RU2356871C2 - Refractory mixture for iron notches of blast furnace - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: invention relates to refractories industry, particularly to receiving of mixtures, providing for overlapping of iron notches of blast furnaces. Refractory mixture for iron notches of blast furnaces contains coke, clunch and high-temperature peck at following components ratio, wt %: coke 42-58, clunch 26-41, high-temperature peck, containing 43 -54% of volatile, 16-17. Breakup of the received mixture is following, %: fraction more 3 mm - no more 25, fraction less 0.5 mm - no less 50, fraction less 0.09 mm - no less 40, refractory property - no less 1580°C, and humidity 12-20%.

EFFECT: improvement of running ability of mixture and external environment of furnace.

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Description

The invention relates to the refractory industry, and in particular to the production of masses intended for cast iron notches of blast furnaces.

Known, selected as a prototype, the refractory mass for cast iron notches of blast furnaces [1], including coke, refractory clay and high-temperature pitch, in which high-temperature pitch contains volatile not more than 43%.

Significant disadvantages of this refractory mass are:

- the high cost of the resulting mass in connection with the high cost of high-temperature pitch with the characteristics presented;

- low resistance of the refractory mass during the production of cast iron, due to the volatile content in the high-temperature pitch is not more than 43%.

Also known is a refractory flying mass [2] containing ground coke, refractory clay and coal tar, in which coal tar is used with a coke number of 25-28% in the following ratio of components, wt.%:

Fire-clay 15-20 Coal tar 20-30 Coke (fractions - 2 mm) rest

The significant disadvantages of this refractory fly weight are:

- low resistance of the refractory mass due to the selected ratio of components and the absence of high-temperature pitch in the composition;

- the high cost of the resulting mass due to the complexity of its manufacture.

The desired technical results of the invention are:

- improving the operational properties of the mass;

- reduction in the cost of cast iron.

To do this, we propose a refractory mass for cast iron notches of blast furnaces containing coke, refractory clay and high-temperature pitch, in which high-temperature pitch contains volatile 43-54%, in the following ratio, wt.%:

Coke 42-58 Refractory clay 26-41 High temperature pitch 16-17

moreover, the content of fractions of the resulting mixture should be,%:

fraction more than 3 mm, no more 25 fraction less than 0.5 mm, not less fifty fraction less than 0.09 mm, not less 40

The claimed limits are selected experimentally.

Coke is introduced into the composition to reduce the shrinkage of the mass, and when going beyond the declared limits, the shrinkage increases.

Refractory clay is introduced into the composition of the mass, as a material that prevents the mass from burning at the time of cast iron production, and when using less than 26%, the refractory characteristics of the mass sharply decrease, and with an increase of more than 41%, ductility decreases and emergency situations occur.

High-temperature pitch is introduced into the composition of the mass as a refractory plasticizer, and when using less than 16%, it is not possible to obtain the required ductility of the mass, and with an increase of more than 17%, the cost of the resulting material increases sharply. The volatiles content in the high-temperature pitch is selected based on the optimal amount, and when going beyond the declared limits, additional costs for its preparation are required.

The content of fractions of the resulting mixture was selected based on the fact that with an increase in the content of the fraction of more than 3 mm above 25%, it causes a sharp decrease in the resistance of the refractory mass. The decrease in the content of the fraction of less than 0.5 mm less than 50% causes a sharp increase in the duration of the solidification of the refractory mass in the channel of cast iron notches of blast furnaces. A decrease in the fraction content of less than 0.09 mm less than 40% causes a decrease in the ductility of the refractory mass.

The inventive refractory mass was made of the following materials:

Coke: ash no more than 18%; moisture no more than 20%; mass fraction of a piece of size more than 25 mm no more than 10%; mass fraction of a piece of size less than 10 mm is not more than 13%.

Refractory clay: refractoriness not less than 1670 ° С; moisture no more than 18%; mass fraction of Al ₂ O ₃ per calcined substance is not less than 30%.

High temperature pitch: no more than 0.4% ash; moisture (for pitch in the solid state) not more than 3%; softening temperature 135-150 ° C, 43-54% volatile.

The manufacture of the inventive refractory mass was carried out by mixing the components in the indicated proportions, blasting the resulting mixture with steel rollers to achieve fine grinding of the mixture and, further, the components were finally mixed through the mixer.

The inventive refractory mass (the compositions and characteristics of the components are shown in tables 1-4) were used on blast furnaces with a volume of 1310 m ³ and 1719 m ³ as a material for closing cast-iron notches of blast furnaces and for the manufacture of cases. This made it possible to improve the operational properties of the furnace, in particular, to reduce consumables and improve the working conditions of the maintenance personnel in connection with the easy removal of hardened clay mechanically from the duct of cast iron notches and during the repair of cases of cast iron notches with a decrease in its consumption by 0.002 kg / t of cast iron, and how consequence, reduce the cost of pig iron by 3.3 rubles / ton.

Table 1 Components The composition of the refractory mass,% No. 1 Number 2 Number 3 Number 4 Coke 42 fifty 54 58 Refractory clay 41 34 29th 26 High temperature pitch 17 16 17 16

table 2 Components Component Feature Ash% Moisture% Mass fraction of a piece of size over 25 mm,% Mass fraction of a piece of size less than 10 mm,% Coke; composition 1 11,2 5.8 9.9 8.5 composition 2 13.1 10.1 9.6 11.3 composition 3 16,0 14.2 8.8 10,2 composition 4 17.9 19.8 8.7 13.0

Table 3 Components Component Feature Refractoriness, ° С Moisture% Mass fraction of Al ₂ O ₃ per calcined substance,% Refractory clay; composition 1 1750 18.0 32,5 composition 2 1720 16,4 36,4 composition 3 1670 14.2 38.7 composition 4 1800 10,2 30.1

Table 4 Components Component Feature Ash% Moisture% Softening point 135-150 ° C, Volatile% High temperature pitch; composition 1 0.2 2,8 143 43 composition 2 0.1 3.0 150 48 composition 3 0.3 2.2 135 54 composition 4 0.4 1.8 140 51

Information sources

1. AS of the USSR No. 405837, class C04B 25/02, C04B 35/52.

2. USSR AS No. 592790, class C04B 25/02, C04B 35/52.

Claims (1)

Refractory mass for cast iron stove blast furnaces, containing coke, refractory clay and high-temperature pitch, characterized in that the high-temperature pitch contains volatile 43-54% in the following ratio of components, wt.%:
Coke 42-58 Refractory clay 26-41 High temperature pitch 16-17
moreover, the content of fractions of the resulting mixture should be,%:
fraction over 3 mm no more than 25 fraction less than 0.5 mm not less than 50 fraction less than 0.09 mm not less than 40