.

[0066] Example 1

[0067] The present embodiment provides a method for preparing a single crystal copper rod, comprising the following steps:

[0068] S1, adding the dried copper plate fragments into the crucible 2, evacuating the air pressure in the vacuum downcasting furnace 1 to 0.01 Pa, heating to 1350° C., so that the copper plate fragments are completely melted into copper liquid;

[0069] S2. At 1350°C, add yttrium with a purity of 99.99% to the copper liquid obtained in step S1, and the amount of yttrium added is 10% of the mass of the copper liquid. Argon gas was continuously introduced from the vent 21 at the bottom of the crucible 2 at a flow rate of 2 L / min, the pressure in the vacuum downcasting furnace 1 was maintained at 10 Pa, and the vacuum refining treatment was performed for 30 minutes;

[0070] S3. After refining, the temperature of the copper liquid in the crucible 2 is constant at 1290°C, the pulling device 4 is started, and the pulling is performed at a rate of 0.2 mm / s. The copper liquid is introduced into the crystallizer 3 for directional solidification to a temperature not higher than 100°C, and a single crystal copper rod with a diameter of 12.5 mm is prepared. During the directional solidification process, the water inlet temperature of the water cooling jacket 7 is 25°C, the temperature difference between the water outlet temperature and the water inlet temperature is not greater than 5°C, and the water inlet flow rate is 22 L / min.

[0071] Example 2

[0072] The difference between this embodiment and embodiment 1 is that step S3 of this embodiment performs pulling at a rate of 0.5 mm / s.

[0073] Example 3

[0074] The present embodiment provides a method for preparing a single crystal copper rod, comprising the following steps:

[0075] S1, adding the dried copper plate fragments into the crucible 2, evacuating the air pressure in the vacuum downcasting furnace 1 to 0.01 Pa, heating to 1380° C., so that the copper plate fragments are completely melted into copper liquid;

[0076] S2. At 1380°C, add yttrium with a purity of 99.99% to the copper liquid obtained in step S1, and the amount of yttrium added is 1 / 100% of the mass of the copper liquid. Argon gas was continuously introduced from the vent 21 at the bottom of the crucible 2 at a flow rate of 2 L / min, the pressure in the vacuum downcasting furnace 1 was maintained at 10 Pa, and the vacuum refining treatment was performed for 60 minutes;

[0077] S3. After the refining is completed, the temperature of the copper liquid in the crucible 2 is kept constant at 1280°C, the pulling device 4 is started, and the pulling is performed at a rate of 0.1 mm / s, and the copper liquid is introduced into the crystallizer 3 for directional solidification to prepare a single crystal copper rod with a diameter of 12.5 mm. During the directional solidification process, the water inlet temperature of the water cooling jacket 7 is 25°C, the temperature difference between the water outlet temperature and the water inlet temperature is not greater than 5°C, and the water inlet flow rate is 22 L / min.

[0078] Example 4

[0079] The present embodiment provides a method for preparing a single crystal copper rod, comprising the following steps:

[0080] S1, adding the dried copper plate fragments into the crucible 2 of the vacuum down-drawing continuous casting furnace, evacuating the air pressure in the vacuum down-drawing continuous casting furnace to 0.01 Pa, heating to 1300 ° C, so that the copper plate fragments are completely melted into copper liquid;

[0081] S2. At 1300°C, add yttrium with a purity of 99.99% to the copper liquid obtained in step S1, and the amount of yttrium added is 10% of the mass of the copper liquid. Argon gas was continuously introduced from the vent 21 at the bottom of the crucible 2 at a flow rate of 1 L / min, the pressure in the vacuum downcasting furnace 1 was maintained at 10 Pa, and the vacuum refining treatment was performed for 120 min;

[0082] S3. After the refining is completed, the temperature of the copper liquid in the crucible 2 is kept constant at 1250°C, the pulling device 4 is started, and the pulling is performed at a rate of 0.5 mm / s, and the copper liquid is introduced into the crystallizer 3 for directional solidification to prepare a single crystal copper rod with a diameter of 12.5 mm. During the directional solidification process, the water inlet temperature of the water cooling jacket 7 is 25°C, the temperature difference between the water outlet temperature and the water inlet temperature is not greater than 5°C, and the water inlet flow rate is 22 L / min.

