Preparation method of high-purity copper
Through the crucible heating system and seed rod lifting method, combined with reverse rotation and inert gas protection, the problems of pollution, low yield and high cost in the preparation of high-purity copper are solved, and efficient and low-cost high-purity copper production is achieved.
Patent Information
- Application Number
- CN202510651748.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-20
- Publication Date
- 2025-08-19
AI Technical Summary
The existing high-purity copper preparation technology has problems such as high pollution, low yield and high preparation cost.
The crucible heating system and seed rod lifting method are used to rotate the seed rod and the crucible in reverse direction, combined with inert gas protection, and the copper melt is lifted and impurity separation is achieved through crystal extraction, shoulder release, equal diameter growth and finishing operations.
It has achieved green and clean production of high-purity copper, significantly shortened preparation time, reduced energy consumption and equipment loss costs, improved copper purity, adapted to large-scale production needs, and had high impurity removal efficiency.
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Figure CN120505694A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of high-purity copper processing, in particular to a method for preparing high-purity copper. Background Art
[0002] High-purity copper is a key material in the electronics, energy, aerospace, and other fields. In the electronics industry, it is used in semiconductor lead frames, high-frequency transmission lines, and other applications, facilitating advanced chip packaging and signal transmission. In the energy and cutting-edge technology sectors, it can be used as a stabilizing material for superconducting magnets in nuclear fusion devices and as a heat dissipation material for quantum chips. Existing technologies for producing high-purity copper primarily include electrolytic copper, zone melting, and electron beam processing.
[0003] The main principle of electrolytic copper is that under the action of direct current, the copper on the anode enters the electrolyte in ionic state. Under the action of the electric field force, the copper ions migrate to the cathode, a reduction reaction occurs, and cathode copper is precipitated. Due to the potential difference between various elements, impurity ions can be separated. This method requires the use of a large amount of strong acid solutions such as sulfuric acid and nitric acid, which has great pollution to the environment and there is a problem that the impurity metals cannot be separated.
[0004] The zone melting method primarily exploits the difference in solubility of impurities in the solid and liquid phases to migrate impurity ions and thereby purify metallic copper. However, the main drawback is that obtaining high-purity copper requires multiple zone melting cycles, which can create a risk of melting the crucible. Furthermore, the production output is limited.
[0005] The electron beam method primarily uses a high-energy electron beam emitted from an electron gun to bombard crude copper in a high vacuum environment. The highly concentrated energy of the electron beam causes the crude copper to melt and evaporate rapidly. Impurities, due to their different vapor pressures, separate from the copper during the melting and evaporation process. The copper vapor condenses and crystallizes on a condenser, producing high-purity copper. However, the disadvantages are the high cost of the equipment and the maintenance required for the electron gun, resulting in high production costs.
[0006] Therefore, those skilled in the art are in urgent need of developing a method for preparing high-purity copper. Summary of the Invention
[0007] The purpose of the present invention is to solve the shortcomings of the existing technology, such as large pollution, low output and high preparation cost, and to propose a method for preparing high-purity copper.
[0008] In order to achieve the above object, the present invention adopts the following technical solution: a method for preparing high-purity copper, comprising the following steps: S1. Assembling a temperature field: configuring a crucible for accommodating copper melt, with insulation material and a heating system sequentially arranged on the outside of the crucible, and a seed crystal rod arranged above the crucible; S2, adding raw materials: adding copper raw materials into the crucible; S3, heating and melting materials: starting the heating system to melt the copper raw material to form a copper melt, and keeping the temperature of the copper melt higher than its melting point; S4. Immerse the seed crystal into the copper melt through the seed crystal rod, and perform seeding, shouldering, equal diameter growth and finishing operations in sequence. During the operation, the rotation speed of the seed crystal rod is 5-15 rpm, the rotation speed of the crucible is 5-15 rpm, the rotation direction of the seed crystal rod is opposite to the rotation direction of the crucible, and the pulling speed is 1-5 mm / min.
[0009] Preferably, in step S1, the heating system includes a heating coil arranged around the crucible, the crucible is a molybdenum crucible or a tungsten crucible, the insulation material is zirconia, and an alumina pot is provided on the outside of the zirconia.
[0010] Preferably, in step S2, the purity of the copper raw material is not less than 99%.
[0011] Preferably, in step S4, an inert gas is introduced into the crucible and the copper raw material during the isodiameter growth process, and the inert gas is argon.
[0012] Preferably, in step S4, the seed crystal is a high-purity copper seed crystal.
[0013] Preferably, in step S4, a rotating motor for rotating the crucible is provided at the bottom, the output end of the rotating motor passes through the insulation material in sequence and is connected to the crucible, and a lifting assembly is provided at the bottom of the rotating motor, the lifting assembly includes a lifting rod, and the height of the crucible can be adjusted to a suitable temperature field by adjusting the height of the crucible.
[0014] Preferably, in step S4, the seeding includes controlling the seed rod to move downward to establish a solid-liquid interface; the shouldering includes expanding the crystal diameter to a target size and pulling it; the isodiametric growth includes maintaining a constant speed of pulling; and the finishing includes gradually reducing the crystal diameter until it separates from the melt.
[0015] Compared with the prior art, the present invention has the following beneficial effects: 1. Compared with traditional methods, this process can significantly improve copper purity with only one purification, significantly shortening preparation time and reducing energy consumption and equipment loss costs; at the same time, copper output can be flexibly adjusted according to the specifications of the crucible and pulling furnace to adapt to large-scale production needs, effectively solving the problem of high cost and small preparation volume of high-purity copper.
[0016] 2. The preparation of high-purity copper by the Czochralski method does not require the use of corrosive reagents such as strong acids. No harmful waste liquid is discharged during the production process, eliminating chemical pollution at the source, achieving green and clean production, and reducing environmental protection management costs and safety risks.
