RU2239612C1 - Refractory concrete mix (versions) - Google Patents

Abstract

FIELD: manufacture of refractory materials; corundum low-cement hydraulically hardening masses; manufacture of monolithic linings for high-temperature thermal units.

SUBSTANCE: proposed refractory concrete mix contains, mass-%: grain synthetic corundum of fraction 6-3 mm, 15-22; fraction 3-1 mm, 8-20; fraction 1-0 mm or mixture of fraction 0.5-0 mm and 1-0.5 mm, 13-27; silicon carbide, 13-27; finely dispersed corundum, 14-24; high-alumina cement, 7-16 and plasticizing additive, 0.03-0.55. According to second version concrete mix contains, mass-%:grain synthetic corundum of fraction 3-1 mm, 28-42; or mixture of fraction 6-3 mm, 17-25 and fraction 3-1 mm, 27-33; fraction 1-0 mm,18-42; finely-dispersed sludge of synthetic corundum of fraction -5- mcm, 5-10; tabular corundum of fraction -20 mcm, 14-17; high-alumina cement, 6-8 and plasticizing additive, 0.03-0.55. According to third version, concrete mix contain, mass-%: grain synthetic corundum of fraction 3-1 mm, 18-40; or mixture of fraction 6-3 mm in the amount of 18-25 and fraction 3-1 in the amount of 18-32; fraction 1-0.5 mm, 9-42; finely-dispersed synthetic corundum of fraction <63 mcm, 30-35; high-alumina cement, 7-9 and plasticizing additive, -0.2-0.3. Sodium tripolyphosphate, mixture of soda ash and sodium lignosulfonate, mixture of boric acid, citric acid, soda ash and lithium carbonate, mixture of citric acid, soda ash and lithium oxide or organic fiber may be used as plasticizing additive.

EFFECT: enhanced slag resistance and ultimate strength at compression after drying.

16 cl, 8 tbl

Description

The invention relates to the production of refractories, in particular, low-cement corundum hydraulically hardening masses and can mainly be used in metallurgical, heat power, chemical, construction and other industries for the manufacture of monolithic linings of various high-temperature thermal units, for example, monolithic bottoms of steel pouring ladles, blast chutes furnaces, tuyeres for purging metal of arc steel-smelting furnaces and branch pipes of out-of-furnace treatment plants and in the steel industry.

Monolithic linings used in metallurgy are used, as a rule, in conditions of extremely high temperatures reaching 1600 ° C and more, due to contact with molten metals and slags. Therefore, the quality of monolithic linings is determined, first of all, by the values of physical and mechanical properties that they acquire during operation at such high temperatures.

Known corundum hydraulically hardening mass grade MKN-94 (Refractories for vacuum metallurgical units. M: Metallurgy, 1982, p. 92, table 34), widely used for the manufacture and repair of linings of steel after-treatment plants and containing electrocorundum and high-alumina cement. However, refractories made from the specified mass after firing at a temperature of 1600 ° C have a low compressive strength not exceeding 20 N / mm ² and a sufficiently high open porosity of about 32%. With the indicated open porosity of the refractory, it is impregnated with molten metal and slag, which leads to the destruction of the lining. This process proceeds even more intensively in the case of a low value of compressive strength of a monolithic lining.

Improvements to the indicated physical and mechanical indicators are achieved by introducing titanium-containing additives into corundum hydraulically hardening masses.

The following types of titanium-containing corundum hydraulically hardening masses are known:

hydraulically hardening titanium-containing corundum masses of the MKTN-1 and MKTN-2 grades (Refractories for vacuum metallurgical units. M .: Metallurgy, 1982, p. 92, table 34), containing white alumina and high alumina cement with the addition of titanium corundum and titanium dioxide, respectively . Refractories of these known masses after firing at a temperature of 1600 ° C have a compressive strength of about 35 N / mm ² and an open porosity of 30% and 28%, respectively;

