Preparation method of large-size high-purity copper cast ingot

Abstract

The invention belongs to the technical field of metal material casting, and particularly relates to a preparation method of a large-specification high-purity copper cast ingot. The casting process adopting the short crystallizer and the annular water retaining device is provided, the water cooling effect is enhanced, the cast ingot is cooled more quickly, crystal grains are prevented from growing, and therefore the cast ingot with the uniform and fine structure is obtained. The preparation method of the cast ingot with the uniform and fine structure is good in operability, high in production efficiency and low in production cost, and industrial batch production can be achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of metal material casting, and specifically relates to a method for preparing a large-sized high-purity copper ingot, in particular to a method for preparing a large-sized high-purity copper ingot with a diameter greater than 260 mm. Background Art

[0002] Pure copper is widely used in all walks of life due to its good electrical conductivity, thermal conductivity and good corrosion resistance. With the rapid development of the semiconductor industry in recent years, large-scale high-purity copper rotating targets and high-purity copper superconducting materials have been continuously used, and their usage has increased year by year; the common feature of these materials is that they have very high requirements for comprehensive technical indicators, especially the requirements for internal organizational uniformity and zero tolerance for defects, which poses a severe challenge to products prepared by traditional process methods.

[0003] Research has found that in the preparation of this type of high-quality products, no matter what specifications and sizes, large-sized ingot blanks can be prepared by melting and casting, and then further processed into the required products; for example, large-sized high-purity copper rotating targets or high-purity copper superconducting materials, in terms of production technology, large-sized round ingots can be easily selected as blanks, and then processed into the required products by extrusion or forging; therefore, the quality of large-sized ingots is crucial, especially the uniformity of the internal structure and the grain size, which not only affect its processing performance, but also affect the quality of the processed products. It can be said that the more uniform and fine the internal structure of the ingot, the better its reprocessing performance and the better the quality of the processed products. However, the actual situation is that the larger the ingot size, the more difficult it is to control the uniformity of the internal structure, and the larger the grain size.

[0004] In general, the higher the purity and the larger the size of the ingot, the easier it is to have coarse grain structure, because the purer the metal, the lower the nucleation rate during crystallization, the larger the grain, and the larger the size, the slower the cooling, and the easier it is for the grain to grow, so large-size high-purity copper ingots tend to have coarse grains. The typical characteristics of pure copper ingots cast by traditional continuous casting are "coarse equiaxed crystals in the center, developed columnar crystals in the middle, and relatively fine equiaxed crystals at the edges" or "coarse equiaxed crystals in the center, developed columnar crystals from the middle to the edges", especially the larger the ingot diameter, the slower the cooling rate, and the more developed the columnar crystals. This kind of ingot with extremely uneven coarse structure is very unfavorable for reprocessing, the plasticity deteriorates, and even cracking during processing, and the processed product structure is prone to residual traces of coarse dendrites, and the processed product is prone to uneven performance in various parts, etc. In order to obtain a large-scale high-purity copper ingot with uniform and fine internal structure, from the perspective of metallurgy, two aspects need to be taken into consideration. One is to increase the supercooling degree of high-temperature liquid metal during crystallization to promote a large number of nuclei to refine the grains, and the other is to prevent the growth of grains after nucleation and crystallization. In order to achieve the purpose of grain refinement, the existing process uses electromagnetic vibration casting. The ingot obtained by this method improves the casting quality and has a finer grain structure, but its production cost is high, and the coil of the electromagnetic vibration system is easily damaged and difficult to replace, which brings inconvenience to production.

[0005] To this end, it is necessary to develop a new method for preparing large-scale high-purity copper ingots, to address the internal quality of large-scale ingots, and to aim at obtaining large-scale high-purity copper ingots with uniform, fine and defect-free internal structure. Summary of the invention

[0006] The present invention provides a method for preparing a large-sized high-purity copper ingot, the purpose of which is to solve the problem of coarse and uneven internal structure of a large-sized high-purity copper ingot, prepare an ingot with uniform and fine structure, and meet the needs of processing high-quality products, such as meeting the ingots required for processing and manufacturing large-sized high-purity copper rotating targets, high-purity copper superconducting materials, etc. The present invention provides a casting process using a short crystallizer and installing and using an annular water retainer, so as to achieve the goal of preparing a large-sized high-purity copper ingot with uniform, fine and defect-free internal structure.

