RU2793619C1 - Method for producing continuous copper blank by top draw method and technological complex for implementing this method - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: technological complex for producing a continuously cast copper billet by pulling a continuously cast copper billet upwards contains a single melting complex (2) containing a melting induction channel furnace (3), an intermediate channel induction furnace (9) connected to it by a channel (8) and a distributing channel induction furnace (13) connected to the billet pulling device (16). Copper scrap, pressed into cubes, is hung above the furnace (3) with copper melt covered with a layer of birch coal, so that the cubes are placed on the bottom plane of the coal, due to which moisture is removed from them. Then the coal is pushed aside and the cubes are immersed in the melt. On the surface not covered with coal, slag is formed, which removes impurities from the melt, then the slag is removed, and the surface of the coal is levelled. Through the channels (4, 8, 10, 15) the melt sequentially passes through the intermediate compartment (6), furnace (9), intermediate compartment (12) and furnace (13), where it is processed. The melt is drawn by the device (16) from the furnace (13) in the form of a continuously cast billet.

EFFECT: obtaining a copper billet with stable parameters and low resistivity while reducing energy costs for production.

7 cl, 3 dwg

Description

The invention relates to the field of metallurgy and can be used in the processing of copper scrap.

Prior Art

Currently, copper rod for electrical purposes is made from copper cathodes on continuous casting machines of various types. These are the settings

production of continuously deformed copper rod (CCR CONTINUUS PROPERZI, SCR SOUTHWIRE, SMS-MEER CONTIROD), in which continuous casting and rolling installations are combined, and continuously cast copper rod (UPCAST OUTOKUMPU, etc.), in which copper rod is drawn through molds from the melt by the top pull method with further winding on the receiving device.

The disadvantage of these methods is the use of only copper cathodes as a charge material.

Closest to the claimed invention is the RF patent for the invention No. 2688103, IPC B22D 11/00, "METHOD OF OBTAINING A CONTINUOUS COPPER BLANK FOR ELECTRICAL PURPOSES AND A TECHNOLOGICAL COMPLEX FOR ITS IMPLEMENTATION".

The technological complex contains a crucible melting plant, a foundry ladle with a mechanism for its transportation, a continuous vertical casting plant, and a receiving device. In a crucible melting plant, melting and fire refining of a charge based on copper scrap containing at least 99.2 wt.% copper is carried out to obtain a refined melt containing at least 99.91 wt.% copper. The melt is poured into a casting ladle, transported to a continuous vertical casting plant, poured into the melting furnace of the installation, kept under a layer of charcoal, and a continuously cast billet in the form of a rod is pulled out of the melt covered with a layer of graphite. The resulting workpiece is wound on a receiving device. EFFECT: possibility of using up to 100% copper scrap containing at least 99.2 wt.% copper to obtain a copper product for electrical purposes and reducing energy costs for production.

The disadvantage of this method is that the melting and fire refining of the copper charge in the induction crucible furnace requires a certain time, so the use of one induction crucible furnace for melting and refining the copper charge will cause temporary interruptions in the loading of the melting furnace of the continuous casting plant. This may cause intermittent changes in the amount of molten copper in the continuous casting plant, which may adversely affect the temperature stability of the copper melt in the holding furnace, and therefore adversely affect the stability of the characteristics of the finished product. To ensure the continuity of the refined melt supply to the melting furnace of the continuous casting installation, at least 2 induction crucible furnaces are required for melting and refining the copper charge, which increases the energy costs for the production of continuously cast copper rod and, accordingly, increases the cost of the finished product. The use of a large-volume ladle also causes temperature unevenness in the continuous casting melting furnace, which is caused by the natural cooling of the copper melt during a long process of supplying the melt from the ladle to the induction melting furnace. This also increases the energy consumption for ensuring the temperature regime in the melting furnace and, accordingly, increases the cost of the finished product.

Disclosure of invention

The objective of the claimed invention is to eliminate the disadvantages of analogues, namely, minimizing, up to elimination, the use of expensive raw materials in the form of copper cathodes, as well as reducing energy costs for the production of copper rod, which affects the cost of the final product.

The technical result of the claimed invention is to ensure the use of up to 100% copper scrap for the production of copper rod while maintaining the quality of the final product, namely, stable parameters and low resistivity of copper rod, as well as reducing energy costs for the production of wire rod.

The technical result is also achieved due to the fact that the technological complex for producing a continuously cast copper billet by pulling a continuously cast copper billet up, contains a receiving device and a melting complex, made in the form of a single installation and containing channel-type induction furnaces: melting and intermediate, connected through a connecting channel and distributing, as well as a top link device. All channel-type furnaces are additionally equipped with refractory baffles with overflow channels, which are designed to prevent overflow of the melt with an open jet. And the melting and intermediate furnaces additionally have intermediate sections for holding and melt recovery.

