RU1770712C - Chute for discharging metal and separation of furnace slag - Google Patents

Abstract

Usage: in the steel industry. SUMMARY OF THE INVENTION: the trough comprises a lined casing with a recess in the side wall and a lined insert, with a pocket with a pass, a stationary skimmer partition located under the pocket, the base of the hole is located on the same level as the pass with the pocket. 3 ill.

Description

The invention relates to ferrous metallurgy, and in particular to steel production, and can be used in devices used to release steel from an assembly into a casting ladle.

In the known device, the furnace slag is separated from the metal by means of a movable gate, in front of which a partition is installed with a gap between the bottom, and the slag is discharged into the bowl through a recess in the side wall 1.

However, in this device, it is difficult to adjust the level of the metal in the gutter using a gate to allow slag to drain through the opening, since the metal in the gutter is covered with slag and it is quite difficult to determine the height of the metal bath in the gutter. Therefore, with excessive immersion of the gate in the gutter, steel overflow through the recess is possible. With a small immersion of the gate and a low level of metal in the gutter, the slag will be carried away by the stream of flowing metal and pass below the partition and the gate. In addition, in both the first and second cases, metal can pass between the gate and the walls of the trough due to the formation of accretions and mechanical destruction of the refractory lining. Thus, the specified device does not provide complete separation of the slag from the metal. In addition, the presence of a movable gate complicates the design of the gutter and its maintenance.

A device for the release, processing of metal and separation of furnace slag, taken as a prototype, comprising a lined casing with a recess in the side wall and a skimmer partition located behind it with a gap between the bottom, with a slope of the walls in the longitudinal direction 10-45 ° and the ratio of the length at micron to its width in the upper part is 5-15. The skimmer partition, consisting of stationary and removable parts, is deepened in the mouth with a height ratio from the bottom of the partition to the recess in the side wall and from the bottom of the partition to the pass at the mark within 1-2, while a fireproof inset is provided in the side wall of the gutter5

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which is located below the pass of the embankment with a height ratio from the bottom of the partition to the pass and from the bottom of the partition to the base of the insert within 1.1-2.

A disadvantage of the known device is the low efficiency of slag cutoff during operation of the steelmaking unit between repairs of the steel outlet. This is due to the fact that, as a steelmaking unit, for example, an open-hearth furnace, is used, as a result of erosion of the refractory masonry of the steel outlet, the rate of metal discharge from the furnace increases and the lower channel under the partition of the trough is not able to let all the metal through, which leads to overflow of the receiving compartment and overfilling metal through an open opening in the side wall of the gutter. In order to avoid an emergency situation caused by metal transfusion, it is necessary to remove the removable part of the upper channel partition. It is not possible to establish a removable partition in the same place after lowering the metal level in the receiving part of the gutter at the end of the discharge due to the formation of accretions on the walls of the gutter.

An increase in the throughput of the gutter by increasing the gap between the skimmer partition and the bottom by more than 2-4 times in comparison with the area of the steel outlet (2) leads to an increase in the dimensions of the gutter, the dimensions of which are limited by the conditions of its maintenance (connecting it to furnace) and the preparation of the hole for the release of melting, and the presence of free space in the area of the steel outlet.

Due to the insufficient throughput of the gutter, slag can be cut off only on the first smelting after repair of the steel outlet, which is 25-50% of the total overhaul amount of the smelting. On the remaining heats, overflow of the receiving part of the gutter is observed, as a result of which it is necessary to remove the removable extension of the baffle and work without cutting off the slag.

The low efficiency of slag cutoff during operation of the furnace leads to an excessive consumption of ferroalloys, deterioration in the quality of steel, and a decrease in the resistance of steel casting ladles.

The aim of the invention is to increase the efficiency of slag cut-off during operation of the furnace.

The goal is achieved. that the base of the excavation is located on the same level as the pass at the ICA.

On Fig, 1 shows a groove, longitudinal

incision; figure 2 is a section along aa in fig. 1; in Fig.3 is a section along BB in Fig.1.

The device contains a lined casing 1 with a recess 2 and a lined insert 3 in the side wall of the gutter, with a ball 4,

ending pass 5 connected to a drain toe 6 located above the intake skimmer partition 7, which divides the gutter into the receiving 8 and drain 9 compartments of the gutter and forms the lower 10

and the top 11 channels.

It differs from the prototype in that the base of the opening 2 with the lined insert 3 is located at the same level as the pass with the mark.

The implementation of the base of the outlet with the lined insert on the same level with the pass mark allows you to effectively cut off the slag during operation of the furnace at all heats, regardless of the degree

wear of the refractory masonry of the steel outlet. Due to a more efficient and stable slag cut-off, the number of custom heats increases, the quality of the metal improves, and the

the costs of deoxidizers and refractories, as the durability of the buckets increases.

A comparative analysis of the known technical solution and the claimed did not reveal similar features in them,

Therefore, the inventive device has significant differences.