[0007] In order to meet the above objectives, the technical solutions provided by the present invention are as follows.

[0008] A method for preparing a large-size high-purity copper ingot comprises the following steps: Step 1: Install the short crystallizer on a movable casting trolley, with the center line of the short crystallizer perpendicular to the ground plane; install the annular water retainer directly below the short crystallizer by welding, with the annular water retainer and the short crystallizer on the same center line; Step 2: The ingot-lifting system in the casting well rises, and the movable casting trolley is fine-tuned so that the ingot-lifting head of the ingot-lifting system is inserted into the short crystallizer; Step 3, preheat the graphite tube, insert one end of the preheated graphite tube into the furnace head of the smelting furnace and lock it, tilt the furnace head to insert the other end of the graphite tube into the center of the short crystallizer; the graphite tube inserted into one end of the furnace head is equipped with a flow limiting valve, and the flow limiting valve is in a closed state at this time; Step 4, tilt the furnace body, let the copper liquid flow into the furnace head, scald the furnace head for a certain period of time, then adjust the temperature of the copper liquid, let it stand for a certain period of time and keep it warm, adjust the furnace body so that the graphite tube inserted into the furnace head is aligned with the center of the short crystallizer and perpendicular to the horizontal plane of the short crystallizer; Step 5, open the flow limiting valve, the copper liquid enters the short crystallizer through the graphite tube, and the cooling water is immediately allowed to enter the cavity through the water inlet of the short crystallizer after the copper liquid enters the short crystallizer, and the cooling water pressure is 0.17 MPa-0.25 MPa; perform initial casting, the initial casting speed is half of the stable casting speed, and enter stable casting when the copper liquid level in the short crystallizer is 30 mm-40 mm away from the upper edge of the short crystallizer, at this time the graphite tube is immersed in the copper liquid in the short crystallizer, and the stable casting speed is 5.6 m / h-6.3 m / h; Step 6. The ingot guide head of the ingot guide system lifts the ingot and moves downward, and cooling water is sprayed out through the water outlet of the short crystallizer and splashes onto the surface of the lifted ingot. The cooling water on the surface of the ingot is refracted onto the annular water retainer, and then refracted onto the surface of the ingot again, and this is repeated many times; continuous and uninterrupted casting, when the copper liquid in the smelting furnace is poured out or the ingot length reaches the set value, the casting is completed, the ingot is taken out, and a large-sized high-purity copper ingot is obtained.

[0009] Further, in step 1, the short crystallizer 1 includes an inner sleeve 101; an outer sleeve 102 is provided on the outside of the inner sleeve 101, and a cavity is formed between the outer sleeve 102 and the inner sleeve 101; a water inlet 103 is provided on the side wall of the outer sleeve 102, and the water inlet 103 is connected to the cavity; a plurality of water outlet holes 104 are provided at the junction of the lower edge of the outer sleeve 102 and the inner sleeve 101, and the water outlet holes 104 are semicircular, and the water outlet holes 104 are connected to the cavity, and the water outlet holes 104 are evenly distributed in the circumferential direction of the lower edge of the outer sleeve 102.

[0010] Furthermore, the distance between the centers of each two adjacent water outlet holes 104 is 9 mm to 9.5 mm, the center line of the water outlet hole 104 forms an angle of 45° to 60° with the horizontal plane, the diameter of the water outlet hole 104 is 4 mm to 6 mm, and the height of the short crystallizer 1 is 130 mm to 180 mm.

[0011] Furthermore, in step 1, the annular water retainer 2 is prepared: after the rectangular metal plate is rolled into a cylinder, the seams are welded to obtain the annular water retainer 2; the rectangular metal plate is iron or ordinary carbon steel, the thickness of the rectangular metal plate is 2 mm to 4 mm, the height of the annular water retainer 2 is 130 mm to 200 mm, and the inner diameter of the annular water retainer 2 is 10 mm to 25 mm larger than the diameter of the lower edge of the inner sleeve.

