RU2188179C2 - Refractory body for plugging of blast-furnace tapholes - Google Patents

Abstract

FIELD: compositions of refractories, particularly, refractory bodies for stopping of pig iron tapholes of blast furnaces. SUBSTANCE: refractory body contains, mas.%: grog, 10-15; fireclay, 18-23; ground coke, 33-38; polymerized wash oil, 20-25; pitch-like product, 8-13. Pitch-like product is obtained by mixing of coal organic mass with fraction of coals tar in presence of iron components as catalysts, heating of mixture up to 300-400 C and dwelling under pressure of own gases. EFFECT: production of refractory body with optimal properties, low cost and harmless for ecology. 2 tbl

Description

 The invention relates to compositions of refractory materials, in particular to refractory masses for incorporating tap holes of blast furnaces.

Known flight weight containing, wt.%:
Coke pitch electrode fraction less than 10 mm - 52 - 61
High temperature coal tar pitch - 14 - 16
Refractory clay - 20 - 22
Organic Resin - 5 - 10
(A. p. 833866, M.C. ³ C 04 B 35/54, 1979).

 Known flying mass has insufficient ductility and resistance to molten metal, slag; it is carcinogenic due to the presence of high-temperature coal tar pitch and the road is due to the high content of pitch coke in it.

Known refractory mass for sealing letok blast furnaces containing ground coke, refractory clay, high-temperature coal tar pitch, fireclay powder, polymerized absorption oil in the following ratio of components, wt.%:
Refractory clay - 20 - 25
High temperature coal tar pitch - 5 - 10
Fireclay powder - 10 - 15
Polymerized Absorption Oil - 16 - 20
Ground Coke - Rest
(A. p. 1224339, M.C. ⁴ C 21 B 7/12, 1986).

 This flying mass contains an expensive and carcinogenic component - a high-temperature coal tar pitch.

 The objective of the invention is to create an environmentally friendly refractory mass for sealing tap holes of blast furnaces with optimal properties and low cost.

The task is achieved in that the refractory mass for sealing the sockets of blast furnaces, including fireclay powder, refractory clay, ground coke, polymerized absorption oil and sintering component, according to the invention as a sintering component contains a pitch-like product in the following ratio of components, wt.%:
Fireclay powder - 10 - 15
Refractory clay - 18 - 23
Ground coke - 33 - 38
Pitch-like product - 8 - 13
Polymerized absorption oil - 20 - 25
The invention consists in the following. The proposed flying mass is obtained by dosing the components and mixing until a homogeneous plastic mass is obtained. The use of an environmentally friendly pitch-like product as a sintering component as a sintering component, which, due to the formation of a carbon skeleton during firing, binds all the components of the mass, provides an increase in its mechanical strength by 50-60% with optimal (5-9%) volume expansion.

A pitch-like product is obtained by mixing the organic mass of coal with a coal tar fraction in the presence of a catalyst (iron compound). The mixture is heated to 300-400 ^o C and maintained under pressure of its own gases. The resulting pitch-like product is similar in properties to high-temperature pitch, but contains less toxic polyaromatic hydrocarbons. Softening point 134-145 ^o C; yield of volatiles 61.1-62.7%; the amount of substances insoluble in quinoline, 16.6-31.6%.

 When the content of the pitch-like product in the mass is less than 8%, the mechanical strength, slag resistance of the mass, its volumetric growth decreases, which leads to incomplete filling of the notch channel.

 An increase in the content of the pitch-like product in the mass of more than 13% is undesirable, because it is also necessary to increase the content of polymerized absorption oil above 25%, which is a solvent for the pitch-like product, and therefore, to reduce the content of refractory clay, which ultimately leads to a decrease in the plasticity of the mass.

 When the coke content in the mass is less than 33%, its gas permeability and non-wettability by cast iron and slag are reduced.

 With an excess of coke in the mass (more than 38%), its strength and ductility decreases due to an increase in porosity, which makes it difficult to uniformly fill the notch channel.

 Refractory clay plays the role of a binder in the mass, therefore, when the content of clay in the last clay is less than 18%, the mass density decreases, its friability increases, ductility decreases, therefore, difficulties arise when sealing a notch of a blast furnace.

Refractory clay containing Al ₂ O ₃ , SiO ₂ and other minerals, during annealing, shrinks due to chemical transformations. Shrinkage of the mass leads to the formation of cracks, a decrease in strength, so an increase in clay content of more than 23% is impractical, because the speed of the hot air channel rises during the production of cast iron, which can lead to an emergency.

When the content of chamotte powder is less than 10% in mass, it is necessary to increase the clay content, and since it has components similar to chamotte powder: Al ₂ O ₃ , SiO ₂ , mullite, etc., therefore, the strength, heat resistance of the mass decreases, fracture increases, and the rate of burnout of the flight channel increases.

 The content of chamotte powder in the mass of more than 15% is undesirable, because its ductility and gas permeability are reduced.

 The content in the mass of polymerized oil less than 20% leads to a decrease in its ductility, which makes it difficult to fill the channel of the notch of the blast furnace.

 An increase in the content of polymerized absorption oil in the mass above 25% is undesirable due to a significant increase in ductility, a sharp decrease in mechanical strength at high temperature due to the release of volatile from the oil and the formation of pores in the mass.

 Example. A refractory mass for sealing up the notches of blast furnaces of the claimed composition was prepared as follows. Powdered coke 36%, fireclay powder 13%, refractory clay 22%, pitch-like product 9% were loaded into runners and mixed. The prepared mixture was loaded into the mixer, after which 20% of the polymerized absorption oil was added to the mixture and mixed until a homogeneous plastic mass was obtained.

The test results of the various compositions of the refractory mass for sealing the notches of blast furnaces are summarized in table. 1, 2. Tests have confirmed that the masses prepared from components, the amount of which is taken within the claimed limits, have optimal properties (strength 30-45 kg / cm ² , volumetric growth 5-15%, ductility 2.6-8%).

 Practical data proved that the ratio of the components in the preparation of the mixture of the proposed mass can be varied over a fairly wide range while maintaining the required properties. Changing the content of components beyond the claimed limits is undesirable (see tab. 1, 2), because refractory masses with worse properties are obtained.

 The proposed refractory mass is industrially applicable in metallurgy, specifically - for closing up notches of blast furnaces.

Claims (1)

Refractory mass for sealing up the notches of blast furnaces, including fireclay powder, refractory clay, ground coke, a polymerized absorption oil and a sintering component, characterized in that as a sintering component it contains a pitch-like product obtained by mixing the organic mass of coal with a fraction of coal tar in the presence of iron compounds as a catalyst, heating the mixture to 300-400 ^o C and exposure under pressure of its own gases in the following ratio of components, mass, wt.%:
Fireclay powder - 10 - 15
Refractory clay - 18 - 23
Ground coke - 33 - 38
Polymerized absorption oil - 20 - 25
The specified pitch-like product - 8 - 13s

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