RU1795983C - Method of performing rammed lining of runners of blast furnace - Google Patents

Abstract

SUMMARY OF THE INVENTION: in a method for stuffing a lining of a gutter of a blast furnace, including preparing a refractory mass, laying it in the bottom, and then in the walls of the gutter, vibration sealing and ramming to give a predetermined geometric shape, after laying the refractory mass, the bottom of the gutter is formed by additionally adding graphite fractions, pre-coated at a temperature of 250 ... 300 ° C with a tar pitch film to a thickness of 0.35 ... 0.50 mm. wherein the height of the bed is 1/3 of the height of the stuffed lining of the bottom of the gutter. 1 tablet, 1 ill.

Description

The invention relates to metallurgy, in particular to the production of iron, cast iron and steel, and can be used in the metallurgical industry for the construction of blast furnaces.

A known method of making a printed lining of the trough of a blast furnace, comprising preparing a refractory mass, its laying in the bottom, and then in the walls of the gutter, vibration compaction and ramming with giving a given geometric shape (1).

A disadvantage of the known method is the low working life of the gutter. This is explained by the fact that jets of liquid metal and slag under the influence of high temperatures have a destructive effect on the trough, for example, they carry away volatile and leach solid components of the lining.

The purpose of the invention is to increase the working life of the gutter.

This goal is achieved in that a method of performing a printed lining of the trough of a blast furnace, comprising preparing a refractory mass, laying it in

the bottom, and then into the walls of the gutter, vibration compaction and tamping to give the desired geometric shape, according to the invention, after laying the refractory mass, the bottom of the gutter is formed by additionally adding graphite fractions pre-coated at a temperature of 250 ... 300 ° C with a coal tar film to a thickness of 0 , 35 ... 0.50 mm, where the height of the bedding is 1/3 of the height of the stuffed lining of the bottom of the gutter.

The technical solution provides for the implementation of a printed lining consisting of a refractory cushion and a cementitious bedding based on graphite fractions and coal tar pitch, laid on the most loaded section - in the bottom of the gutter of a blast furnace. The molding of the bottom of the gutter, for example, by adding graphite fractions, after laying the refractory mass, provides high adhesion and density of the components of the stuffed lining ..

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Physical impact on coal tar pitch and graphite, as material objects with high binder and heat insulating properties, allows us to exhibit a supertotal effect aimed at increasing the working life of the gutter. So, graphite fractions before vibration compaction are covered with a film of coal tar pitch to a predetermined thickness, in particular 0.25 ... 0.50 mm, and coal tar pitch (before application) is subjected to heat treatment - it is liquefied at Т 250-300 ° С, well above melting point. Coating the graphite fractions with a pitch film eliminates supersaturation of the mass with excess, thickness variation, the accumulation of which in the gaps between the fractions of graphite is prone to burnout and entrainment due to insufficient bonding. refractory mass. It is the impact on the graphite with a pitch film before vibration compaction that reduces the influence of temperature and mechanical aggression from the side of liquid slag and metal, because the proposed coating allows isolating the refractory mass from them and activating the adhesion of the components of the printed lining.

. The use of another material instead of coal tar pitch restrains the achievement of the goal.

Achieving this goal is impossible without the conditions for performing operations on coal tar pitch and graphite. In particular, coating graphite fractions with a film of coal tar pitch with a thickness of less than 0.35 mm is impractical. This is because, at lower film thicknesses, the adhesion of the cementitious bedding with the refractory mass of the trough pad decreases. An increase in the thickness of the pitch film of more than 0.50 mm is also impractical. This is explained by an increase in the porosity of the cementing layer, the content of excess pitch in the gaps between the fractions of graphite, and the yield of volatile components, which together reduces the cementation effect of the printed lining. At the same time, the coating of graphite fractions with coal tar pitch (or thinning the pitch) at T 250 ... 300 ° C allows the latter to exhibit an over-total effect aimed at increasing the working life of the blast furnace trough. This is due to the fact that at T 250 ... 300 ° C significantly higher than T melting, the pitch turns into a fluidized state. In this state, coal tar pitch, as a component with high binder and refractory characteristics, diffuses the crystal lattice of graphite, penetrating as a large depth of the structure, thereby exhibiting the property of a coagulant. This, in view of bringing graphite to fractional dimensions to a large approximation, contributes to its deep impregnation, and after vibration compaction and tamping, to clogging the pitch in the bedding and to significantly reduce the entrainment of volatile ingredients. The result of the interaction of fractions of graphite and

0

coal tar pitch is getting

cementing layer of high temperature power, preventing thermal and mechanical aggression from the jets of metal and slag in the gutter,

5 achieved by the new property of coal tar pitch. Coating graphite fractions with coal tar pitch at T less than 250 ° C is impractical. This is due to a decrease in cohesive and cohesive

0 pitch properties. Coating at a liquefaction temperature of pitch exceeding 300 ° C is also impractical. This is explained by the increased evaporation of the pitch, which reduces its thermophysical properties and

5 increases the fluidity, reducing the possibility of achieving a uniform film coating of graphite, its thickness variation and, consequently, uneven cementation of the printed lining develops.

In addition, the height of the bedding according to the invention is 1/3 of the height of the stuffed lining of the bottom of the gutter. Deviation of the bedding height from a given value5 is neither impractical. This is explained by the fact that when the filling height is less than 1/3 of the height of the packed lining, the cementation efficiency decreases, since the likelihood of washing the lining with jets increases

0 molten metal and slag. When the height of the bedding exceeds 1/3 of the height of the packed lining, the power of its refractory layer decreases, the likelihood of destruction of the cementing bedding due to the accelerated burning of graphite and the entrainment of volatile components of the coal tar pitch increases.