[0012] Furthermore, in step 1, the distance between the annular water retainer 2 and the short crystallizer 1 is 10 mm to 20 mm.

[0013] Furthermore, in step 2, the starter head is stopped at a position 1 / 3 away from the lower edge of the short crystallizer 1, and the gap between the starter head and the short crystallizer 1 is blocked with asbestos cloth.

[0014] Further, in step 3, one end of the graphite tube inserted into the center of the short crystallizer is set at a position 50mm to 55mm away from the upper edge of the short crystallizer 1, and the graphite tube is perpendicular to the horizontal plane of the short crystallizer 1.

[0015] Furthermore, in step 4, the furnace head is scalded for 20 to 30 minutes, the temperature of the molten copper is adjusted to 1195° C. to 1215° C., and the standing time is 3 to 5 minutes.

[0016] Furthermore, in step 5, the copper liquid in the short crystallizer is covered with roasted red soot.

[0017] The present invention studies the characteristics of metal crystallization, namely the nucleation and growth mechanism, and studies how to achieve large-scale nucleation during liquid metal crystallization at high temperature and slow grain growth after nucleation, so as to achieve the purpose of grain refinement, make the ingot conducive to subsequent reprocessing, and produce higher quality products.

[0018] The principle of the method of the present invention is as follows: after the liquid metal crystallizes into a shell in a short crystallizer to form an ingot prototype, under a certain casting speed condition, by using a short crystallizer for continuous casting, the ingot can be lifted out of the short crystallizer faster and continuously, shortening the retention time of the high-temperature ingot in the short crystallizer, and at the same time, the ingot that leaves the short crystallizer is immediately cooled by the water sprayed from the short crystallizer, prompting the liquid metal in the uncrystallized area inside the ingot to form more nuclei when encountering strong cooling, and also causing the crystallized metal to cool down quickly, preventing the growth of grains; by installing and using an annular water retainer, the water sprayed on the surface of the ingot is refracted, splashing on the water retainer surrounding the ingot, and then refracted from the water retainer to the surface of the ingot again, and the water is repeatedly refracted and sprayed on the surface of the ingot, which strengthens the water cooling effect, the ingot cools down faster, and the grains are prevented from growing, thereby obtaining an ingot with uniform and fine structure. The preparation method of the ingot with uniform and fine structure provided by the present invention has good operability, high production efficiency, low production cost, and can form industrialized batch production.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows.

[0020] (1) Short crystallizer casting characteristics: The height of the short crystallizer is 130-180 mm. Under continuous casting conditions, the residence time of the high-temperature ingot in the short crystallizer is shortened. During casting, water enters the cavity through the water inlet to cool the copper liquid into a shell. The discharged water is directly sprayed onto the ingot lifted out of the short crystallizer to strongly cool the ingot.

[0021] (2) An annular water retainer is installed under the short crystallizer. The water sprayed from the short crystallizer is refracted after reaching the surface of the ingot. The refracted water is sprayed onto the inner ring surface of the annular water retainer, and then refracted again to the surface of the ingot. The ingot is cooled again. The cooling water is refracted repeatedly in this way, which is equivalent to spraying water to cool the ingot multiple times in a row, thereby enhancing the cooling effect, cooling the ingot faster, and preventing the internal grains from growing.

[0022] (3) This process technology solution can make full use of the existing furnace casting and continuous casting of general non-ferrous metal processing enterprises without increasing investment, and can cast high-quality ingots at low cost. The ingots have uniform and fine structure and are easy to operate, clean and environmentally friendly. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Schematic diagram of the cross-sectional structure of the short crystallizer adapted to the annular water retainer.

[0024] Figure 2 Schematic diagram of a short crystallizer cross section.

[0025] Figure 3 Schematic diagram of the bottom structure of the crystallizer.

[0026] Figure 4 Comparison diagram of the cross-sectional structure of the ∮330 mm ingot prepared by Example 2 and the prior art (a, Example 1, b, prior art).

