SU1616881A1 - Refractory gunited composition - Google Patents

Abstract

The invention relates to the refractory industry, mainly to refractory ramming masses. The aim of the invention is to reduce the rebound during gunning, to prevent flaking during heating to 1300-1500 ° C while reducing thermal conductivity. To prepare the refractory mass, the dry components of the mixture are thoroughly mixed. The humidification of the mixture obtained is carried out in a spray nozzle of a gunning installation. The mass rebound during shotcrete is 16.5–18.0%, thermal conductivity at 1200 ° C is 0.62–0.78 W / m ^. K, no exfoliation is observed. 2 tab.

Description

FIELD OF THE INVENTION The invention relates to refractory industry, preferably refractory ramming masses.

The aim of the invention is to reduce the rebound during gunning, to prevent delamination during heating to 1300-1500 0 while reducing thermal conductivity.

For the refractory gunning mass, the starting components of the mixture: periclase powder (passage through the net 2 100%, residue on the mesh No. 1.5 12%, passage through the mesh 0083 25%), high-alumina cement (talum) and wood Myicy brand 180 carefully mix dry and load into a guncrete unit. Moistening of the mixture is done in the spray nozzle of the unit.

Examples of compositions of refractory toric and cret masses are given in table. 1. In, table, 2 - properties of refractory-mass.

The introduction of the proposed amount of a refractory magnesial-containing aggregate periclase (Example I) or periclazochromite (3) or chromitopericlase (Example 4) into the gunning mass provides the required refractoriness of the lining. It is possible to use friend their refractory aggregates. With the introduction of the composition of the mass of less than 75% refractory filler coating does not have sufficient refractoriness. When the content in the mass of more than 94% of the refractory filler, the heat insulating properties of the lining deteriorate due to an increase in thermal conductivity, and also decrease

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adhesion of gunning coatings at high temperatures, which negatively affects the conditions of steel casting,

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determined by the content of the fraction of 0.08 mm 25-40 wt.%, provides high adhesion of the coating, minimal mass rebound during gunning, reduces the material consumption and shortens the coating time (examples 1-4), reducing the fines content (example 5) an increase in rebound when coating is applied due to deteriorated packing decreases the density of the coating, which leads to the penetration of molten metal and heading into the coating. Excess of content: the fine fraction leads to the formation of a loose coating, as air is captured during application and airborne packing of particles in the coating is not achieved, which leads to flaking and shedding of the coating during drying (Example 6). : The binding-injected into the gunning mass; it ensures adhesion to the surface of the mixed; mixed; in the gunning nozzle with a bond. The following materials can be used as a binder: aluminous cements I (example 3) or high aluminous I (example O phosphate binder (priM jep 4) J liquid glass (example 2) and | other, in the case of using cements they enter dry matter and: moistened with water in the spray gun nozzle Hydraulic binders in the spray guns claimed are preferred,

With the introduction of a binder in an amount of less than 5% of the gunning mass, when applied, it bounces off the lining surface of the shotcrete unit and it is not possible to get a coating of sufficient thickness (Example 9). which interferes with the process of applying the sprayed coating and also reduces the refractoriness of the working layer of the gunned lining (Example 7),

The incorporation into the gunning mass of wood flour due to the formation of a uniform, finely porous structure of the coating after burnout provides the thermal insulation properties of guncrete,

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the coating, as well as compensating for i-volume changes during heating, helps prevent the shotcrete coating from peeling when it is heated to 1400-500 ° C. The dispersion requirement is essential, the burn-out component is particles no larger than 0.20 mm, since using more coarse organic additives, such as sawdust (residue on mesh No. 02 is more than 40%), a coating with large pores is obtained, which leads to the penetration of metal and slag into the coating makes it difficult to clean the tundish after operation (Example 8). The fine dispersion of the organic additive helps to reduce the rebound during shotcrete due to an increase in the specific surface of the mass and uniform distribution particles, resulting in increased adhesion of the applied coating. With the introduction of less than 1 wt.% Wood flour into the composition of the gunning mass, there is no compensation for the volume changes of the gunning layer in the temperature range of 1300-1500 ° C, which causes the coating to fall at these temperatures (Example 10). The introduction of a burnable additive-plus over 1 5% leads to a decrease in mechanical strength-. cover and wear it in contact with the section; molded metal, the impregnation of the coating metal (example 11).

As follows from the table. 2, refractory gunning mass is characterized by the following properties: thermal conductivity at 1200 ° C - 0.62-0.78 W / m K, rebound - 16.5-18 wt.%, Exfoliation of the coating when heated to 1300-1400 Siv service is absent .

Claims (1)

Invention Formula Refractory gunning mass, including a magnesian aggregate, a binder and a finely ground additive, due to the fact that, in order to reduce rebound during gunning, prevent flaking during heating to 1300-1,500 s while reducing heat conductive; THj contains magnesia aggregate fraction 1.5-0.5 mm and less than 0.08 mm, and as a fine-milled additive - wood flour fraction less than 0.2 mm in the following ratio, wt.%: Magnesian aggregate fraction 0.08 mm 25-40 Magnesium aggregate fraction 1.5-0.5 mm Basis Wood flour fraction 0.2 mm.1-5 Binder 5-20 Table I .one t Components Content in gunning mass,% of the proposed :: 1 :: 1 11Т.п 11-1Г.1П111: 1-.1 ivev stnoy 66 46.5 54 40  ... 25 33 40 25 2 and 12.5 5 20 eight 1 15 Indicators Gunny mass Offered PT31111I-1 - PL31113P1 - 0.63 16.5 - Without Remark 0.65 0.78 17.0 18.0 0.62 17.0 0.75 - 37.0 Waz za-15vz za-Ez za-Vol-Otela-sword-sword and th ivev stnoy 69 49 48 52 54 58.4 A8, 23 42 27 3538 33 25, 71 7722 10381029 5 0.6 17Teb Offered -1 - P 0.75 - 37.0 0, 81 0.62 1.18 0.60 1.20 18.5 32.5 25.0 35.2 Pokry- Vysoko-decadiating tne about-ka on-warming. Osci-ovka when warming up