hydraulically hardening corundum mass (SU 1678808, 1991), containing high alumina cement in an amount of 13-20 wt.%, titanium slag in an amount of 0.8-3.0 wt.% and electrocorundum (the rest). After firing at a temperature of 1600 ° C, refractory linings made from this mass have a compressive strength of 43.0-47.1 N / mm ² and open porosity in the range of 22.5-23.2%;

hydraulically hardening corundum (RU 2098386, 1997), which contains high alumina cement in an amount of 13-20 wt.%, ilmenite concentrate as a titanium-containing additive in an amount of 0.7-3.0 wt.% and electrocorundum (the rest) and allows to obtain refractory linings having, after firing at a temperature of 1600 ° C., a compressive strength equal to 57.8-69.4 N / mm ² and an open porosity in the range of 18.4-19.0%.

However, the above values of the physico-mechanical properties of refractories obtained from these hydraulically hardening masses are, in some cases, far from sufficient. In addition, a sufficiently high percentage in all of the above hydraulically hardening masses of high alumina cement as a hydraulic binder, on the one hand, provides the above strength characteristics of the obtained refractories both on the raw material and after drying and calcination, but, on the other hand, leads to reduce heat resistance, expressed in lowering the temperature of deformation under load and increasing changes in linear dimensions during drying and firing.

In this regard, low-cement refractory concrete mixtures with thixotropic properties have some advantages, which include a complex binder based on a mixture of high-alumina cement as a hydraulic binder and finely divided refractory material with plasticizing additives.

Accordingly, refractory concrete is known (DD 267387, 1987), containing a refractory filler based on alumina and as a complex binder a mixture of alumina cement, finely divided alumina, silica, magnesium oxide and a deflocculant. However, this refractory concrete has low metal and slag resistance due to high open porosity, insufficiently high compressive strength after firing, and a relatively low operating temperature not exceeding 1450 ° C.

The closest in composition and physico-mechanical parameters to the proposed invention should be considered refractory concrete mix according to the patent of the Russian Federation No. 2140407, 1999, C 04 B 35/66, used for the manufacture of monolithic linings and shaped products of various thermal units. The specified refractory concrete mixture contains a refractory filler based on alumina, for example, sintered or electrofused granular corundum, bauxite or chamotte, and a complex finely dispersed binder comprising high alumina calcium aluminate cement, alumina or a mixture of alumina and silica, magnesia or alumina deflocculant as a plasticizing additive in the following ratio of components, wt.%: refractory filler fr. 7-3 mm 25-45, fr. 3-1 mm 15-35, fr. 1-0 mm 20-45, alumina or a mixture of alumina and silica fr. 6-0.1 μm 2-25, high-alumina calcium-aluminate cement fr. <40 μm 2-8, magnesium oxide or alumino-magnesian spinel fr. <20 μm 5-15 and deflocculant 0.1-1.5.

As follows from the examples given in the description of the invention to this patent, the specified refractory concrete mixture contains the following ratio of components, wt.%: Electrocorundum with an alumina content of at least 98% fr. 7-3 mm 35, fr. 3-1 mm 25, fr. 1-0 mm 21, ultrafine alumina powder fr. 6-0.1 microns 8, high alumina cement fr. <40 μm 5, magnesium oxide fr. <20 μm 5.5 and deflocculant 0.5, and when using 5.5 wt.% Mixing water (in excess of 100% dry weight of the mixture) provides refractories having a compressive strength of 17 N / mm ² and 87 N / mm ^2, respectively, after 5 hours of hardening (after drying) and after heat treatment at a temperature of 800-850 ° C, as well as slag resistance equal to 3 mm. These data indicate insufficient slag resistance of refractories and their ultimate compressive strength, especially after drying.

Therefore, the disadvantages of the known refractory concrete mixture selected for the prototype are insufficiently high slag resistance and low tensile strength in compression, especially after drying, refractories obtained on its basis.

The objective of the present invention is to increase slag resistance and compressive strength after drying of refractories, obtained on the basis of the proposed refractory concrete mixture.