[0027] Label: 1. short crystallizer; 101. inner sleeve; 102. outer sleeve; 103. water inlet; 104. water outlet; 2. annular water retainer; 3. metal rod. DETAILED DESCRIPTION

[0028] The following will be combined with the attached Figure 1-Figure 4 The technical scheme of the present invention is clearly and completely described in detail with specific embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] A method for preparing a large-size high-purity copper ingot comprises the following steps: Step 1, install the short crystallizer on a movable casting trolley, with the center line of the short crystallizer perpendicular to the ground plane; the annular water retainer is installed directly below the crystallizer by welding with a metal rod, the distance between the annular water retainer and the short crystallizer is 10 mm to 20 mm, and the annular water retainer and the crystallizer have the same center line; Step 2: The ingot-lifting system in the casting well rises, and the movable casting trolley is fine-tuned so that the ingot-lifting head of the ingot-lifting system is inserted into the short crystallizer. The ingot-lifting head stops at a position 1 / 3 of the distance from the lower edge of the short crystallizer, and the gap between the ingot-lifting head and the short crystallizer 1 is blocked with asbestos cloth; Step 3, preheat the graphite tube, insert one end of the preheated graphite tube into the furnace head of the smelting furnace and lock it, tilt the furnace head to insert the other end of the graphite tube into the center of the short crystallizer, and set the end of the graphite tube inserted into the center of the short crystallizer at a position of 50mm to 55mm from the upper edge of the short crystallizer. The graphite tube is perpendicular to the horizontal plane of the short crystallizer. The graphite tube inserted into one end of the furnace head is equipped with a flow limiting valve, and the flow limiting valve is in a closed state at this time; Step 4, tilt the furnace body, the copper liquid flows into the furnace head, scald the furnace head for 20 minutes to 30 minutes, then adjust the temperature of the copper liquid to 1195℃~1215℃, let it stand for 3 minutes to 5 minutes and keep it warm, adjust the furnace body so that the graphite tube inserted into the furnace head is aligned with the center of the short crystallizer and perpendicular to the horizontal plane of the short crystallizer; Step 5, open the flow limiting valve, the copper liquid enters the short crystallizer through the graphite tube, and the cooling water enters the cavity through the water inlet of the short crystallizer immediately after the copper liquid enters the short crystallizer, and the cooling water pressure is 0.17MPa-0.25MPa; perform initial casting, the initial casting speed is half of the stable casting speed, and enter stable casting when the copper liquid level in the crystallizer is 30mm-40mm away from the upper edge of the short crystallizer, at this time, the graphite tube is immersed in the copper liquid in the short crystallizer, the stable casting speed is 5.6 m / h-6.3m / h, and the copper liquid in the short crystallizer is covered with roasted red ash; Step 6. The ingot guide head of the ingot guide system lifts the ingot and moves downward, and cooling water is sprayed out through the water outlet of the short crystallizer and splashes onto the surface of the lifted ingot. The cooling water on the surface of the ingot is refracted onto the annular water retainer, and then refracted onto the surface of the ingot again, and this is repeated many times; continuous and uninterrupted casting, when the copper liquid in the smelting furnace is poured out or the ingot length reaches the set value, the casting is completed, the ingot is taken out, and a large-sized high-purity copper ingot is obtained.

[0030] Further, in step 1, the short crystallizer 1 includes an inner sleeve 101; an outer sleeve 102 is provided on the outside of the inner sleeve 101, and a cavity is formed between the outer sleeve 102 and the inner sleeve 101; a water inlet 103 is provided on the side wall of the outer sleeve 102, and the water inlet 103 is connected to the cavity; a plurality of water outlet holes 104 are provided at the junction of the lower edge of the outer sleeve 102 and the inner sleeve 101, and the water outlet holes 104 are semicircular, and the water outlet holes 104 are connected to the cavity, and the water outlet holes 104 are evenly distributed in the circumferential direction of the lower edge of the outer sleeve 102.

