RU2412260C2 - Procedure for reduction smelting and installation for its implementation - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: installation consists of smelting reservoir, and of at least one electrode unit of two coaxial electrodes - hollow external and internal. The hollow external electrode is self-baked and continuously expendable; it is made in form of two coaxial pipes. The cavity of this electrode is filled with components of charge and current-conducting self-baking electrode mass. Further, the installation consists of hoppers-metering devices and of gas system of gases supply and exhaust during smelting into and from a gap between the external and internal electrodes. According to the procedure of smelting into the gap between the external and internal electrodes of the electrode unit there are supplied components of charge, into the cavity of the external electrode there are supplied components of charge and current conducting self-baking electrode mass, while into the cavity of the internal electrode there is supplied current-conducting self-baking electrode mass. Relative position of the external and internal electrodes is corrected with mechanisms of transfer moving each electrode in case of necessity.

EFFECT: continuous smelting process, raised reliability of operation, reduced material consumption and reduced prime cost of finish product.

5 cl, 1 dwg

Description

The invention relates to the field of electrothermics and can be used for controlled, including continuous, heating and melting of materials in a wide range from metals to non-metallic materials, including oxides.

Known ore reduction furnace, used, in particular, for the production of ferroalloys, containing several (usually three) vertical self-sintering electrodes {Shevtsov MS, Borodachev AS The development of electrothermal technology / Ed. Acad. A.F. Belova - M .: Energoatomizdat, 1983, p. 109-111). A self-sintering electrode, as a rule, is a metal cylindrical welded casing filled with a carbon electrode mass, and serves to supply electric current from the contact jaws of the electrode holder through the coked part of the electrode to the working space of the furnace melting capacity. In this case, electric current flows between the electrodes and the remelted material loaded into the working space of the furnace.

Also known is a device for conducting melting, comprising a melting bath and at least two electrode assemblies, each of which consists of two coaxially arranged cylindrical electrodes separated by a cavity open from above and from below. The method of melting involves placing the electrode assemblies in the melting bath, applying voltage to them, supplying inert gas to the interelectrode cavity of each electrode assembly, filling the melting bath with liquid melt, heating the melt with electric current between the electrode assemblies (preliminary patent of the Republic of Kazakhstan No. 14141, M Cl. H05B 6/46, H05B 6/54). This device is mainly used for conducting “liquid start” melting in the processing of refractory metals, their alloys, metal mixtures, refractory refractory oxides and carbides. At the same time, this design seems to be more universal, since the electrode assembly, including coaxial electrodes, is self-sufficient for heating and melting the processed material, regardless of the operation of other electrode assemblies installed in the melting furnace, and does not require a baking electrode.

The aim of the present invention is to develop a method for conducting reducing smelting and a device for its implementation, which allows for a continuous melting process, to increase the efficiency and reliability of the device, to reduce the consumption of materials and the cost of the final product.

The desired result is achieved in that in the device for conducting reduction smelting containing a melting capacity, at least one electrode assembly consisting of two coaxially arranged electrodes - a hollow outer and inner, according to the invention, the hollow outer electrode is made self-sintering, continuously expandable, in the form of two coaxial pipes, the cavity of which is filled with charge components and a conductive self-sintering electrode mass, the device contains metering hoppers for supplying the current lead conductive self-baking electrode paste and the components of the charge into the cavity of the outer electrode, hoppers for feeding batch materials to the gap between the outer and inner electrodes and a gas supply system and the selection of gases during the melting process. The internal electrode is made self-sintering, continuously expanding in the form of a pipe with a cavity filled with a conductive self-sintering electrode mass through a metering hopper. The components of the charge and conductive self-sintering electrode mass are located in the cavity of the outer electrode in the form of tubes coaxial with the tubes of the outer electrode. The components of the charge and conductive self-sintering electrode mass are located in the cavity of the outer electrode in the form of a mixture.

According to the invention, an electrode assembly made in the form of continuously expandable melts is used in the method for conducting reduction smelting, comprising placing at least one electrode assembly in the melting tank, loading charge components, supplying and selecting gases, applying voltage to the electrodes and igniting an electric arc. , hollow outer and inner electrodes, during the melting process, charge components are fed into the gap between the outer and inner electrodes of the electrode assembly, into the cavity of the outer electro yes, the charge components and the conductive self-sintering electrode mass, and the conductive self-sintering electrode mass into the cavity of the internal electrode, correct the relative position of the outer and inner electrodes by moving mechanisms, moving each of the electrodes as necessary, while during the melting process by means of a gas supply and selection system gases circulate the working gases selected from the smelting tank, feeding them into the gap between the outer and inner electrodes.

The invention is illustrated by drawings. Figure 1 shows a device for conducting melting, figure 2 (a, b, c) is an external electrode in section with examples of the distribution of the components of the charge.