The problem is solved according to the invention, firstly, the fact that the proposed refractory concrete mixture containing, in accordance with the prototype, granular electrocorundum and a complex fine-dispersing binder based on a mixture of high-alumina cement, fine aluminum oxide and plasticizing additives, differs from the prototype in that it contains silicon carbide and fine corundum as fine alumina in the following components, wt.%:

Granular Electrocorundum

fr. 6-3 mm 15-22

fr. 3-1 mm 8-20

fr. 1-0 mm or a mixture of fr. 0.5-0 mm and fr. 1-0.5 mm 13-27

Silicon Carbide 13-27

Fine corundum 14-24

High Alumina Cement 7-16

Plasticizing additive 0.03-0.55

In this case, the refractory concrete mixture contains silicon carbide fr. 1.6-1.25 mm, a mixture of granular electrocorundum fr. 0.5-0 mm and fr. 1-0.5 mm, taken in the ratio (0.8: 1.2) (1.2: 0.8), as fine-grained corundum sludge electrocorundum fr. -50 microns in an amount of 14-18 wt.% Or a mixture of electrocorundum sludge fr. -50 microns in an amount of 4-6 wt.% And tabular corundum fr. -20 microns in an amount of 16-18 wt.%, And as a plasticizing additive sodium tripolyphosphate in an amount of 0.45-0.55 wt.%, Or a mixture of soda ash in an amount of 0.15-0.25 wt.% And lignosulfonate sodium in an amount of 0.045-0.055 wt.%, or a mixture of boric acid in an amount of 0.015-0.025 wt.%, citric acid in an amount of 0.025-0.035 wt.%, soda ash in an amount of 0.005-0.015 wt.% and lithium carbonate in an amount of 0.001 -0.002 wt.%, Or a mixture of citric acid in an amount of 0.025-0.035 wt.%, Soda ash in an amount of 0.005-0.015 wt.% And lithium oxide in an amount of 0.001-0.002 wt.%.

The problem is solved according to the invention, and secondly, the fact that the proposed refractory concrete mixture containing, in accordance with the prototype, granular electrocorundum and a complex fine binder based on a mixture of high alumina cement, fine aluminum oxide and plasticizing additives, differs from the prototype in that it contains as a fine alumina a mixture of fine sludge electrocorundum FR. -50 microns and tabular corundum fr. -20 μm with the following components, wt.%:

Granular Electrocorundum

fr. 3-1 mm 28-42

or a mixture of fr. 6-3 mm 17-25

and fr. 3-1 mm 27-33

fr. 1-0 mm 18-42

Fine sludge electrocorundum fr. -50 μm 5-10

Tabular corundum fr. -20 μm 14-17

High Alumina Cement 6-8

Plasticizing additive 0.03-0.55

In this case, the refractory concrete mixture contains either sodium tripolyphosphate in the amount of 0.45-0.55 wt.%, Or a mixture of soda ash in the amount of 0.15-0.25 wt.% And sodium lignosulfonate in the amount of 0.045- as a plasticizing additive. 0.055 wt.%, Or a mixture of boric acid in an amount of 0.015-0.025 wt.%, Citric acid in an amount of 0.025-0.035 wt.%, Soda ash in an amount of 0.005-0.015 wt.% And lithium carbonate in an amount of 0.001-0.002 wt.% or a mixture of citric acid in an amount of 0.025-0.035 wt.%, soda ash in an amount of 0.005-0.015 wt.% and lithium oxide in an amount of 0.001-0.002 wt.%.

The problem is solved according to the invention, and thirdly, the fact that the proposed refractory concrete mixture containing, in accordance with the prototype, granular electrocorundum and a complex fine binder based on a mixture of high alumina cement, fine aluminum oxide and plasticizing additive, differs from the prototype in that that it contains, as a fine alumina, fine electrocorundum fr. <63 μm with the following content of components, wt.%:

Granular Electrocorundum

fr. 3-1 mm 18-40

or a mixture of fr. 6-3 mm 18-25

and fr. 3-1 mm 18-32

fr. 1-0.5 mm 9-42

Fine electrocorundum fr. <63 μm 30-35

High Alumina Cement 7-9

Plasticizing additive 0.2-0.3

In this case, the refractory concrete mixture contains organic fiber as a plasticizing additive.