The method for producing a continuously cast copper billet in a technological complex comprises transporting a refined melt from a channel-type melting induction furnace through a connecting channel in a continuous way to an intermediate induction furnace, and then to a distributing induction furnace, and then to a device for drawing a continuously cast copper billet and to a receiving device. For the proposed method, up to 100% copper scrap is used, which is pre-pressed into cubes. The scrap cubes are heated on a layer of birch charcoal lying on the melt in a melting furnace until complete loss of moisture, and then the scrap cubes are immersed in the melt at a rate calculated depending on the pulling speed of the continuously cast copper billet, while controlling the level of change in the melt mirror. Then, the hard-to-remove slag obtained as a result of contact with oxygen, which has absorbed impurities, is removed. And then, through the overflow channel, the intermediate holding and recovery compartment and the connecting channel, the melt is fed into the intermediate furnace in a continuous flow. After processing the melt in the intermediate furnace, it is fed into the distributing induction furnace through the overflow channels and the next intermediate holding and recovery section. At the end of the casting process, a continuous billet is drawn out by means of a continuous casting copper billet pulling device and fed to a receiving device.

The continuous casting process makes it possible to obtain copper rod while maintaining the quality of the final product, namely, stable parameters and low resistivity of copper rod, as well as reducing energy costs for the production of wire rod.

Figure 1 Presents a diagram of the technological complex for producing continuously cast copper billets by pulling continuously cast copper billets up.

Figure 2 presents a top view of the installation of continuous casting, which is part of the technological complex for producing continuously cast copper billets by pulling continuously cast copper billets up.

Figure 3 shows a cross section of the installation of continuous casting, which is part of the technological complex for producing continuously cast copper billets by pulling continuously cast copper billets up.

Implementation of the invention

Technological complex 1 for producing a continuously cast copper billet by pulling a continuously cast copper billet upwards contains a melting complex 2 with a transport mechanism 7 and receiving devices 17, with the possibility of winding the obtained continuously cast copper rod. Melting complex 2 is made as a single unit and contains three channel-type induction furnaces: melting and intermediate, connected by a transport mechanism 7, and a holding furnace. The melting induction furnace of the channel type 3 is made with an overflow channel 4, a refractory partition 5 and an intermediate compartment for holding and reducing the melt 6, with the possibility of melting copper scrap. The transport mechanism 7 is made in the form of a connecting channel 8 with the possibility of transporting the refined melt in a continuous way. The intermediate induction furnace of the channel type 9 is made with an overflow channel 10, a refractory wall 11 and an intermediate section for holding and reducing the melt 12, with the possibility of holding the melt. The intermediate furnace is connected to a channel-type distributing induction furnace 13, made with a refractory wall 14 and an overflow channel 15, with the possibility of holding and transporting the melt to the device for pulling the continuously cast copper billet up 16. In this case, all the overflow channels in the refractory walls are made in such a way that the overflow open jet melt is excluded.

The claimed method is implemented as follows.

The charge, consisting only of copper scrap, is pressed into cubes using a hydraulic press.

The scrap cube is suspended above the channel-type induction melting furnace (3) by means of a lifting device in such a way that the lower surface of the cube stands on a layer of birch charcoal covering the surface of the liquid copper melt, while not touching the surface of the liquid copper melt. In this position, due to the temperature of birch charcoal, a cube of pressed copper scrap is heated to a temperature of 130-150ºС. Warming up is necessary to remove possible residual moisture in the scrap. At the same time, the thickness of the birch charcoal layer is 12-15 cm.

After the pressed scrap cube reaches a temperature of 130-150 ºС, the birch charcoal covering the surface of the liquid copper melt moves away from the center to the edges of the melting induction furnace (3), while opening the melt mirror. A cube of compressed scrap is immersed in the melt, while the immersion rate must be such that the temperature regime of the liquid copper melt is not disturbed, namely, the temperature of the copper melt must be from 1140 to 1150 ºС. In addition, the rate of immersion of scrap into the melt should be such that the level of the copper melt mirror changes by no more than 10-15 mm relative to the initial level. In this case, due to the contact of the open mirror of the melt with atmospheric air, the oxidative treatment of the melt occurs. In this case, the oxygen content rises to 0.2-0.5 wt.%, to obtain hard-to-remove slag, which allows you to remove impurities from the melt.

After the cube of pressed scrap is completely immersed in the melt, the slag is completely removed. After that, the surface of the coal is leveled. There is a recovery treatment of the liquid copper melt.