The drawing shows a longitudinal section of the trough of a blast furnace.

0 The gutter contains a bottom 1, side walls 2 lined with refractory bricks and an outer shell 3. The bottom 1 and side walls 2 are saturated with refractory mass 4, which forms the basis of the printed lining. AT

On bottom 5, cementing bed 5 is placed on top of the refractory mass 4 on the basis of graphite fractions and coal tar pitch, with a height Hi corresponding to 1/3 of the height. On the printed lining 6 of the bottom 4 of the gutter.

For the manufacture of the proposed blast furnace chute, the starting refractory mass is loaded from volumetric batchers into working runners of type CH567, which is mixed with a bucket elevator. The lining mass has the following composition, May. %:

Blast furnace coke 24.5-29.5 Coal tar pitch 11.0-16.0 Clay refractory 17.5-20.5 Carbon-containing material (1C) 36.5-44.5 Moisture 10-14 Blast furnace coke, grade 25-40 mm meeting TU 14-6-1114-75. Coal tar pitch - high temperature with a softening T of 140-160 ° С, corresponding to TU-14-6-153-76. The clay is refractory to the Chasov-Yarskoye field of grade 4-1, ChPK-1, meeting TU 14-8-162-75. The carbon-containing material is C-heat treated (C - 25 + 45%, CO2 - 10 + 20%), fractions - up to 20 mm.

The resulting refractory mass 4 is conveyed into the gutter forming zone by means of a conveyor and laid in bottom 1, in particular until 2/3 of the height H2 of the packing lining of the bottom 1 of the gutter is filled. Then, a section of the bottom 1 of the trough is formed, which is in contact with jets of metal and slag, by uniformly adding 5 graphite fractions pre-coated with a film of coal tar pitch to a height Hi corresponding to 1/3 of the height H2 of the printed liner H2. Dimensions of graphite fractions 100 ... 150 mm, pitch film thickness 0.35 ... 0.50 mm. A pitch film is applied at a liquefaction temperature of 250 ... 300 ° C. After that, the height of the side walls 2 and the bedding material 5 is increased. Then, for 15-20 minutes, the preformed mass is vibro-absorbed and rammed to its final shape and fired. In the future, use a pipe with a diameter of 1/211 with 3-4 mm perforation as a nozzle to the gas burner while continuing firing. Firing is carried out for 7-8 hours, isolating the gutter with metal sheets. Using probes during tamping, heights W and H2 and the thickness of the trough are controlled. After firing, the calcination uniformity is checked. Shrinkage, local damage and cracks are repaired with a coating based on refractory mass 4. The geometrical shape of the gutter is achieved using patterns.

For experimental verification of the claimed method, the technological modes of processing graphite were tested.

fractions and the height of the bed of filling in the printed lining of the gutter.

The test results are shown in the table.

5 In the study of the claimed method, 90 processing options for graphite fractions were analyzed, which are summarized in the attached table. The table informs that 9 of them have optimal

0 result and indicates the achievement of the goal. Optimal results correspond to 7, 8, 9 series of experiments. Some mixtures, for example, those obtained in 3 and 13 series of 5 x, also increased the gutter's working life, in particular, to 9 and 10 days, respectively, but they are not sufficiently effective in comparison with the noted results. Tests performed inform

0 that after coating graphite fractions with coal tar pitch, in particular, with a film to a thickness of 0.35 ... 0.50 mm at T 250 ... 300 ° C and laying a sprinkle to a height corresponding to 1/3 of the height of the stuffed bottom lining gutters, the working life of the gutter of a blast furnace increases to .12 ... 15 days.

Comparison of the claimed method with the prototype shows that the combination

0 of the proposed differences allows to obtain an effect aimed at increasing the working life of the gutter. This is due to the additional use of graphite bedding, pre-treated

5 by coal tar pitch, in particular, at a temperature conducive to the conversion of the latter to the fluidized state and coagulation into the structure of graphite. This made it possible to increase the resistance of the refractory lining to temperature and mechanical aggression of jets of metal and slag - to increase the working life of the gutter from 8 to 12 ... 15 days, by increasing the density and heat resistance of the stuffed lining. This is due to

5 by reducing the volatility of the volatiles, porosity and leaching of the solid components of the lining. A pitch film on a graphite surface deposited at Т 250 ... 300 ° С to a thickness of 0.35 .., 0.50 mm improves the adhesion of the lining components, impermeability, and gives the cementing layer of the backfill super-total properties.

ABOUT

Using the proposed method 5 for the construction of blast furnaces will further improve the environment by reducing emissions of toxic aerosols into the atmosphere; Reduce blast furnace downtime increase the reliability of the gutter.

Claims (1)

SUMMARY OF THE INVENTION A method for making a stuffed lining of a gutter of a blast furnace, including preparing a refractory mass, laying it in the bottom, and then in the walls of the gutter, vibration-sealing and tamping to give a predetermined geometric shape, characterized in that, in order to increase the working life of the gutter, after laying the refractory mass, the bottom of the gutter is formed by additionally adding graphite fractions precoated at a temperature of 250-300 ° C with coal tar film to a thickness of 0.35-0.50 mm, and the height of the bedding is 1/3 of the height of the packed lining bottom of the gutter.