[0031] Furthermore, the distance between the centers of each two adjacent water outlet holes 104 is 9 mm to 9.5 mm, the center line of the water outlet hole 104 forms an angle of 45° to 60° with the horizontal plane, the diameter of the water outlet hole 104 is 4 mm to 6 mm, and the height of the short crystallizer 1 is 130 mm to 180 mm.

[0032] Furthermore, in step 1, the annular water retainer 2 is prepared: after the rectangular metal plate is rolled into a cylinder, the seams are welded to obtain the annular water retainer 2; the rectangular metal plate is iron or ordinary carbon steel, the thickness of the rectangular metal plate is 2 mm to 4 mm, the height of the annular water retainer 2 is 130 mm to 200 mm, and the inner diameter of the annular water retainer 2 is 10 mm to 25 mm larger than the diameter of the lower edge of the inner sleeve.

[0033] Example 1.

[0034] The invention is adopted to produce high-purity copper ∮300mm round ingots.

[0035] 1. A short crystallizer 1 comprises an inner sleeve 101; an outer sleeve 102 is provided on the outer surface of the inner sleeve 101, and a cavity is formed between the outer sleeve 102 and the inner sleeve 101; a water inlet 103 is provided on the side wall of the outer sleeve 102, and the water inlet 103 is connected with the cavity; 100 water outlet holes 104 are provided at the junction between the lower edge of the outer sleeve 102 and the inner sleeve 101, the water outlet holes 104 are semicircular and have a diameter of 5 mm, the water outlet holes 104 are connected with the cavity, the water outlet holes 104 are evenly distributed in the circumference of the lower edge of the outer sleeve 102, and the center line of the water outlet hole 104 forms an angle of 55° with the horizontal plane. The height of the short crystallizer 1 is 150 mm, the diameter of the lower edge of the inner sleeve 101 is ∮309 mm, and the diameter of the upper edge of the inner sleeve 101 is ∮311 mm.

[0036] 2. Preparation of the annular water retainer 2: After the rectangular metal plate is rolled into a cylinder, the seams are welded to obtain the annular water retainer 2; the rectangular metal plate is ordinary carbon steel, the thickness of the rectangular metal plate is 3mm, the height of the annular water retainer 2 is 160mm, and the inner diameter of the ring of the annular water retainer 2 is 325mm.

[0037] 3. A method for preparing a high-purity copper ∮300 mm round ingot comprises the following steps: Step 1, install the short crystallizer 1 on a movable casting trolley, with the center line of the short crystallizer 1 perpendicular to the ground plane; the annular water retainer 2 is welded and installed at a position 15 mm directly below the short crystallizer 1 by means of a metal rod 3, on the same center line as the short crystallizer 1; Step 2, the ingot-lifting system for lifting the ingot in the casting well rises, and the movable casting trolley is fine-tuned so that the ingot-lifting head of the ingot-lifting system is inserted into the short crystallizer 1, and the ingot-lifting head is inserted into the short crystallizer 1 at a position 1 / 3 of the distance from the lower edge. The ingot-lifting head, the short crystallizer 1, and the annular water retainer 2 are on the same center line, and the gap between the ingot-lifting head and the short crystallizer 1 is blocked with asbestos cloth; Step 3, preheating the graphite tube, inserting one end of the preheated graphite tube into the furnace head of the smelting furnace and locking it, tilting the furnace head to insert the other end of the graphite tube into the center of the short crystallizer 1, and setting the end of the graphite tube inserted into the center of the short crystallizer at a position 55mm away from the upper edge of the short crystallizer 1; the graphite tube inserted into one end of the furnace head is equipped with a flow limiting valve, and the flow of the copper liquid is controlled by the flow limiting valve during casting to control the casting speed; at this time, the flow limiting valve is in a closed state; Step 4, tilt the furnace body, let the copper liquid flow into the furnace head, scald the furnace head for 25 minutes to fully preheat the furnace head, then adjust the temperature of the copper liquid to 1200℃, let it stand for 4 minutes and keep it warm, and fine-tune the furnace body so that the graphite tube embedded in the furnace head is aligned with the center of the short crystallizer 1 and perpendicular to the horizontal plane of the short crystallizer 1; Step 5, open the flow limiting valve, the copper liquid enters the short crystallizer 1 through the graphite tube, and the cooling water enters the cavity through the water inlet 103 immediately after the copper liquid enters the short crystallizer 1, and the cooling water enters the cavity of the short crystallizer 1 to cool the copper liquid to make it crystallize into a shell, and the cooling water pressure is 0.19MPa; the initial casting speed is 3.0m / h, and when the copper liquid level in the short crystallizer 1 is 35mm away from the upper edge of the short crystallizer 1, normal stable casting is entered, and the graphite tube is immersed in the copper liquid in the short crystallizer 1 at this time, and the casting speed is 5.9m / h; the copper liquid in the short crystallizer 1 is covered with roasted red ash to protect the copper liquid from pollution and properly keep it warm; Step 6, the ingot head lifts the ingot and moves downward, cooling water is sprayed out through the water outlet 104 at the lower edge of the short crystallizer 1 and splashes onto the surface of the lifted ingot, so that the ingot is cooled quickly, and the annular water retainer 2 surrounds the ingot, covering the water reflected back from the surface of the ingot, and the water encounters the annular water retainer 2 and refracts to the surface of the ingot again, repeatedly taking away the heat of the ingot and strengthening the cooling of the ingot in the high-temperature state; continuous and uninterrupted casting, when the copper liquid in the smelting furnace is poured out or the ingot length reaches the set value, the casting is completed, and a high-purity copper ∮300mm round ingot is obtained; the smelting furnace body returns to its original position; the movable casting trolley is removed, the ingot is taken out, and the casting system returns to its original position.