The dipping rate is calculated based on the drawing speed of the copper billet and can be determined from the relationship

M _immersion \u003d K * M _vyt ,

where M _immersion is the rate of immersion of the copper charge into the melting furnace, kg/min;

М _vyt is the speed of drawing the copper billet from the holding furnace, kg/min;

K - technological coefficient. The technological coefficient can range from 1.1 to 1.3, depending on the volume of furnaces and the number of copper billets simultaneously drawn. The excess of the amount of the loaded copper charge over the amount of the drawn copper billet is necessary in order to clean the melt mirror from slags, level and replace (if necessary) coal, and start the recovery processing of the liquid copper melt. In this case, the temperature regime of the melt and the level of the melt mirror should not go beyond the above ranges.

The liquid melt of copper from the melting induction furnace of the channel type (3) through the overflow channel (4) located in the refractory wall (5) enters the intermediate compartment for holding and reducing the melt of the melting induction furnace (6). At the same time, the surface of the copper melt in the intermediate holding and reduction compartment (6) is covered with a layer of birch coal 15–18 cm thick.

Periodically, in accordance with the requirements of the technological process, a deoxidizer is introduced into the melt, namely phosphoric copper, in the amount of 0.1 - 0.2% of the mass of the pressed scrap cube. In this case, the deoxidizer is introduced into the liquid copper melt located in the intermediate holding and recovery compartment (6). In this case, the recovery processing of the liquid copper melt occurs.

From the intermediate holding and reduction compartment (6), the copper melt is transported through the connecting channel (8) of the transport mechanism (7) to the intermediate channel-type induction furnace (9) of the melting complex (2). In the intermediate induction furnace (9), copper is reduced with periodic monitoring of the chemical composition of the copper melt. The frequency is determined by the requirements of the technological process, but at least 8 times a day.

According to a particular implementation of the technological process:

- in the liquid melt of copper, intermediate induction furnace (9), a deoxidizer, namely phosphoric copper, can be introduced in the amount necessary to meet the requirements of the technological process;

- in the intermediate induction furnace (9), the chemical composition of the melt can be adjusted by adding cathode copper to the melt.

At the same time, the liquid melt of copper located in the intermediate induction furnace (9) is under a layer of birch coal 15-18 cm thick.

The liquid copper melt from the intermediate induction furnace (9) through the overflow channel (10) located in the refractory wall (11) enters the intermediate section for holding and reducing the melt of the intermediate induction furnace (12). At the same time, the surface of the copper melt in the intermediate holding and reduction compartment (12) is covered with a layer of birch charcoal 15–18 cm thick. In the intermediate holding and reduction compartment (12), liquid copper is finally restored, calmed down and streamlines the structure of the melt.

Then, through the overflow channel (15), located in the refractory partition (14), the liquid copper melt flows from the intermediate holding and reduction compartment (12) to the channel-type distributing induction furnace (13), where it is under a layer of flake graphite 6-9 cm thick Moreover, the particle size of graphite is 0.495-0.500 mm, and the iron content does not exceed 0.05%.

The oxygen content in the distributing induction furnace (13) is reduced to the level of 0.001 wt.% and below, and the phosphorus content is 0.001-0.0015 wt.%. At the beginning of the casting process, a seed (copper rod) is fed into the molds of the upper draft device of the distributing induction furnace (16), immersed in the liquid copper melt in the distributing induction furnace (13). When the seed comes into contact with the melt, the crystallization process begins, and the seed moves up with the help of an exhaust device, pulling out a continuous workpiece in the form of a rod.

The resulting workpiece is wound on the receiving device (17).

Thus, the claimed invention makes it possible to obtain from copper scrap a continuously cast copper rod with electrical resistivity that meets the requirements of GOST R 53803-2010.

In addition, due to the elimination of additional induction crucible furnaces for melting scrap from the process, up to 500 kW/h is saved in the production of copper rod, which makes it possible to reduce the cost of the final product.

In addition, due to the continuous supply of "hot" metal in the installation of continuous casting by the top draft method, a constant temperature regime and mass volume of the liquid copper melt are maintained, which makes it possible to ensure the stability of the electrical characteristics of copper rod throughout the entire technological process, as well as to increase the life of the lining. installation at least 2 times.

All the above descriptions of the operation of the device confirm the fulfillment of the task of this invention, namely, the elimination of the disadvantages of analogues, namely, minimizing, up to elimination, the use of expensive raw materials in the form of copper cathodes, as well as reducing energy costs for the production of copper rod, which affects the cost final product.

Industrial Applicability

All of the above speaks of the industrial applicability of the technological complex for producing continuously cast copper billet by pulling the continuously cast copper billet up and the method for producing continuously cast copper billet in this technological complex.

List of positions.