[0017] 3. During the crystallization process, the segregation effect is used to naturally separate impurities. At the same time, by precisely controlling the rotation speed of the seed crystal rod and crucible, most impurities are forced out by centrifugal action. The dual mechanisms work together to ensure efficient impurity removal.
[0018] Fourth, seed crystals are introduced as crystallization templates, and subsequent atoms grow strictly according to the order of the seed crystal atoms, forming a highly ordered single crystal structure; and the reverse rotation of the seed crystal rod and the crucible is the key to improving purity. On this basis, increasing the rotation speed can further enhance the purification effect. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] Figure 1 It is a structural diagram of the production equipment of the present invention. DETAILED DESCRIPTION
[0020] The present invention will be further described below with reference to specific embodiments. The illustrative embodiments and descriptions of the present invention are intended to explain the present invention but are not intended to limit the present invention.
[0021] Example 1: Molybdenum metal was used as the crucible 2, and 99% copper was selected as the raw material. Zirconia 6 was used as the insulation material 3, and an alumina pot 7 was installed outside the zirconia 6. The seed crystal rod 11 rotated clockwise at 10 rpm, while the crucible 2 was rotated counterclockwise by a rotary motor 5 at 8 rpm. The seed crystal rod 1 and crucible 2 rotated in opposite directions. The crystal was pulled at a speed of 2 mm / min, resulting in a high-purity copper rod with a length of 250 mm and a diameter of 120 mm. The copper purity was tested to be 6.5N.
[0022] Example 2: Tungsten metal was used as crucible 2, and 99% copper was selected as the raw material. The crucible was heated by a heating coil 4, and zirconia 6 and insulation material 3 were used. The zirconia 6 was equipped with an alumina pot 7. The seed crystal rod 1 rotated clockwise at 10 rpm, while the crucible 2 was rotated counterclockwise by a rotary motor 5 at 8 rpm. The seed crystal rod 1 and crucible 2 rotated in opposite directions. The crystal was pulled at a speed of 2 mm / min. A high-purity copper rod with a length of 250 mm and a diameter of 117 mm was obtained. The copper purity was tested to be 6.5N.
[0023] Comparative Example 1: Molybdenum metal was used as crucible 2, and 99% copper was selected as the raw material. Zirconia 6 was used as insulation material 3, and an alumina pot 7 was installed outside the zirconia 6. Seed crystal rod 1 rotated clockwise at 10 rpm, while crucible 2 was rotated clockwise at 8 rpm by motor 5. Seed crystal rod 1 and crucible 2 rotated in the same direction. The crystal was pulled at a speed of 2 mm / min. A high-purity copper rod with a length of 238 mm and a diameter of 121 mm was obtained. The copper purity was tested to be 6N.
[0024] Comparative Example 2: Molybdenum metal was used as crucible 2, and 99% copper was selected as the raw material. Zirconia 6 was used as insulation material 3, and an alumina pot 7 was installed outside the zirconia 6. Seed crystal rod 1 rotated clockwise at 5 rpm, while crucible 2 was rotated counterclockwise at 5 rpm by motor 5. The seed crystal rod 1 and crucible 2 rotated in opposite directions. The crystal was pulled at a speed of 2 mm / min, resulting in a copper rod with a length of 242 mm and a diameter of 119 mm. The copper purity was tested to be 6.2N.
[0025] The direction of rotation is a key factor affecting purity. The counter-rotation of the seed rod 1 and the crucible 2 can significantly improve the purity of the copper rod. The rotation speed has an auxiliary effect on purity. Under the premise of counter-rotation, a higher rotation speed can further improve purity.
[0026] The technical solution of the present invention is not limited to the above-mentioned specific embodiments. Any technical variations made according to the technical solution of the present invention fall within the protection scope of the present invention.
Claims
1. A method for preparing high-purity copper, characterized in that: The following steps are involved: S1. Assembling a temperature field: configuring a crucible for accommodating copper melt, with insulation material and a heating system sequentially arranged on the outside of the crucible, and a seed crystal rod arranged above the crucible; S2, adding raw materials: adding copper raw materials into the crucible; S3, heating and melting materials: starting the heating system to melt the copper raw material to form a copper melt, and keeping the temperature of the copper melt higher than its melting point; S4. Immerse the seed crystal into the copper melt through the seed crystal rod, and perform seeding, shouldering, equal diameter growth and finishing operations in sequence. During the operation, the rotation speed of the seed crystal rod is 5-15 rpm, the rotation speed of the crucible is 5-15 rpm, the rotation direction of the seed crystal rod is opposite to the rotation direction of the crucible, and the pulling speed is 1-5 mm / min.
2. The method for preparing high-purity copper according to claim 1, wherein: In step S1, the heating system includes a heating coil arranged around a crucible, the crucible is a molybdenum crucible or a tungsten crucible, the insulation material is zirconia, and an alumina pot is arranged outside the zirconia.
3. The method for preparing high-purity copper according to claim 1, wherein: In step S2, the purity of the copper raw material is not less than 99%.
4. The method for preparing high-purity copper according to claim 1, wherein: In step S4, an inert gas is introduced into the crucible and the copper raw material during the isodiameter growth process, wherein the inert gas is argon.
5. The method for preparing high-purity copper according to claim 1, wherein: In step S4, the seed crystal is a high-purity copper seed crystal.
6. The method for preparing high-purity copper according to claim 1, wherein: In step S4, a rotating motor for rotating the crucible is provided at the bottom of the crucible, and a lifting assembly is provided at the bottom of the rotating motor, wherein the lifting assembly includes a lifting rod.