The gutter works as follows. Before releasing the heat, a chute is connected to the steel outlet of the hearth steelmaking unit. A removable lined insert 3 is installed on the base of the recess 2 (with grease refractory masses and drying the seams) and attached with a cable to the casting hook

crane or specially installed winch. After cutting the steel outlet, the metal coming from the furnace fills at the gutter 4 troughs, passes through the lower channel 10 and, having reached the level

Pass 5, merges into a bucket. As the steel outlet erodes, the rate of metal discharge from the furnace increases and the lower channel is not able to let the metal through. Metal level in

5, the receiving compartment 8 of the trough rises and excess metal flows through the upper channel 11 into the drain compartment 9 of the trough. As the metal is discharged from the furnace, the ferrostatic pressure of the melt decreases and, as

as a result, the filling rate is reduced

the metal of the receiving compartment of the gutter. The metal level is set below the upper channel and the metal enters the drain compartment only through the lower channel. With the appearance of the first portions of slag in the receiving compartment of the gutter, it floats to the surface of the metal and is prevented from moving into the bucket by the skimmer baffle 7 and a hydraulic shutter formed by the metal in the gutter hole. As slag builds up, the metal level in the receiving compartment will decrease due to the static pressure of the slag layer. Thus, for example, a slag layer of height Hi will squeeze out a metal layer of height equal to half Hi from the receiving part, since the specific gravities of steelmaking slag and metal are approximately 1: 2. In this case, the metal level to the septum (Urs) will be located near the bottom of the septum, and beyond the septum at the level (Ur). Thus, the depth of the partition 7 relative to the pass 5 at MCA4, i.e. The depth of the hydraulic shutter Ng must be equal to at least half the height of the slag layer (, 5 Hi).

When the slag reaches the upper level of the partition 7, the lined insert 3 is removed using a crane or a winch and the slag through the formed hole 2 in the side wall along the slag chute is drained into the slag bowl and, with a decrease in the thickness of the slag layer in the chute, the metal moves from the drain compartment to the receiving compartment of the gutter until their levels are equalized. With the rise of metal in the mark before the partition, the slag located on its surface also rises, which, reaching the base of the outlet in the side wall, is drained through it into the slag bowl. After the metal and slag are discharged from the furnace, slag remains in the gutter, the amount of which is determined by the length, width of the receiving compartment of the gutter, and twice the distance from the pass to the metal level in the drain compartment.

The metal and slag remaining in the gutter receiver is drained into the bucket by lifting the gutter using a filling valve.

The lower and upper channels are involved in the work of the chute at the same time in the case of intense metal gathering, which is usually observed after 9-10 melts, starting with the repair of the steel outlet. The upper channel does not work with moderate metal gathering from the furnace.

In the proposed device, the location of the base of the opening 2 in the side wall is flush with the pass at mark 5 and the overlapping of the opening with a removable lined insert 10, as well as the use of the upper channel during the period of intensive descent

metal from the furnace allows slag to be effectively cut off during intensive convergence of the metal and slag from the furnace, i.e., on all smelting conducted between the repair of the steel outlet. If the base of the opening is located above the pass, then after the metal and slag are discharged from the furnace, a large amount of slag remains in the receiving compartment of the gutter, equal to twice the difference between the level of the base of the outlet and the level of the pass, which enters the steel pouring ladle after tilting the gutter. In addition, the height of the trough increases, which makes it difficult to cut the steel outlet, and also leads to an increase in the cost of refractories.

If the base of the outlet is below the pass of the mark, after removal of the removable lined insert 3, part of the metapool will be poured into the slag bowl, which leads to brewing of the slag bowls and lower yield of steel.

Example .. Slag was cut off at a 250-ton open-hearth furnace of the Makeevka Metallurgical Plant using a trench having a skimmer baffle, upper and lower channels for the passage of metal. The passage area of the lower channel was 0.12 m2, and the upper channel was 0.072 m2. The distance from the bottom of the partition to the upper channel corresponded to 1.05 m, the height from the bottom of the partition to the pass was 0.5 m. The height of the gutter was 1.2 m. A recess was made in the side wall of the gutter, which is equipped with a removable lined insert, with the base the excavation was at the same level as the pass at the ICA.

A groove was also tested on which the base of the opening with the lined insert was positioned 50 mm above and below the pass.

In the table. 1 shows the results of industrial tests of the gutter with a different arrangement of the opening with a lined insert in relation to the pass at the MCA.

When the base of the outlet is located below the pass, metal enters the slag bowl and welds it. With the opening located above the pass, the degree of slag cut-off decreased, since when tilting the gutter, much more slag got into the steel pouring ladle than it is necessary for thermal insulation of the metal mirror.

If the opening in the side wall was at the same level as the pass at the mark, no metal loss was observed and

brewing slag bowls with a sufficiently high degree of cutoff of slag.

Table 2 presents the data on the degree of slag cutoff and the number of heats conducted with the slag cutoff during operation of the furnace after repair of the steel outlet, using the gutter of the proposed design and adopted for the prototype.

The number of heats between repairs of the steel outlet in both cases was the same and amounted to 24 heats

Compared with the design of the gutter adopted for the prototype, the use of the gutter of the proposed design provides slag cut-off on all heats during operation of the furnace between repairs of the steel outlet, while the prototype gutter design allows the slag to be cut off on the first 10 heats

after repair of the steel outlet, which is 92% of the total number of heats.

As a result of the increase in the number of heats carried out with slag cut-off, reject 1 of the redistribution decreased by 0.04%, the consumption of ferromanganese by 20%, and the durability of steel casting ladles increased by 23%.

Claims (1)

The claims A chute for discharging metal and separating furnace slag, comprising a lined casing with a recess in the side wall and a lined insert, with a pass with a pass, a stationary skimmer baffle located above the acceptor, characterized in that, in order to increase the efficiency of slag cut-off, the base of the outlet is located at the same level as the accept pass. T a & l and ts a 1 table 2 n-th .L /// G //// L   sj Fie. 7 Figure 2 10 9  / 7 AU $ / l //, Fig.Z