[0083] Example 5

[0084] The present embodiment provides a method for preparing a single crystal copper rod, comprising the following steps:

[0085] S1, adding the dried copper plate fragments into the crucible 2 of the vacuum down-drawing continuous casting furnace, evacuating the air pressure in the vacuum down-drawing continuous casting furnace to 0.01 Pa, heating to 1400° C., so that the copper plate fragments are completely melted into copper liquid;

[0086] S2. At 1400°C, add yttrium with a purity of 99.99% to the copper liquid obtained in step S1, and the amount of yttrium added is 10% of the mass of the copper liquid. Argon gas was continuously introduced from the vent 21 at the bottom of the crucible 2 at a flow rate of 5 L / min, the pressure in the vacuum downcasting furnace 1 was maintained at 10 Pa, and the vacuum refining treatment was performed for 20 minutes;

[0087] S3. After the refining is completed, the temperature of the copper liquid in the crucible 2 is kept constant at 1350°C, the pulling device 4 is started, and the pulling is performed at a rate of 0.5 mm / s, and the copper liquid is introduced into the crystallizer 3 for directional solidification to prepare a single crystal copper rod with a diameter of 12.5 mm. During the directional solidification process, the water inlet temperature of the water cooling jacket 7 is 25°C, the temperature difference between the water outlet temperature and the water inlet temperature is not greater than 5°C, and the water inlet flow rate is 22 L / min.

[0088] Comparative Example 1

[0089] The difference between this comparative example and Example 1 is that the crystallizer in the device adopted in the method of this comparative example is not provided with a connecting portion.

[0090] The single crystal copper rods obtained in the above embodiments and comparative examples were subjected to metallographic and XRD analysis and GDMS purity test. The results are shown in Table 1 and Figures 2 to 9 shown.

[0091] Table 1

[0092]

[0093] In the description of the present invention, it should also be noted that the terms "include", "have" and any variations thereof are intended to cover non-exclusive inclusions.

[0094] In the description of the present invention, it should also be noted that, unless otherwise clearly specified and limited, the term "connection" should be understood in a broad sense, for example, it can be direct connection or indirect connection through an intermediate medium.

[0095] For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0096] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A method for preparing a single crystal copper rod, characterized in that: The steps include: S1, heating and melting the pretreated waste copper plate to obtain copper liquid; S2, adding rare earth to the copper liquid obtained in step S1, and continuously introducing inert gas for vacuum refining treatment; S3, cooling the copper solution after being processed in step S2; S4, cooling and crystallizing the copper liquid treated in step S3, and obtaining the single crystal copper rod by continuous pulling.

2. The method for preparing a single crystal copper rod according to claim 1, characterized in that: In step S1, the waste copper plate is a 4N cathode copper plate, and the vacuum degree of the heating and melting is 0.01-0.05Pa.

3. The method for preparing a single crystal copper rod according to claim 1, characterized in that: In step S2, the inert gas flow rate is 1-5 L / min, the vacuum degree of the vacuum refining is not greater than 10 Pa, the vacuum refining temperature is 1300-1400° C., and the vacuum refining time is 20-120 min.

4. The method for preparing a single crystal copper rod according to claim 1, characterized in that: In step S2, the rare earth includes yttrium, and the amount of the rare earth added is 5. The method for preparing a single crystal copper rod according to claim 1, characterized in that: Step S3 specifically includes: cooling the copper liquid treated in step S2 to 1250-1350°C, increasing the pressure to 0.1×10 5 ~0.11×10 5 Pa.

6. The method for preparing a single crystal copper rod according to claim 1, characterized in that: In step S4, the pulling speed is 0.01-0.5 mm / s.

7. A device for preparing a single crystal copper rod, characterized in that: It includes a vacuum downward-drawing continuous casting furnace and a traction device, wherein a crucible and a crystallizer are arranged in the chamber of the vacuum downward-drawing continuous casting furnace, a feeding port is arranged on the top of the vacuum downward-drawing continuous casting furnace, an exhaust port is arranged on the side wall of the vacuum downward-drawing continuous casting furnace, a casting port is arranged on the bottom of the vacuum downward-drawing continuous casting furnace, the crucible is a structure with a hollow interior and openings at both ends, a vent is arranged at the bottom of the crucible, and the bottom opening of the crucible, the crystallizer and the casting port of the vacuum downward-drawing continuous casting furnace are connected in sequence.

8. The device for preparing a single crystal copper rod according to claim 7, characterized in that: The crystallizer is a tubular structure, and includes a heat preservation part, a connecting part and a cooling part which are sequentially connected from top to bottom. The wall thickness of the heat preservation part and the wall thickness of the cooling part are both greater than the wall thickness of the connecting part.

9. The device for preparing a single crystal copper rod according to claim 8, characterized in that: The outer jacket of the heat-insulating part is provided with a heat-insulating jacket, the outer jacket of the connecting part is provided with a heat-insulating jacket, and the outer jacket of the cooling part is provided with a water-cooling jacket.

10. The device for preparing a single crystal copper rod according to claim 7, characterized in that: A feeding device is arranged at the feeding port of the chamber, and a discharge port of the feeding device corresponds to the opening of the crucible.

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