Introduction to the composition of one of the options of the proposed refractory concrete mixture as a fine aluminum oxide of finely divided corundum with the following content of components, wt.%: Granular electrocorundum fr. 6-3 mm 15-22, fr. 3-1 mm 8-20, fr. 1-0 mm or a mixture of fr. 0.5-0 mm and fr. 1-0.5 mm 13-27, silicon carbide 13-27, fine-grained corundum 14-24, high-alumina cement 7-16 and plasticizing additive 0.03-0.55, when fused alumina slurry was used as fine-grained corundum. -50 microns in an amount of 14-18 wt.% Or a mixture of electrocorundum sludge fr. -50 microns in an amount of 4-6 wt.% And tabular corundum fr. -20 microns in an amount of 16-18 wt.%, And a mixture of granular electrocorundum fr. 0.5-0 mm and fr. 1-0.5 mm is taken in the ratio (0.8: 1.2) (1.2: 0.8), provides one version of the refractory concrete mixture with a rationally selected composition according to the size of the fractions and their percentage of such components of the mixture, as granular electrocorundum as a refractory filler and finely divided corundum as a component of a complex finely divided binder.

Introduction to the composition of the second version of the proposed refractory concrete mixture as a fine aluminum oxide mixture of fine sludge electrocorundum FR. -50 microns and tabular corundum fr. -20 μm with the following components, wt.%: Granular electrocorundum fr. 3-1 mm 28-42 or a mixture of fr. 6-3 mm in the amount of 17-25 and fr. 3-1 mm in the amount of 27-33, fr. 1-0 mm 18-42, fine sludge electrocorundum fr. -50 μm 5-10, tabular corundum fr. -20 μm 14-17, high alumina cement 6-8 and plasticizing additive 0.03-0.55, provides a second variant of refractory concrete mix with also a rationally selected composition according to the size of the fractions and their percentage of such components of the mixture as granular electrocorundum in as a refractory filler and finely divided corundum as a component of a complex finely divided binder.

Introduction to the composition of the third version of the proposed refractory concrete mixture as a fine aluminum oxide of fine electrocorundum fr. <63 μm with the following content of components, wt.%: Granular electrocorundum fr. 3-1 mm 18-40 or a mixture of fr. 6-3 mm in the amount of 18-25 and fr. 3-1 mm in the amount of 18-32, fr. 1-0.5 mm 9-42, fine electrocorundum fr. <63 μm 30-35, high alumina cement 7-9 and plasticizing admixture 0.2-0.3, provides a third variant of refractory concrete mixture with also a rationally selected composition according to the size of the fractions and their percentage of such components of the mixture as granular electrocorundum in as a refractory filler and finely divided corundum as a component of a complex finely divided binder.

Such a rational choice of the compositions of the variants of the proposed refractory concrete mixture was made by the inventors empirically and, according to their assumption, provides a more dense structural matrix made of a mixture of refractory. On the one hand, this reduces the open porosity of the refractory obtained from the mixture and, as a result, increases its metal and slag resistance, and, on the other hand, provides an increase in the compressive strength, primarily after drying the refractory, and, in some cases, after firing, including at a temperature of 1600 ° C.

In this case, the use of refractory concrete mixes as a component of a complex finely dispersed binder mixture of electrocorundum sludge fr. -50 microns and tabular corundum fr. -20 μm, the finely dispersed particles of which have a lamellar shape, according to the inventors, further contributes to a more dense structural matrix of the refractory and provides an increase in compressive strength, as well as a decrease in open porosity, leading to an increase in metal and slag resistance. In this case, the use of sludge electrocorundum FR. -50 μm, which is a waste of corundum production and therefore having a low cost, allows you to get a refractory concrete mixture with a relatively small percentage (up to 18 wt.%) Having a high cost of tabular corundum fr. -20 microns or no content of the latter This, on the one hand, does not cause a significant increase in the cost of the proposed refractory concrete mix, and on the other hand, does not lead to a noticeable decrease in the heat resistance of refractories made on its basis.

