RU1784089C - Electric arc direct current furnace - Google Patents

Abstract

In a direct current arc furnace, the base contact, that is to say the furnace electrode (7, 8, 11), must be insulated by insulating material from the metallic jacket of the furnace vessel. To this end, the baseplate (11) which supports the base contact essentially forms the base of the furnace vessel. This baseplate (11) rests on an inwardly projecting part (17) of the metallic vessel jacket (2), with insulating, or at least poorly electrically conductive material (18) placed between them. <IMAGE>

Description

The invention relates to a DC electric arc furnace for metal smelting.

The purpose of the invention is to increase the life of the furnace.

Figure 1 is given an electric arc furnace, side view; in FIG. 2 - node I in FIG. 1.

In FIG. 1 shows a DC electric arc furnace with a metal receiver 1, which is equipped with a metal casing 2. In this example, the furnace has only one electrode 3 included as a cathode, however, there can be two, three or more such electrodes. The electrode is hollow, i.e., the furnace is suitable for a reduction process, however, the invention is also applicable to a melting furnace with a continuous electrode as a cathode, usually graphite. In the case of reduction through the central channel 4 of the electrode, for example for the production of cast iron, slag, coke and lime are supplied. And under the electrode 3, an electrode spot, i.e., a melt surface devoid of slag, is obtained in the usual way. As usual, the furnace has a drain sock 5 and a window 6. At the base of the furnace is a conductive bottom. It is made of bricks 7, in which the metal conductors are located 8. The conductors 8 penetrate into the underlying layer of the lining 9, which is made of electrically conductive carbon bricks and is adjacent to the furnace masonry 10. The lining bricks 9 are arranged in one or more layers and laid on a spherical plate 11 bases. The plate 11 has a significant expansion and forms the base of the furnace. It is made of steel or copper and attached to the positive pole of the DC source 12. The conductor underneath must have a large length in order to ensure that the furnace current spreads over a large part of the hearth, thereby preventing the inclined position of the arc 13. The plate 11 is equipped with a cooling device 14. in order to keep the temperature as low as possible and protect it from heat from the furnace 15 indicates a gas outlet. Bricks 7, equipped with conductors 8, serve as a current path between the load 16 and consisting of external

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lining 9 and plate 11 with a conductive hearth, which, of course, can be made otherwise. Thus, instead of carbon bricks, other conductive assemblies can be used. According to the invention, the casing 2 of the metal receiver is extended to the center of the furnace in the radial direction and forms a protruding inward flange 17 of the casing. The plate 11 is located above the flange 17. In the section between the plate 11 and the flange 17 there is a section 18mz of insulating material. Thus, all parts of the bottom of the furnace are supported on the flange 17 of the casing. The elements of the furnace bottom are in a quasi-melting state in the metal heat exchanger 1. At the same time, the insulating material provides electrical insulation between the casing 2 and the base plate 11 and, therefore, the conductive hearth. For radial alignment, the end 19 of the casing flange 17 extends inwardly, which, however, does not reach the base plate. The edge of the square 11 is equipped with a wedge-shaped cross-section of the ring 20, balancing the load on the insulating material. As an insulating material, you can use either prefabricated elements, for example bricks or clinker bricks made of refractory material, freely laid on top of each other or CE) made of refractory mortar, or filled or compacted mass. It is important that the insulating material, in addition to low electrical conductivity, be resistant to compressive loads. Moreover, it should not be an isolator in the proper sense of the word. It is sufficient if the electrical conductivity of the insulating material is at least a decimal order less than the conductivity of the hearth in the direction of the vertical axis of the furnace. The filled or rammed embodiment is shown in more detail in Fig. 2, which shows the assembly A of the electric arc furnace. On the cylindrical casing 2, an annular plate is fixed in the form of which a casing flange 17 is made. A part passing along the tubular axis is welded to the inner perimeter of this plate - the end 19 of the casing flange bent inward. Similarly to Fig. 1, the plate 11 is provided at its edge with a leveling ring 20, which is here made in the form of a welded structure and contains a radial ring 21 and an axial tubular part 22. The tubular part 22 extends below the radial ring 21 and is welded to the support ring 23. During manufacture before laying the furnace masonry, the stove 11 is installed with the parts 21.22 and 23, aligned with insulating spacers (not shown) relative to the casing 2 and the plate, in the form of which the casing flange 17 is made and temporarily

fix. Then, the space between the casing 2, the flange 17 and the tubular part, from which the end 19 of the casing flange bent upward and the area adjacent to it from above is made, is filled with mass, for example,

refractory concrete, so that the rings 21 and 23 of the tubular part 22 are completely embedded in this mass, forming section 18. Then, other components of the furnace are installed in a known manner.

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Claims (7)

1. A DC electric arc furnace containing a metal receiver with a metal casing, at least one electrode as a cathode, a conductive hearth as an anode, consisting of electrically conductive bricks placed on a base plate, b, so that , in order to increase the service life, it is equipped with a section of insulating or an electrically non-conductive material located under the base plate at its end, and a metal casing covers the section. 2. Oven pop. 1, distinguished by the fact that the metal casing covering section, made in one piece with the metal casing of the metal receiver. 3. Stove pop. 1, characterized in that the metal casing, covering section, made in the form of an annular plate, rigidly connected to the casing of the metal receiver. 4. A stove according to claim 1, characterized in that the base plate is approximately spherical in shape, and an alignment ring is placed between it and the section of insulating material. 5. A stove according to claim 1, characterized in that the section of insulating material is made of separate blocks, for example, of clinker bricks, which are laid freely or fastened together by a refractory mortar. 6. Oven pop. 1, excellent with that the insulating material is a filled or tamped mass of refractory material, such as concrete. 7. The furnace according to paragraphs. 1.5 and 6, with the proviso that the electrical conductivity of the insulating material is at least a decimal order lower than that of the conductive hearth in the direction of the vertical axis of the furnace. twenty 17 D 18 I Figure 1 17