The device includes a melting tank 1, at least one electrode assembly (2-9), a gas system for supplying / withdrawing gas during the melting process (16, 21). The electrode assembly consists of an outer 2 and an inner 3 electrodes arranged coaxially. The outer electrode 2 is made in the form of two coaxial pipes 4 with a cavity 5 between them, filled with charge components 6 and a self-sintering electrode mass 7. The inner electrode 3 can be made (for example, Fig. 1) in the form of a pipe 8 with a cavity 9 filled with a self-sintering electrode mass. The inner electrode can also be made in the form of a conductive graphite rod. The device is equipped with a metering hopper 10 for feeding a self-sintering electrode mass and / or charge components into the cavity 5 of the outer electrode and into the cavity 9 of the inner electrode and a hopper metering 11 for feeding the charge components into the gap 12 between the outer and inner electrodes. The current to the external electrode is supplied using the current supply 13, the current to the internal electrode is supplied using the current supply 14. Between the electrodes 2 and 3, an insulator 15 is installed for centering the electrodes, preventing pollution and breakdown of the interelectrode space, and equalizing the gas flow supplied to the cavity between the electrodes along the gas supply path 16, and the supply of the charge components from the hopper 11. A seal 18 is installed between the outer electrode 2 and the body of the melting tank 17. The outer electrode 2 is equipped with anizmom movement 19. The internal electrode 3 is provided with a moving mechanism 20, allowing the internal electrode to move simultaneously with the outer electrode and relative to the outer electrode.

The implementation of the method and the operation of the device is as follows. At least one electrode assembly is lowered into the melting tank 1 to a depth required by the process. The smelting tank in a known manner is filled in the recovery zone with remelted materials (charge components). In addition, the components of the charge are fed using a dispenser 10 into the cavity 5 of the outer electrode and, if necessary, using the dispenser 11 into the gap 12 between the outer and inner electrodes of the electrode assembly. A self-sintering electrode mass 7 is fed into the cavity 5 of the outer electrode, for example, a mixture of granular solid carbon materials (thermoanthracite and coke) with bonding coal sand. In this case, the components of the charge are distributed in the cavity of the outer electrode either in an orderly manner - in the form of a pipe coaxial with the outer electrode (Fig. 2a, b), or randomly - in the form of a mixture with a conductive self-sintering mass (Fig. 2c).

In the gap 12 between the outer and inner electrodes, a gas taken from the melting vessel through the gas sampling path 21, or a gas or gas mixture from external sources, is supplied through the gas supply path 16. Excessive gas is removed from the smelter using a gas removal system. Set the relative position of the electrodes corresponding to the melting mode. After this, by known methods, for example, an oscillator, an electric arc is ignited between the outer and inner electrodes. The electric arc 22 burns from the ends of the electrodes to the melt, partially the current flows through the remelted material and the melt (23). Produce heating and / or melt of remelted materials. Ready melt 23 is drained from the melting tank. As the working part of the outer (and / or inner) electrode is consumed and the charge components are processed, the electrodes are expanded (for example, by welding the tubes forming the electrodes) and reloaded using the bins 10 and 11 without stopping the melting process.

Thus, the remelted material (charge components) through the cavity of the outer electrode and the gap between the outer and inner electrodes are fed directly to the burning area of the electric arc, where it is restored most efficiently. In this case, the thermal energy generated by the arc is spent primarily on heating and melting the recovered components of the charge, its losses are reduced, in particular on the oxidation of self-sintering electrodes by exhaust gases, on radiation, which significantly increases the efficiency of the device. In addition, in the cavity between the two coaxial pipes forming the outer electrode, at high temperatures, chemical interaction of the charge components supplied together with the conductive self-sintering mass occurs, which leads to partial restoration of the remelted material. This allows you to more efficiently use the reducing agent and reduce its consumption. The type and shape of the distribution of the charge components in the cavity of the outer electrode is selected experimentally for specific melting purposes.

If several electrode assemblies are used in the smelting process, each of them works independently according to a mutually agreed scheme. In the event of failure of one or more electrode assemblies, the payload is redistributed between the others, which ensures the continuity of the melting process and increases the reliability of the device.

Claims (5)

1. A device for conducting recovery melting, containing a melting capacity, at least one electrode assembly, consisting of two coaxially arranged electrodes - a hollow outer and inner and a gas gas supply and selection system during the melting process, characterized in that the hollow outer electrode is made self-sintering continuously expandable, in the form of two coaxial pipes, the cavity of which is filled with charge components and a conductive self-sintering electrode mass, the device also contains dosage hoppers ry for feeding conductive self-sintering electrode mass and charge components into the cavity of the outer electrode and hopper batchers for feeding the charge components into the gap between the outer and inner electrodes. 2. The device according to claim 1, characterized in that the internal electrode is self-sintering, continuously expanding in the form of a pipe with a cavity filled by means of a metering hopper with a conductive self-sintering electrode mass. 3. The device according to claims 1 and 2, characterized in that the components of the charge and conductive self-sintering electrode mass are located in the cavity of the outer electrode in the form of tubes coaxial with the tubes of the outer electrode. 4. The device according to claims 1 and 2, characterized in that the components of the charge and conductive self-sintering electrode mass are located in the cavity of the outer electrode in the form of a mixture. 5. A method of conducting reduction smelting, comprising placing at least one electrode assembly in the melting tank, loading charge components, supplying and selecting gases, applying voltage to the electrodes and igniting an electric arc, characterized in that the electrode assembly is made in the form of the gap, continuously increasing the hollow outer and inner electrodes, during the melting process, charge components are fed into the gap between the outer and inner electrodes of the electrode assembly, and the outer electrode cavity a) charge components and a conductive self-sintering electrode mass, and a conductive self-sintering electrode mass in the cavity of the inner electrode, adjust the relative position of the outer and inner electrodes by moving mechanisms, moving each of the electrodes as necessary, while during the melting process by means of a gas supply and selection system gases circulate the working gases taken from the melting tank, feeding them into the gap between the outer and inner electrodes.

Images