RU2166843C2 - Nonconsumable electrode - Google Patents

Abstract

FIELD: ferrous and nonferrous metallurgy; electric furnaces using nonconsumable electrodes dipped in slag melt. SUBSTANCE: nonconsumable electrode has water-cooled jacket, metal nozzle made of carbide-forming material, and current supply for tip. Axial through duct common for jacket and nozzle accommodates pipe made of highconductivity material such as copper. Bottom end of pipe is tightly joined with metal nozzle; current supply is connected to top end of pipe. Metal nozzle may be made of nonmagnetic steel. EFFECT: improved electrical characteristics and, hence, stability of electrode. 2 cl, 2 dwg

Description

 The invention relates to the field of non-ferrous and ferrous metallurgy, in particular to electric furnaces with non-consumable electrodes immersed in slag melt, intended for smelting ore raw materials and depleting recycled slag in the production of heavy non-ferrous metals, and can also be used on ore-thermal furnaces in the production of ferroalloys.

 Electrode designs are known, including an electrode body, a protective layer is applied to a part of which is immersed in the melt. Current supply is carried out through a yoke with cheeks that compress the electrode body [A.S. USSR N 401024]. Electrode designs similar to the previous one are also known, but for electrode protection it is equipped with an axial channel for gas purging [A. from. USSR N 337019]. The disadvantage of these electrodes is their expendability.

 The closest in technical essence is a non-consumable electrode [Boborin S.V., Rusakov M.R., Mosionds K.I. "Study of the operation and protection mechanism of electrodes immersed in slag melt during ore and lean smelting." Reports of the meeting "Electrotherm-94". St. Petersburg, 1994, pp. 162-170], consisting (Fig. 1) of a water-cooled part 1 and a metal tip of a carbide-forming material 2. An axial channel 3 for supplying a reducing gas passes through the water-cooled part and a metal tip. The water-cooled part, made of an electrically conductive (magnetic) material, is equipped with devices for supplying 4 and removing 5 coolant. For the purpose of sealing between the tip and the water-cooled jacket, gaskets are placed 6. The device for supplying current to the metal tip is an electric holder 7 mounted on the water-cooled jacket.

 The disadvantage of this device is the low electrical characteristics (large reactance of 0.1-0.14 μΩ and loss of electricity during the passage of current through the electrode).

 The aim of the present invention is to improve the electrical characteristics of the electrode.

 This goal is achieved by the fact that in a non-consumable electrode containing a water-cooled jacket and a metal tip of a carbide-forming material through which the through axial channel passes, according to the invention, the current supply to the metal tip is carried out through a cylindrical pipe made of a material with high electrical conductivity, for example copper, pipe placed inside a water-cooled jacket of non-magnetic material, the lower end of the specified pipe is firmly attached to the metal tip and connects with the last axial channel for gas purging, and the upper end leaves the water-cooled jacket, which tightly covers the cylindrical pipe. The metal tip can be made of non-magnetic steel, for example, of heat-resistant non-magnetic steel grade 12X18H9T.

 Placing a cylindrical pipe made of a material with high electrical conductivity in the axial channel of a water-cooled jacket made of non-magnetic material allows it to be used both for supplying protective gas and for supplying current to a metal tip. When an electric current passes through a cylindrical pipe made of a material with high electrical conductivity, such as copper, and passes along the axis of the electrode, the current passes through a section (from the upper end of the pipe to which the current is supplied, to the lower end that is tightly fastened with a metal tip), which has the minimum reactance of all possible options for the design of the power supply and current paths. In addition, the location of the power supply pipe in the water-cooled zone reduces heat loads and improves the electrical characteristics of the power supply device. Whereas in the prototype, the design of the current lead assembly (through a water-cooled holder to a metal water-cooled case) degrades its electrical characteristics due to the significant reactance of a portion of the electrical circuit directly from the holder to the working end of the electrode. The implementation of a water-cooled jacket of non-magnetic material reduces the loss of electricity to induce eddy currents in the above metal parts of the non-consumable electrode. Therefore, compared with the prototype in the claimed design of a non-consumable electrode, the electrical characteristics of the latter are much higher (0.1-0.14 μOhm and 0.017 μOhm, respectively) [A. Yekhanovich Handbook of physics and technology. M., Enlightenment, 1976, p. 111, tab. 145], and the loss of electricity is correspondingly less. When performing a metal tip of non-magnetic steel, energy losses are further reduced.

 Figure 2 presents the design of the indestructible electrode.

Non-consumable electrode includes:
- water-cooled shirt 1, made of non-magnetic heat-resistant steel, with nodes for supplying and discharging coolant;
- a metal tip 2 of carbide-forming material with a nozzle 3;
- a cylindrical pipe 4 of a material with high electrical conductivity (copper), forming a through channel 5 passing through a water-cooled jacket and tip, for purging the melt with a reducing gas;
- a device for supplying current to a metal tip, which is an electric holder 6, attached to the upper end of the copper pipe, the upper end of the pipe is located above the water-cooled jacket;
- node supply of reducing gas to the cylindrical pipe 7, located above the current supply.

 The lower end of the cylindrical pipe 4 is tightly attached to the metal tip 2 and communicates with the last axial channel 3 for purging gas, and the upper end leaves the water-cooled jacket 1, which tightly covers the above cylindrical pipe. Between the water-cooled jacket and the tip are located copper sealing plates 6, which also serve to improve the electrical contact of the cylindrical pipe and the tip.

 The inventive non-consumable electrode operates as follows.

 After supplying electricity to the electrodes, the non-consumable electrode is lowered down and, not reaching the melt level of 0.3-0.5 m, nitrogen is passed through the axial channel in an amount necessary to prevent nozzle filling. Immerse the electrode in the melt at a given power to the required depth, but not more than the length of the tip. Turn on the supply of reducing gas, bringing its flow rate to a predetermined value. In this case, the nitrogen supply is stopped or maintained at the required technological requirements. Electric current is supplied to the non-consumable electrode through an electric holder mounted on a copper pipe. Coolant is continuously supplied through the inlet of the water-cooled jacket.

 The proposed design of the electrode allows you to improve its electrical characteristics by 6-8 times, due to improved electrical characteristics increases the resistance of the electrode.

List of references
1. USSR author's certificate N 401024, 1971, cl. H 05 B 7/06.

 2. USSR author's certificate N 337019, 1962, cl. C 21 C 5/56.

 Z. Boborin S.V., Rusakov M.R., Mosionds K.I. "Study of the work and mechanism of protection of metal electrodes immersed in slag melt during ore and depletion smelting." Reports of the meeting "Electrotherm-94", "Problems of optimizing the technological regime and methods for calculating arc ore-thermal furnaces." St. Petersburg, June 7-8, 1994, pp. 162-170.

 4. Enakhovich A.S. Handbook of physics and technology. M., Enlightenment, 1976, p. 111, tab. 145.

Claims (2)

 1. Non-consumable electrode, including a water-cooled jacket and a metal tip made of carbide-forming material through which the through axial channel passes, a device for supplying current to the tip, characterized in that a cylindrical pipe made of high-material material is placed in the axial channel of the water-cooled jacket from non-magnetic material electrical conductivity, for example copper, the lower end of the pipe is tightly fastened to a metal tip and communicates with it by an axial channel, and a device for supplying current is connected Eno with the upper end of the pipe.  2. The device according to claim 1, characterized in that the metal tip is made of non-magnetic steel, for example, steel grade 12X18H9T.

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