The introduction of one of the variants of the proposed refractory concrete mixture of silicon carbide, for example silicon carbide FR. 1.6-1.25 mm, leads, firstly, to an increase in the metal and slag resistance of the refractories obtained from it due to the low adhesion ability of silicon carbide to metals and slag and, secondly, to an increase in their heat resistance, characterized by the number of heat exchanges up to the appearance of cracks or destruction of the refractory.

At the same time, the use of the above fractions in the complex finely dispersed binder of finely dispersed corundum together with the use of the plasticizing additives listed above made it possible to keep the percentage of high-alumina cement as a hydraulic binder insignificant and therefore prevent a decrease in the deformation temperature under the load of the resulting refractories and not only save but also increase the limit compressive strength after drying the refractory. The same reason made it possible to practically not increase the amount of mixing water used for the proposed refractory mixture in comparison with the prototype, which did not lead to an increase in the open porosity of the obtained refractories and therefore contributed to an even greater increase in metal and slag resistance.

The use in the third embodiment of the proposed refractory concrete mixture as a plasticizing additive of organic fiber, as the authors of the invention suggest, also helps to increase metal and slag resistance after firing the refractories obtained from it. This is probably due to the fact that during firing as a result of burning of the smallest organic fibers in the surface layer of the refractory, the thinnest capillary deadlock channels are formed, penetrating the refractory volume to an extremely shallow depth. Upon contact of the refractory with molten metal or slag, the smallest particles of metal or slag penetrate only into these capillary channels, but to a very small depth, and do not go deep into the volume of the refractory, which ensures an increase in metal and slag resistance.

The indicated qualitative and quantitative ratios of the components of the variants of the proposed refractory concrete mixture were obtained experimentally by the inventors and are most acceptable, since when the claimed ranges of the quantitative ratios of the components of the mixture are declared, the technical result declared above is not achieved.

For example, a decrease in the total percentage of granular electrocorundum of all these fractions leads to a decrease in the refractory properties of the resulting linings, and its excessive increase to a decrease in the strength of the lining both in raw material and after drying and firing. A decrease in the percentage of silicon carbide over the specified range leads to a decrease in the metal and slag resistance of the resulting linings, and its increase also to a decrease in the strength of the lining both in the raw material and after drying and firing. A decrease in the percentage of high alumina cement as a hydraulic binder and the above varieties of finely dispersed corundum beyond the stated ranges causes a decrease in the strength of the resulting lining in the raw material after drying and firing, and its increase leads to a significant decrease in the deformation temperature under load. The use of plasticizing additives in an amount less than the declared percentage range requires the use of more mixing water, which leads to an increase in the open porosity of the refractory and therefore worsens its metal and slag resistance. The increase in the percentage of plasticizing additives above the declared range still will not allow to further reduce the amount of mixing water and therefore is not advisable. The use of tabular corundum fr. -20 μm, which gives the mixture plasticizing properties, also reduces the amount of mixing water used and therefore leads to a decrease in the open porosity of the refractory, but increasing its percentage above the declared range is impractical, since it does not lead to a noticeable improvement in plasticizing properties, but causes an increase in the cost of refractory concrete mix.

These circumstances indicate a solution to the stated above objectives of the present invention due to the presence of the options of the proposed refractory concrete mixture of the above distinguishing features.

As part of the proposed refractory concrete mixture, silicon carbide fr. 1.6-1.25 mm, for example, silicon carbide No. 125, granular electrocorundum of the above fractions with an alumina content of not less than 99.4 wt.% And an iron oxide of not more than 0.1 wt.%, High alumina cement with an oxide content aluminum in the range of 70-80 wt.%, as well as fine sludge electrocorundum fr. -50 microns and fine electrocorundum fr. <63 μm, obtained, for example, by grinding in a mill with an alumina content of not less than 98 wt.% And iron oxide of not more than 1.5 wt.%.