[0038] Example 2.

[0039] The invention is used to produce high-purity copper ∮330mm round ingots 1. A short crystallizer 1 comprises an inner sleeve 101; an outer sleeve 102 is provided on the outer surface of the inner sleeve 101, and a cavity is formed between the outer sleeve 102 and the inner sleeve 101; a water inlet 103 is provided on the side wall of the outer sleeve 102, and the water inlet 103 is communicated with the cavity; 110 water outlet holes 104 are provided at the junction of the lower edge of the outer sleeve 102 and the inner sleeve 101, the water outlet holes 104 are semicircular and have a diameter of 5 mm, the water outlet holes 104 are communicated with the cavity, the water outlet holes 104 are evenly distributed in the circumference of the lower edge of the outer sleeve 102, and the center line of the water outlet hole 104 forms an angle of 55° with the horizontal plane. The height of the short crystallizer 1 is 155 mm, the diameter of the lower edge of the inner sleeve 101 is ∮340 mm, and the diameter of the upper edge of the inner sleeve 101 is ∮342 mm.

[0040] 2. Preparation of the annular water retainer 2: After the rectangular metal plate is rolled into a cylinder, the seams are welded to obtain the annular water retainer 2; the rectangular metal plate is ordinary carbon steel, the thickness of the rectangular metal plate is 3 mm, the height of the annular water retainer 2 is 160 mm, and the inner diameter of the ring of the annular water retainer 2 is 358 mm.

