RU2389958C1 - Notch brick - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: iron notch of furnace consists of notch brick, notch wall with recess and of furnace armour. The notch brick has dimensions 164x400x300 mm and made out of a mullite packed block. It is placed into a welded box and fixed in it with a fixing frame welded to the welded box and attached to four stops in angles of the welded box for additional fixation and retention the notch brick from pressure of melted metal. A frame with two hooks is welded to the front part of the welded box for removal of worn out notch brick together with the welded box. Also three brackets are welded to the frame of the welded box. The brackets are arranged at angle of 120° wherein there are made slots for locking wedges. For fixation of the welding box in the recess of the notch wall there are welded three brackets at angle of 120° with slots for the locking wedges coinciding with slots of the brackets welded to the frame of the welded box. End surface of the notch brick is lubricated with glue mastic of 2-4 mm layer; while outside surface of the welded box is wrapped with refractory wool before installation into the recess of the notch wall.

EFFECT: increased service life of notch brick.

2 cl, 2 tbl, 6 dwg

Description

Flying brick refers to ferrous metallurgy, can be used in shaft furnaces designed for smelting cast iron.

The analogue is known - flying brick for slag taphole (information source V. Ivanov, “Dictionary-reference book on foundry production.” - M.: “Mechanical Engineering”, 1990. - 384 p.).

Figure 1 schematically shows a flying brick for slag tap holes.

The summer brick for slag summer is a spherical brick with dimensions of 228 × 228 mm with a summer hole located slightly above the center. Flying brick for slag tap hole is made of high alumina refractory material (aluminosilicate refractories), which contains more than 45% Al ₂ O ₃ alumina. The raw materials for high-alumina refractory bricks for slag tap-hole are technical alumina and electrocorundum with the addition of refractory clay, as well as high-alumina rocks (kyanite, andalusite, diaspore, bauxite).

The disadvantages are that

- it is made only at refractory plants in Russia by special order;

- special equipment is necessary for manufacturing;

- as a rule, the flying brick for slag tap hole has a small thickness and during operation has a short service life;

- it is installed stationary in the lower part of the furnace and upon failure it is necessary to disassemble almost the entire lining of the furnace.

Due to the above disadvantages, it is impossible to obtain a technical result.

Of the known closest in technical essence (prototype) is fly brick for cast iron notch (information source V. Ivanov, “Dictionary-reference book on foundry production.” - M.: “Mechanical Engineering”, 1990. - 384 p.).

Figure 2 schematically shows a flying brick for a cast iron notch.

The summer brick for the cast iron notch is a straight brick (like fireclay brick SHA1 No. 5), having dimensions 228 × 115 × 65 mm with two holes:

- lower through;

- top deaf spare.

Flying bricks for cast-iron notches are made of high alumina refractory material (aluminosilicate refractories), which contain more than 45% Al ₂ O ₃ alumina. Basically, brick for cast-iron notches is made of mullite-siliceous refractory composition containing 45-62% Al ₂ O ₃ (usually MKRS-45). The physicochemical parameters of the summer brick for the cast iron notch are given in Table 1.

Table 1 Physico-chemical parameters of the flying brick for the cast iron notch of the MKRS-45 brand Mark MKRS-45 Al ₂ O ₃ , over 45 Fe ₂ O ₃ , no more 1.8 Open porosity,%, no more 24 Strength at compression, N / mm ² , not less twenty Refractoriness, ° С, not lower 1750 Softening start temperature, ° С, not lower 1400 Heat resistance, heat exchange, not less 3

Installation of summer bricks for cast iron tap holes is shown in figure 3.

The disadvantages are that

- are made only at refractory plants in Russia by special order;

- special equipment is necessary for manufacturing;

- due to the small thickness, the flying brick for the cast iron notch has a short service life;

- a flying brick for a cast iron notch is installed in the lower part of the melting furnace “stationary”, i.e. A worn out summer brick cannot be removed quickly and a new one should be installed in its place. Due to the above disadvantages, it is impossible to obtain a technical result.

The objective of the invention is to increase the service life (durability) of summer brick, as well as the possibility of quick replacement in case of wear.

EFFECT: developed design of summer brick differs in a long service life (durability) and the possibility of quick replacement in case of wear.

The specified technical result is achieved due to the fact that in the cast-iron notch of the furnace, in particular the mine, containing the flying brick, the flying wall with a niche, the armor of the furnace, according to the invention, a flying brick made with dimensions of 164 × 400 × 300 mm from the mullite compacted block is introduced placed in a welded box and fixed in it by a fixing frame welded to the welded box and attached to four stops located in the corners of the welded box for additional fixation and holding the summer brick from pressure molten metal. The proposed flying brick has a thickness of 2.52 times greater than the thickness of the prototype. Material for the manufacture of summer bricks has in its composition more Al ₂ O ₃ , less Fe ₂ O ₃ and lower porosity, and also has a much higher tensile strength and softening start temperature. The introduction of these elements provides an increase in the service life (durability) of summer brick.