The applicant made a control sample of the refractory from the refractory concrete mixture selected for the prototype, as well as prototypes No. 1-19 of the proposed refractory concrete mixture and the corresponding experimental samples of refractories No. 1-19 with different numbers. A control sample of the refractory mixture from the prototype mixture and prototypes No. 1-19 of the proposed mixture were made in the form of a cube with a rib size of 60 mm Table 1 shows the compositions of the used prototype mixture and prototypes No. 1-4 of the first embodiment of the proposed refractory concrete mixture for the case when it contains silicon carbide and fine alumina sludge fr. -50 microns. Table 2 shows the compositions of prototypes No. 5-7 of the first embodiment of the proposed refractory concrete mixture for the case when it contains silicon carbide and, as fine-grained corundum, a mixture of electrocorundum sludge fr. -50 microns and tabular corundum fr. -20 microns. Table 3 shows the compositions of prototypes No. 8-13 of the second version of the proposed refractory concrete mixture for the case when it does not contain silicon carbide, and as a fine aluminum oxide contains a mixture of fine sludge electrocorundum FR. -50 microns and tabular corundum fr. -20 microns. Table 4 shows the compositions of prototypes No. 14-19 of the third version of the proposed refractory concrete mixture for the case when it does not contain silicon carbide, and as finely divided alumina contains finely divided electrocorundum fr. <63 μm.

In tables 1-4, the content of mixing water and plasticizing additive is indicated as a percentage of the total mass of the remaining components of the mixture (in excess of 100%), with the exception of the data on the prototype mixture (see table 1), for which the percentage of plasticizing additive, as in the description of the prototype invention, is included in 100% of the mass of the mixture (not in excess of 100%). As a plasticizing additive, sodium tripolyphosphate mixtures No. 3, 5, and 9 were used for prototypes, a mixture of calcined soda and sodium lignosulfonate for experimental mixtures No. 1, 6, and 11 at a ratio of 4: 1, and for experimental mixtures No. 4, 7 , 10 and 12 a mixture of boric acid, citric acid, soda ash and lithium carbonate at a ratio of 2: 3: 1: 0.15, for prototype mixtures No. 2, 8 and 13 a mixture of citric acid, soda ash and lithium oxide the ratio of 3: 1: 0.15, and for the experimental samples of the mixture No. 14-19 organic fiber.

A control sample of the refractory from the prototype mixture was made in accordance with the technology described in the description of the prototype invention.

The manufacturing process of the proposed refractory concrete mixture and the production of refractory lining from it for all variants of the invention and prototypes of refractories is of a similar nature and is as follows.

Initially, all fractions of granular electrocorundum or granular electrocorundum and silicon carbide are mixed in a forced-action concrete mixer or paddle mixer for 1-2 minutes. Then add to the mixer 50% of the required amount of mixing water and mix for another 1.0-1.5 minutes. A mixed and moistened granular electrocorundum or a mixture of granular electrocorundum with silicon carbide is supplied with a complex finely dispersed binder in the form of a mixture of high-alumina cement as a hydraulic binder, plasticizing additive and finely dispersed corundum, i.e., finely dispersed alumina fr. <63 microns, or fine sludge electrocorundum fr. -50 microns, or a mixture of fine sludge electrocorundum fr. -50 microns and tabular corundum fr. -20 microns, after which they are mixed for 1.5-2.0 minutes. Then the remaining part (50%) of the mixing water is added to the mixer and mixed until a homogeneous mass is obtained, usually within 1.5-2.0 minutes.

To obtain a refractory lining, the resulting concrete mass is laid in layers in a mold, formwork or template under the influence of vibration using platform or deep vibrators or vibrators mounted on the walls of the molds, formwork or templates. The formation time of each layer of mass in the form from the moment of application of vibration is, as a rule, 5-6 minutes. The manufacture of refractory lining is carried out at an ambient temperature of from 20 to 25 ° C. After 24 hours, the mold or formwork is disassembled and the obtained refractory samples are incubated for 3 days in wet conditions at a temperature of 18-20 ° C.

Drying and first heating of the lining made of the proposed refractory concrete mixture is carried out as follows. Initially, the lining is heated to a temperature of 105 ° C with a heating rate of not more than 15 ° C per hour, then it is kept at this temperature for at least 24 hours, it is again heated to a temperature of 500 ° C with a heating speed of not more than 30 ° C per hour, maintained at this a temperature of at least 15 hours, after which it is heated to a temperature of 1000 ° C with a heating rate of not more than 50 ° C per hour and maintained at least 15 hours.

