SU737756A1 - Electric-arc furnace bath - Google Patents

Description

(54) BATH ARCH ELECTRIC OVEN

one

The invention relates to metallurgy, specifically to furnaces for the production of slag melts, and can be used in ferrous metallurgy, for example, in the design of arc slag melting electric furnaces for smelting synthetic slags used for steel refining.

A known electric arc slag-smelting furnace for smelting synthetic slags, the bath of which is made as follows. The hearth of the furnace is made of three rows of horizontal coal blocks. Slope blocks are also made of horizontal coal blocks, and the furnace walls are made of alternating, their rows of water-cooled brass or bronze plate refrigerators (seven sections of eight rows) alternating with rows of magnesite bricks stacked between the refrigerators dry on the plate. The brass (bronze) refrigerators on the top are framed by cast-iron water-cooled refrigerators, which are an imis a support for the magnesite wall lining, which is above the level of the slag melt. The furnace bath is thermally insulated with a layer of asbestos, magnesite filling and an electrode mass of 1.

The disadvantage of such a bath is the low, long-life resistance of the Lift and Slopes, caused by the presence of heat-insulating layers on the bottom and in the area of coal slopes, which leads to the operation of coal lining elements under conditions of high thermal strength. The high temperature of the coal lining of the bath, granchash, with overheated melts of aggressive slag and metal, leads to the rapid deterioration of such a lining. In addition, a large number of water-cooled refrigerators (108 pcs.) Complicates the maintenance of the furnace during repairs and the supply of pipes and pipes. The total duration of one repair of such a furnace is 13-17 days. Repairs are time consuming and expensive, which ultimately increases the cost of the products.

The aim of the invention is to increase

yes lining durability and simplification of furnace maintenance.

The goal is achieved by the fact that the slopes are made with a height equal to 1.3-2.0 heights of the bottom blocks, and backfilling is made of a material with a thermal conductivity of 0.05-0.5 of the thermal conductivity of the blocks.

It is envisaged that the blocks of the bottom and the slopes are made composite in a horizontal plane, with the level of docking located 0.2-0.5 below the upper level of the blocks of the bottom.

It is also envisaged that the water-cooled elements of the walls are assembled from vertically arranged rectangular copper plates with channels for the passage of water.

FIG. 1 shows a bath, vertical section; in fig. 2 - bath in plan, cut at the bottom level.

The bath contains a casing 1 and lining 2, the bottom of which is made of vertically mounted on a thin layer of heat-conducting gasket 3 bottoms 4 coal blocks 5. The wall lining is made of graphitized blocks 6 with a total height of 1.3-2.0 bottom height. Graphite blocks can be made either solid or split along the horizontal plane 7 below the upper level of the bottom at a distance of 0.2-0.5 of its height. The space between the graphitized blocks b and the casing 1 is filled with carbon-containing compensation fill 8 with a thermal conductivity coefficient of 0.05-0.5 thermal conductivity of graphite blocks. On top of the graphite Hbie blocks, water-cooled elements (refrigerators) 9 made of rectangular copper plates with drilled channels for the passage of water equal to or higher than the level of the melt in the bath are installed along the entire perimeter of the bath. The space between the refrigerators and the casing is filled with carbon gasket 10. The upper part of the walls 11 above the refrigerators is made of refractory bricks without a heat insulating layer. The bath casing 1 consists of a wall 12, a set of vertical beams 13 welded to the wall, and at least one horizontal band 14 encircling the casing with openings 15 that mate with the casing. The part of the casing below the coolers is irrigated with water by means of the outside of the casing of the collector 16 with splashes. On the bottom 4 of the housing there is a drainage trough 17 for collecting water. In addition, on the bottom of the casing, boxes 18 are made of beams 19 for air cooling. In the upper part there is a sandbox 20 for hermetic installation of the roof on it. The bath also has a slag entrance 21, a metal entrance 22 and a working window 23 for charging. A layer of protective coal gasket 24 is applied to the coal and graphitized blocks, and the outside refrigerators are protected with a layer of refractories 25 outside.

Bath electric arc furnace works as follows.

After all installation and lining operations are completed, the furnace bath is charged and includes all systems, including the cooling system of refrigerators, the irrigation system of the furnace casing, the air cooling system of the furnace bottom, the power supply system, and the like. The mixture is melted and the melt level is brought to the upper level of the coolers. After that, periodic slag releases and charge charging are carried out. Low level shlaka

must not fall below the bottom level of the refrigerators.

The use of graphitized blocks for bath slopes significantly increases their service life until repairs. This is also facilitated by the implementation of backfilling with a thermal conductivity of 0.05-0.5 of the thermal conductivity of graphite blocks, due to an increase in heat dissipation from the slopes, which makes them inert to the aggressive effect of sclac and metal. ...

The depth of the slope block connector is 0.2-0.5 times the height of the central blocks of the bottom eliminates the corroding of the block joints by metal or slag, which increases the service life of the lining, and during the overhaul of the furnace, it replaces only the upper part of the graphitized blocks, thereby reducing overhaul of the furnace.

The implementation of water-cooled elements in the form of vertically arranged copper rectangular plates with channels for the passage of water reduces the number of such cooled elements by 5-6 times and thereby simplifies maintenance.

furnace, reduce downtime for repairs.

Only a reduction in the number of refrigerators saves copper on one furnace with a capacity of 16,500 kVA 23 tons, which corresponds to 35 thousand rubles. At present, the service life of slopes on 16500 kVA furnaces,

Those who produce synthetic slag at the Novolipetsk Metallurgical Plant do not exceed 3-4 months, after which a major overhaul of the furnace with a duration of 13-17 days is required. The proposed design of slopes and bottom allows an increase in the service life of the furnace bath for a period of at least one year, which gives only a reduction in the overhaul repairs for the year with an economic effect of about 400–500 thousand rubles. In addition, the capacity of the furnace is increased by reducing downtime for repairs by 10-15%.

The total estimated economic effect

per kiln is 800 thousand rubles. in year.

Claims (3)

1. A bath of an arc-shaped electric furnace containing a casing covering the bottom and slopes made of carbon-containing blocks and separated with a backfill, and the walls are lined with refractory bricks with water-cooled elements, so as to increase the durability of the bath lining and simplify maintenance of the furnace made with a height equal to 1.3-2.0 heights of the bottom blocks, and backfill is made of a material with a thermal conductivity coefficient of 0.05-0.5 thermal conductivity of the blocks. 2. The bath according to claim 1, characterized in that the blocks of the bottom and slopes are made of components in a horizontal plane, with the level of docking located 0.2-0.5 below the upper level of the blocks of the bottom. 3. Bath on PP. 1 and 2, characterized in that the water-cooled wall elements are assembled from vertically arranged rectangular copper plates with channels for the passage of water. Sources of information taken into account during the examination 1. Zinurov I. Yu. And others. Arc steel-smelting furnaces. M., “Metallurgists, 1974, ch. Xiii. ig.2