At the same time, a frame with two hooks is welded to the front of the welded box to remove the worn-out summer brick together with the welded box. This design makes it possible to quickly replace summer brick in case of wear. In addition, three brackets located at an angle of 120 ° are welded to the frame of the welded box, in which grooves are made for the clamping wedges, and for mounting the welded box in the recess of the flight wall to the armor of the furnace, three brackets are welded at an angle of 120 ° with grooves for clamping wedges, coinciding with the grooves of the brackets welded to the frame of the weld box. The introduction of these elements provides reliable fastening of the weld box in the recess of the flight wall and easy quick release.

Finally, the end surface of the summer brick is smeared with adhesive mastic with a layer of 2-4 mm, and the outer surface of the welded box is wrapped with refractory wool before installation in the niche of the summer wall. Adhesive mastic and refractory wool ensure tight joints and prevent liquid metal from leaking out of the furnace. A conical hole (tap hole) is drilled in the center of the flying brick.

The introduction of these devices allows you to put in the prepared niche of the summer wall of the furnace box with the summer brick located in it and makes it possible to replace the summer brick with the box with a new (spare) one. Replacing the summer brick in the box can be done after the molten metal is drained from the furnace and it is cleaned of slag. The process of replacing the flying brick inside the box with a spare one, also located in the box, together with the box takes 14-16 minutes.

Figure 1. Flying brick for slag tap hole.

Figure 2. Flying brick for a cast iron taphole.

Figure 3. Installation of summer bricks for cast iron tap holes.

Figure 4. Suggested summer brick.

Figure 5. Flying brick in the box.

6. Installation of summer brick in the niche of the summer wall of the furnace.

In the present invention, for the manufacture of blanks for summer bricks, a mullite compacted block MLSU with dimensions of 500 × 400 × 300 mm is used, the characteristic of which is shown in Table 2.

table 2 Characteristic of mullite sealing blocks МЛСУ Mass fraction of Al ₂ O ₃ ,%, not less 62 Mass fraction of Fe ₂ O ₃ ,%, no more 1,1 Open porosity,%, no more eighteen The apparent density, g / cm ³ , not less 2.5 Strength at compression, N / mm ² , not less 70 Softening start temperature, ° С, not lower 1520

As can be seen from tables 1 and 2, the mullite compacted block proposed for the manufacture of blank bricks 1 has more aluminum oxide Al ₂ O ₃ , less iron oxide Fe ₂ O ₃ . In addition, the open porosity is lower, and the compressive strength is 3.5 times greater and the temperature of the onset of softening is higher by 120 ° C than that of the prototype.

According to the above indicators, the material of the proposed as billet summer brick 1 block MLSU has significantly higher characteristics, therefore, made from the block summer brick 1 will have a longer life.

For the manufacture of summer bricks from the MLSU block, it is necessary to saw it on the larger side into three equal parts, thus obtaining three workpieces (taking into account the thickness of the saw blade) with dimensions of 164 × 400 × 300 mm. Next, a “grinder” in the end part of the blank brick 1 is perimeter sampled with dimensions of 20 × 20 mm. In the center of the blank of summer brick 1, a hole 2 (tap hole) with a size of 20 × 32 mm is drilled with a conical drill. Thus, it turns fly brick 1, having, Fig. 4, 2.52 times greater thickness than fly brick 1 of the prototype and, of course, a longer service life (durability).

In order to make the flying brick 1 “easily removable”, it must be placed in a box 3, which is welded to the size of the flying brick 1 from sheet steel 2 mm thick, FIG. 5.

Flying brick 1 is laid in a box 3 and fixed in it with a fixing frame 4, welded from an angle of 32 × 32 mm. The fixing frame 4 is welded to the box 3, and also welded to the four stops 5. The latter are welded to the frame of the box 6, welded from an angle of 45 × 45 mm.

Three brackets 7 with grooves for fixing are welded to the frame of the box 6 at an angle of 120 °.

Three brackets 9 with grooves for fixing are welded to the armor of the furnace 8, Fig.6, at an angle of 120 °, and the grooves of the brackets 9 on the armor 8 of the furnace and on the frame of the box 6 are the same.

To fix the box 3 with the flying brick 1 located in it in the recess of the furnace wall 10 of the furnace, three clamping wedges 11 are used, which are included in the grooves of the bracket 7, welded to the frame of the box 6, and the grooves of the bracket 9, welded to the armor 8.

The retention system of the duct 3 with the summer brick 1 in it in the niche allows safe release of the summer brick 1 along with the duct 3 when it is replaced in case of wear and the formation of large cracks in it.