[0041] 3. A method for preparing a high-purity copper ∮330 mm round ingot comprises the following steps: Step 1, install the short crystallizer 1 on a movable casting trolley, with the center line of the short crystallizer 1 perpendicular to the ground plane; the annular water retainer 2 is welded and installed at a position 15 mm directly below the short crystallizer 1 by means of a metal rod 3, on the same center line as the short crystallizer 1; Step 2, the ingot-lifting system for lifting the ingot in the casting well rises, and the movable casting trolley is fine-tuned so that the ingot-lifting head of the ingot-lifting system is inserted into the short crystallizer 1, and the ingot-lifting head is inserted into the short crystallizer 1 at a position 1 / 3 of the distance from the lower edge. The ingot-lifting head, the short crystallizer 1, and the annular water retainer 2 are on the same center line, and the gap between the ingot-lifting head and the short crystallizer is blocked with asbestos cloth; Step 3, preheating the graphite tube, inserting one end of the preheated graphite tube into the furnace head of the smelting furnace and locking it, tilting the furnace head to insert the other end of the graphite tube into the center of the short crystallizer 1, and setting the end of the graphite tube inserted into the center of the short crystallizer at a position 55mm away from the upper edge of the short crystallizer 1; the graphite tube inserted into one end of the furnace head is equipped with a flow limiting valve, and the flow of the copper liquid is controlled by the flow limiting valve during casting to control the casting speed; at this time, the flow limiting valve is in a closed state; Step 4, tilt the furnace body, let the copper liquid flow into the furnace head, scald the furnace head for 25 minutes to fully preheat the furnace head, then adjust the temperature of the copper liquid to 1205℃, let it stand for 5 minutes and keep warm, and fine-tune the furnace body so that the graphite tube embedded in the furnace head is aligned with the center of the short crystallizer 1 and perpendicular to the horizontal plane of the short crystallizer; Step 5, open the flow limiting valve, the copper liquid enters the short crystallizer 1 through the graphite tube, and the cooling water enters the cavity through the water inlet 103 immediately after the copper liquid enters the short crystallizer 1, and the cooling water enters the cavity of the short crystallizer 1 to cool the copper liquid to make it crystallize into a shell, and the cooling water pressure is 0.20MPa; the initial casting speed is 2.9m / h, and when the copper liquid level in the short crystallizer 1 is 35mm from the upper edge of the short crystallizer 1, normal stable casting is entered, and the graphite tube is immersed in the copper liquid in the short crystallizer 1 at this time, and the casting speed is 5.8m / h; the copper liquid in the short crystallizer 1 is covered with roasted red ash to protect the copper liquid from pollution and properly keep it warm; Step 6, the ingot head lifts the ingot and moves downward, the cooling water is sprayed out through the water outlet 104 at the lower edge of the short crystallizer 1 and splashes onto the surface of the lifted ingot, so that the ingot is cooled quickly, the annular water retainer 2 surrounds the ingot, covers the water refracted back from the surface of the ingot, the water encounters the annular water retainer 2 and refracts to the surface of the ingot again, repeatedly, takes away the heat of the ingot, and strengthens the cooling of the ingot in the high-temperature state; continuous and uninterrupted casting, when the copper liquid in the smelting furnace is poured out or the ingot length reaches the set value, the casting is completed, and a high-purity copper ∮330mm round ingot is obtained; the smelting furnace body returns to its original position; the movable casting trolley is removed, the ingot is taken out, and the casting system returns to its original position.

[0042] Using the existing crystallizer with a height of 250mm and without an annular water retainer, the cross-sectional structure of the ∮330mm ingot cast is as follows: Figure 4 b; the cross-sectional structure of the ingot prepared in Example 2 of the present invention is as shown Figure 4 a; Figure 4 It can be seen from the comparison that the interior of the ingot prepared in Example 2 of the present invention is uniform and fine.

Claims

1. A method for preparing a large-scale high-purity copper ingot, characterized in that: The steps include: Step 1: Install the short crystallizer on a movable casting trolley, with the center line of the short crystallizer perpendicular to the ground plane; install the annular water retainer directly below the short crystallizer by welding, with the annular water retainer and the short crystallizer on the same center line; Step 2: The ingot-lifting system in the casting well rises, and the movable casting trolley is fine-tuned so that the ingot-lifting head of the ingot-lifting system is inserted into the short crystallizer; Step 3, preheat the graphite tube, insert one end of the preheated graphite tube into the furnace head of the smelting furnace and lock it, tilt the furnace head to insert the other end of the graphite tube into the center of the short crystallizer; the graphite tube inserted into one end of the furnace head is equipped with a flow limiting valve, and the flow limiting valve is in a closed state at this time; Step 4, tilt the furnace body, let the copper liquid flow into the furnace head, scald the furnace head for a certain period of time, then adjust the temperature of the copper liquid, let it stand for a certain period of time and keep it warm, adjust the furnace body so that the graphite tube inserted into the furnace head is aligned with the center of the short crystallizer and perpendicular to the horizontal plane of the short crystallizer; Step 5, open the flow limiting valve, the copper liquid enters the short crystallizer through the graphite tube, and the cooling water is immediately allowed to enter the cavity through the water inlet of the short crystallizer after the copper liquid enters the short crystallizer, and the cooling water pressure is 0.17MPa-0.25MPa; perform initial casting, the initial casting speed is half of the stable casting speed, and enter stable casting when the copper liquid level in the short crystallizer is 30mm-40mm away from the upper edge of the short crystallizer, at this time the graphite tube is immersed in the copper liquid in the short crystallizer, and the stable casting speed is 5.6 m / h-6.3m / h; Step 6: The ingot dummy head of the ingot dummy system lifts the ingot and moves downward, and cooling water is sprayed out through the water outlet of the short crystallizer and splashed onto the surface of the lifted ingot. The cooling water on the surface of the ingot is refracted onto the annular water retainer, and then refracted onto the surface of the ingot again, and this is repeated many times; Continuous and uninterrupted casting. When the copper liquid in the smelting furnace is poured out or the ingot length reaches the set value, the casting is completed and the ingot is taken out to obtain a large-sized high-purity copper ingot.