Prototypes No. 1-19 of refractories in the form of a cube with a rib size of 60 mm, which were tested to determine their basic physical and mechanical properties, were made as follows. Mixing of the mixture for the manufacture of samples was carried out with drinking water with a temperature of 20-25 ° C. Filling of a detachable steel mold, lubricated from the inside with machine oil, was carried out manually by layer with a spatula when the vibroinstallation was working. Each loaded layer of mass was additionally loaded with a load providing a load of 0.05-0.10 kg / cm ² until moisture appeared on its surface. After pouring, the surface of the sample was carefully leveled with a metal plate. The molded samples were covered with wet cotton in two layers. After exposure for 24 hours, the mold was opened, the obtained sample was mounted on a flat metal plate, covered with a damp cotton cloth in two layers and kept for two days. As the fabric dries, it is further moistened.

During testing, the main physical and mechanical parameters of the control sample of the refractory from the prototype mixture and prototypes No. 1-19 of the refractories from the proposed refractory concrete mixture were determined according to GOST 2409-95 and GOST 4071-94, and tests for slag resistance were carried out according to the method described in of the prototype invention, water was used as a saturating liquid and the load was applied parallel to the laying layers. Obtained during testing, the main physical and mechanical properties of the control sample of refractory material from the prototype mixture and prototypes No. 1-19 of refractories are shown in tables 5-8.

An analysis of the test results (see tables 5-8) of refractory samples showed that the refractories obtained from the variants of the proposed refractory mixture have slag resistance ranging from 1.5-1.9 mm (samples No. 2, 5, 7, 8, 11 and 13 ) up to 2.5-2.8 mm (samples No. 1, 4, 9, 10, 15, 16, 17 and 19), which is significantly better than the slag resistance of the control sample of the refractory from the prototype mixture, which is 3 mm. At the same time, the open porosity of almost all prototype refractory samples was lower than that of the control sample from the prototype mixture, with the exception of prototypes No. 1, 2, and 15, for which the open porosity remained at about the same values as the control sample.

The compressive strength after drying for all prototypes No. 1-19 refractories ranges from 24.1 N / mm ² (for prototype No. 5) to 90 N / mm ² (for prototype No. 8), which is significantly higher ultimate compressive strength after drying a control sample from a prototype mixture of 20 N / mm ² . Moreover, in individual test specimens of refractories, a significant increase in the compressive strength after firing at a temperature of 1600 ° C to values of 100-135 N / mm ² (test samples No. 8, 9 and 15), as well as after firing at a temperature of 1000 ° C, , that is, in the range of softening temperatures, to a value of 72.5 N / mm ² (prototype No. 8) compared with a control sample in which these values are 87 N / mm ² and 65 N / mm ^2, respectively.

Tests for heat resistance in the heating mode to 1300 ° C and subsequent cooling with water showed that the refractory linings obtained on the basis of the proposed refractory concrete mixture withstand 13-17 heat exchanges until the first crack and 38-42 heat exchanges until the lining collapses, while for refractory linings based on a prototype mixture, these indicators have values of 4 and 7 heat exchange, respectively. This indicates a significant increase in the heat resistance of refractories based on the proposed refractory concrete mix.

Thus, the proposed refractory concrete mixture provides refractories with higher slag resistance and ultimate compressive strength after drying.

Claims (16)