This is achieved through the use of inexpensive refractory mullite-siliceous wool 12 grade MKRR-130 of the Aprelevka plant (located in the village of Aprelevka), adhesive mastic, which ensures tightness and at the same time the ability to remove box 3 with summer brick 1 from the niche of the summer wall 10. The adhesive mastic was developed by the authors and has the following composition: fireclay powder - 40%, ground clay - 33%, technical lignosulfanate - 6%, phosphon - 2%, quartz sand - 7%, mortar MSH - 39-12%. The components of adhesive mastic are thoroughly mixed and diluted with water until the density of liquid sour cream. When lining the summer wall 10 of the furnace, a niche of rectangular shape with dimensions 10-15 mm larger than the dimensions of the box 3 is laid out. In the upper part, the niche is blocked by fireclay plate 13.

Two hooks 14 are welded to the frame of the box 6 on both sides to remove the box 3 with a worn-out summer brick in it. Before installing summer brick 1 in the duct 3 for sealing the lining and summer brick 1, its end surface B must be greased with a 2-4 mm layer of adhesive mastic.

A duct 3 with a fixed summer brick 1 is inserted into the niche of the summer wall 10. Previously, the outer surface of the duct 3 with the summer brick 1 inside it is wrapped with refractory wool 12, Fig.6, which provides low thermal conductivity and the possibility of excavation of the duct 3 when the summer brick 1 is destroyed. The remaining small gap between the box 3 and the niche is filled with the same refractory wool stuffed with a spatula.

In conclusion, it should be noted that the box 3 is fixed in the furnace niche with three clamping wedges 11, which are clogged by working smelters. Due to the use of adhesive mastic, the leakage of liquid metal between the niche and the wrapped refractory wool 12 box 3 does not occur.

Thus, the installation and fixing operation of the duct 3 with the flying brick inside it in the furnace niche is completed.

To remove the worn-out summer brick 1 together with the box 3 from the furnace niche, the working smelter, with a sledge hammer, knocks out three clamping wedges 11 in turn, then puts a rope on two hooks 14 of the box frame 6 and the loader easily removes the box 3 with the flying brick 1 in it from the niche.

In place of the worn-out summer brick 1 with a box 3, a new box 3 with a summer brick 1 inside is placed with two working smelters in the furnace niche, and the end face B of which is preliminarily lubricated with a 2-4 mm layer of adhesive mastic.

As a rule, spare summer bricks 1 in the box 3, wrapped with refractory wool, are stored in boxes or on racks in the pantry. According to practical data, the operation of replacing the old flying brick 1, located in the box 3, with a new one takes 14-16 minutes in time. It is significant to note that to drain metal from the furnace through the notch of the summer brick 1, it is necessary to attach a movable chute to it (not shown in the sketch).

The operation to replace the old worn summer brick takes place without stopping the furnace after pouring liquid metal and cleaning the furnace from slag.

The use of the proposed "easily removable" flying bricks of increased resistance, made of blocks of MLSU in the designs of shaft furnaces, increases their reliability and gives a great economic effect.

In order to replace factory-made summer bricks in the event of wear (bumps, cracks, destruction of the walls of the groove), you must stop the furnace, cool the lining (depending on the capacity of the furnace, the cooling time is 2-4 days), partially disassemble the two walls of the furnace and almost completely wall, replace the old flying brick with a new one, lining the walls again, calcine the furnace and resume melting.

The works described above are very laborious and require (depending on the capacity of the furnace) 6-10 days.

From the above it is seen what significant losses enterprises suffer because of the low resistance of the flying bricks, the impossibility of rapid replacement if worn.

Claims (2)

1. A cast iron notch of a furnace, in particular a mine, containing a flying brick, a flying wall with a niche, furnace armor, characterized in that the flying brick is made of a mullite compacted block with dimensions of 164 × 400 × 300 mm, placed in a welded box and fixed in it a fixing frame welded to the weld box and attached to four stops located in the corners of the weld box for additional fixation and holding the summer brick from the pressure of molten metal, while a frame with two welded to the front of the weld box three brackets are welded with knobs for removing worn-out summer bricks along with the welded box, as well as to the frame of the welded box, located at an angle of 120 °, in which grooves are made for clamping wedges, and three brackets are welded to secure the welded box in the recess of the summer wall to the furnace armor at an angle of 120 ° with grooves for clamping wedges, coinciding with the grooves of the brackets welded to the frame of the welded box. 2. The cast iron notch according to claim 1, characterized in that the end surface of the summer brick is smeared with adhesive mastic with a layer of 2-4 mm, and the outer surface of the welded box is wrapped with refractory wool before installation in the niche of the summer wall.

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