2. The method for preparing a large-size high-purity copper ingot according to claim 1, characterized in that: In step 1, the short crystallizer (1) comprises an inner sleeve (101); an outer sleeve (102) is provided on the outer surface of the inner sleeve (101), and a cavity is formed between the outer sleeve (102) and the inner sleeve (101); a water inlet (103) is provided on the side wall of the outer sleeve (102), and the water inlet (103) is connected to the cavity; a plurality of water outlet holes (104) are provided at the junction of the lower edge of the outer sleeve (102) and the inner sleeve (101), the water outlet holes (104) are semicircular, the water outlet holes (104) are connected to the cavity, and the water outlet holes (104) are evenly distributed in the circumferential direction of the lower edge of the outer sleeve (102).

3. The method for preparing a large-size high-purity copper ingot according to claim 2, characterized in that: The distance between the centers of each two adjacent water outlet holes (104) is 9 mm to 9.5 mm, the center line of the water outlet hole (104) forms an angle of 45° to 60° with the horizontal plane, the diameter of the water outlet hole (104) is 4 mm to 6 mm, and the height of the short crystallizer (1) is 130 mm to 180 mm.

4. The method for preparing a large-size high-purity copper ingot according to claim 1, characterized in that: In the step 1, the annular water retainer (2) is prepared by rolling a rectangular metal plate into a cylinder and then welding the seams to obtain the annular water retainer (2).

5. The method for preparing a large-size high-purity copper ingot according to claim 4, characterized in that: The rectangular metal plate is made of iron or ordinary carbon steel; the thickness of the rectangular metal plate is 2 mm to 4 mm; the height of the annular water retainer (2) is 130 mm to 200 mm; the inner diameter of the annular water retainer (2) is 10 mm to 25 mm larger than the diameter of the lower edge of the inner sleeve.

6. The method for preparing a large-size high-purity copper ingot according to claim 1, characterized in that: In the step 1, the distance between the annular water retainer (2) and the short crystallizer (1) is 10 mm to 20 mm.

7. The method for preparing a large-size high-purity copper ingot according to claim 1, characterized in that: In step 2, the starter head is stopped at a position 1 / 3 of the distance from the lower edge of the short crystallizer (1), and the gap between the starter head and the short crystallizer (1) is blocked with asbestos cloth.

8. The method for preparing a large-size high-purity copper ingot according to claim 1, characterized in that: In step 3, the end of the graphite tube inserted into the center of the short crystallizer is set at a position 50 mm to 55 mm away from the upper edge of the short crystallizer (1), and the graphite tube is perpendicular to the horizontal plane of the short crystallizer (1).

9. The method for preparing a large-size high-purity copper ingot according to claim 1, characterized in that: In step 4, the furnace head is heated for 20 to 30 minutes, the temperature of the molten copper is adjusted to 1195° C. to 1215° C., and the temperature is left to stand for 3 to 5 minutes.

10. The method for preparing a large-size high-purity copper ingot according to claim 1, characterized in that: In the step 5, the copper liquid in the short crystallizer is covered with roasted red ash.

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