1. Refractory concrete mixture containing granular electrocorundum and a complex fine binder based on a mixture of high-alumina cement, fine alumina and plasticizing additive, characterized in that it contains silicon carbide and finely dispersed corundum as fine alumina in the following components, wt.%. : granular electrocorundum fractions 6-3 mm 15-22, fractions 3-1 mm 8-20, fractions 1-0 mm or a mixture of fractions 0.5-0 mm and fractions 1-0.5 mm 13-27, silicon carbide 13 -27, fine corundum 14-24, ysokoglinozemisty cement 7-16, plasticizer 0,03-0,55. 2. The mixture according to claim 1, characterized in that it contains silicon carbide fractions of 1.6-1.25 mm. 3. The mixture according to claim 1, characterized in that it contains a mixture of granular electrocorundum fractions of 0.5-0 mm and fractions of 1-0.5 mm, taken in the ratio (0.8: 1.2) - (1.2 : 0.8). 4. The mixture according to claim 1, characterized in that it contains, as finely divided corundum, an electrocorundum slurry of a fraction of -50 μm in an amount of 14-18 wt.%. 5. The mixture according to claim 1, characterized in that, as a finely dispersed corundum, it contains a mixture of slurry of electrocorundum fraction -50 microns in an amount of 4-6 wt.% And tabular corundum fraction -20 microns in an amount of 16-18 wt.%. 6. The mixture according to claim 1, characterized in that it contains as a plasticizing additive sodium tripolyphosphate in an amount of 0.45-0.55 wt.%. 7. The mixture according to claim 1, characterized in that it contains as a plasticizing additive a mixture of soda ash in an amount of 0.15-0.25 wt.% And sodium lignosulfonate in an amount of 0.045-0.055 wt.%. 8. The mixture according to claim 1, characterized in that it contains as a plasticizing additive a mixture of boric acid in an amount of 0.015-0.025 wt.%, Citric acid in an amount of 0.025-0.035 wt.%, Soda ash in an amount of 0.005-0.015 wt. % and lithium carbonate in an amount of 0.001-0.002 wt.%. 9. The mixture according to claim 1, characterized in that it contains as a plasticizing additive a mixture of citric acid in an amount of 0.025-0.035 wt.%, Soda ash in an amount of 0.005-0.015 wt.% And lithium oxide in an amount of 0.001-0.002 wt. % 10. Refractory concrete mixture containing granular electrocorundum and a complex fine binder based on a mixture of high alumina cement, fine alumina and plasticizing additive, characterized in that it contains as a fine alumina a mixture of fine alumina sludge fraction - 50 microns and tabular 20 microns with the following content of components, wt.%: Granular electrocorundum fraction 3-1 mm 28-42 or a mixture of fractions 6-3 mm in an amount of 17-25 and fractions 3-1 mm in an amount e 27-33, fractions 1-0 mm 18-42, finely divided slurry of electrocorundum fraction -50 microns 5-10, tabular corundum fractions -20 microns 14-17, high alumina cement 6-8, plasticizing additive 0.03-0, 55. 11. The mixture of claim 10, characterized in that it contains as a plasticizing additive sodium tripolyphosphate in an amount of 0.45-0.55 wt.%. 12. The mixture according to claim 10, characterized in that it contains as a plasticizing additive a mixture of soda ash in an amount of 0.15-0.25 wt.% And sodium lignosulfonate in an amount of 0.045-0.055 wt.%. 13. The mixture according to claim 10, characterized in that it contains as a plasticizing additive a mixture of boric acid in an amount of 0.015-0.025 wt.%, Citric acid in an amount of 0.025-0.035 wt.%, Soda ash in an amount of 0.005-0.015 wt. % and lithium carbonate in an amount of 0.001-0.002 wt.%. 14. The mixture according to claim 10, characterized in that it contains as a plasticizing additive a mixture of citric acid in an amount of 0.025-0.035 wt.%, Soda ash in an amount of 0.005-0.015 wt.% And lithium oxide in an amount of 0.001-0.002 wt. % 15. Refractory concrete mixture containing granular electrocorundum and a complex fine binder based on a mixture of high-alumina cement, fine alumina and plasticizing additive, characterized in that it contains finely dispersed alumina fraction <63 μm in the following components, %: granular electrocorundum fraction 3-1 mm 18-40 or a mixture of fractions 6-3 mm in the amount of 18-25 and fractions. 3-1 mm in the amount of 18-32, fractions 1-0.5 mm -9-42, finely divided electrocorundum fractions <63 μm 30-35, highly alumina cement 7-9, plasticizing additive 0.2-0.3. 16. The mixture according to p. 15, characterized in that it contains organic fiber as a plasticizing additive.