1. Technological complex

2. Melting complex

3. Melting channel type induction furnace

4. Flow channel of melting induction furnace

5. Refractory baffle of melting induction furnace

6. Intermediate compartment for holding and reducing the melt of the melting induction furnace

7. Transport mechanism

8. Connecting channel

9. Intermediate channel-type induction furnace

10. Channel overflow intermediate induction furnace

11. Refractory baffle of intermediate induction furnace

12. Intermediate compartment for holding and reducing the melt of an intermediate induction furnace

13. Channel Type Dispensing Induction Furnace

14. Refractory baffle of holding induction furnace

15. Flow channel of distributing induction furnace

16. The device for drawing continuously cast copper billet of distributing induction furnace

17. Receiving device

Claims (7)

1. Technological complex for producing a continuously cast copper billet by pulling a continuously cast copper billet up, containing a melting complex (2) with a melting furnace (3), a transport mechanism (7), a distributing furnace (13) and a device (16) for pulling a continuously cast copper billet up with receiving devices (17) made with the possibility of winding the obtained continuously cast copper billet, characterized in that the melting complex (2) is made in the form of a single unit containing a melting induction furnace (3) of a channel type connected to it by a transport mechanism (7), made in the form of a connecting channel (8), an intermediate induction furnace (9) of the channel type and a distributing induction furnace (13) of the channel type, made with the possibility of holding and transporting the copper melt to the device (16) for pulling the continuously cast copper billet upwards, while the melting induction the furnace (3) of the channel type, made with the possibility of melting copper scrap, contains an intermediate compartment (6) for holding and reducing the copper melt and a refractory partition (5) with an overflow channel (4), the connecting channel (8) is made with the possibility of continuous transportation of the refined melt copper into an intermediate induction furnace (9) of a channel type, made with the possibility of holding a copper melt, containing a refractory partition (11) with an overflow channel (10) and an intermediate compartment (12) for holding and recovering the copper melt and connected to a distributing induction furnace (13) channel type, made with the possibility of holding and transporting the copper melt to the device (16) for pulling the continuously cast copper billet upwards, containing a refractory partition (14) with an overflow channel (15). 2. Technological complex according to claim 1, characterized in that the overflow channels in the refractory partitions are made to prevent the overflow of copper melt by an open jet. 3. A method for producing a continuously cast copper billet in the technological complex according to claim 1, including melting and refining a charge based on copper scrap, transporting a refined copper melt and vertical drawing of a continuously cast copper billet, followed by winding the billet on a receiving device (17), while the charge on based on copper scrap is pressed into cubes, which are hung over a melting induction furnace (3) of a channel type with a copper melt covered with a layer of birch charcoal, and the mentioned cubes are placed with their lower plane on a layer of birch charcoal without contact with the copper melt, until a temperature of 130-150 ° C is reached. C, whereby the remaining moisture in the cubes is removed, then the layer of birch charcoal is pushed aside and the scrap cubes are immersed in the copper melt at a speed calculated depending on the pulling speed of the continuously cast copper billet, while on the surface of the copper melt not covered with birch charcoal, due to the contact of the copper melt with oxygen, a hard-to-remove slag is obtained, by means of which impurities are removed from the copper melt, then the said slag is removed, and the surface of the birch charcoal layer is leveled and the copper melt is fed through the overflow channel (4) into the intermediate compartment (6) for holding and reducing the copper melt, where periodically a deoxidizer is supplied in an amount of 0.1-0.2% of the weight of the cube and the liquid melt of copper is reduced, which is fed through the connecting channel (8) into the intermediate induction furnace (9) of the channel type, in which the surface of the melt is covered with a layer of birch coal, and through the overflow channel (10) - into the intermediate holding and reduction compartment (12), where the copper melt is processed, and through the overflow channel (15) it is fed into the distributing induction furnace (13) of the channel type, where the copper melt is constantly covered with a layer of flake graphite, at At the same time, the oxygen content in the copper melt in the induction holding furnace is reduced to 0.001 wt.% and lower while controlling the phosphorus content in the copper melt at the level of 0.001-0.0015 wt.%, the molds of the device (16) for pulling the continuously cast copper billet up are immersed in the melt , the seed is fed in the form of a copper rod and the crystallization process is carried out when the copper melt comes into contact with the seed and the continuously cast billet is pulled upwards in the form of a rod, and the resulting billet is wound on the receiving device (17). 4. The method according to claim 3, characterized in that the speed of immersion of copper scrap cubes into the copper melt is controlled to ensure that the level of the copper melt mirror does not change by more than 10-15 mm relative to the initial level. 5. The method according to p. 3, characterized in that the temperature of the copper melt in the melting induction furnace while immersing cubes of copper scrap is maintained from 1140 to 1150°C. 6. The method according to p. 3, characterized in that phosphoric copper is used as the deoxidizer supplied to the intermediate holding and recovery compartment (6). 7. The method according to claim 3, characterized in that the thickness of the layer of flake graphite on the surface of the mirror of the copper melt in the distributing induction furnace (13) of the channel type is maintained equal to 6-9 cm, while the graphite particle size is 0.495-0.500 mm, and the content iron is not higher than 0.05 wt.%.

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