SU1335552A1 - Method of producing periclase carbon refractory - Google Patents

Abstract

This invention relates to methods for producing periclase-carbon refractories. The aim of the invention is to increase the durability of the refractory in service by reducing the carbon burnout. The refractory is made by dosing and mixing periclase powder, graphite sang and resin simultaneously in one mixer. The carbon burn rate is 16.9-134.5 mg / cm at winch at 600 ° C for 5 hours „2 tabLo

Description

The invention relates to the fire-retardant industry and can be used in ferrous and non-ferrous metallurgy for the manufacture of linings for thermal units, for example, converters, electric melting furnaces and other

The purpose of the invention is to increase the durability of refractories in the service by reducing the degree of carbon burnout.

A graphite spel is a waste product, produced, for example, by casting iron, due to its cooling and release of carbon dissolved in it, in the form of graphite flakes together with particles of iron and slag. The chemical composition of graphite sang is as follows,%: carbon in graphite form 50 -80, iron and its various oxides up to 30; silicon dioxide 3-5; calcium oxides and impurities of manganese, nickel and chromium 1-5. According to the phase composition, graphite spel is an intergrowth of graphite particles with inclusions of iron, its various oxides, microparticles of slag, represented by an aggregate of glass and minerals of the melilit group.

The mechanism for the formation of periclase-carbon refractories of the proposed composition consists in wetting resin with graphite sang, polymerization cMOHiji at low temperatures and thus forming a strong frame between the grains of periclase powder and graphite sang, With an increase in temperature under the service conditions of the refractory to 520-640 ° The removal of volatile substances from the resin and periclase powder occurs. “Further temperature increase leads to the oxidation of graphite sang with the formation of oxides of carbon and iron. The former form reducing environment that prevents further oxidation of graphite sang, and the latter react with periclase to form high-refractory compounds — magnesiovus titus and magnesiaferrite by the reactions

2C +

2CO + 0

2Re + Og --2FeO;

AFeO + Og -2Fe,

MgO + FeO - MgOFeO

MgO + FejOj- MgO-Fe Oj The reaction of the formation of magnesia and magnesioferrite is accompanied by an increase in volume of about 7%,

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which leads to compaction of the structure of periclase-carbon products, thereby preventing the diffusion of oxygen in them. At high temperatures, there is a reducing medium in the products, the grains of periclase are bound by high refractory magnesian iron compounds that prevent carbon burnout. The preservation of carbon at the service temperature of periclase-carbon refractories per. The compaction of its structure is the basis for increasing its durability in the 5 linings of thermal units, such as converters and electric steel-smelting furnaces.

The advantage of simultaneously mixing all components in one mixer is that the introduction of graphite sang together with coarse-grained and finely ground periclase powder, as well as resin, leads to simultaneous coating of grains of all components and resin particles with graphite spelled. This causes a decrease in the coefficient of internal friction simultaneously. grain, which leads to an increase in plasticity and homogeneity of mass

Periclase-carbon refractories obtained as follows.

All components are metered and simultaneously mixed in one mixer for 5-15 minutes „

The resulting mass is fed to the molding of products using the methods of pressing, tamping or vibration at a temperature not exceeding 120 ° C. They are manufactured without drying or after drying in a reducing environment at 170-300 C (within 1-2 days), shipped by the consumer. Products without drying have sufficient strength and density. Therefore, the feasibility of drying products is determined only by the absence of conditions for coking the linings of thermal units from periclase-carbon refractories. For example, it is impractical to convert periclase-carbon refractories for converters and pouring ladles due to the coking conditions, it is possible to organize their coking in electric steel-smelting furnaces, and for vaults and. walls of open-hearth furnaces, heating plates it is necessary to use periclase-carbon refractories only after they are dried

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As periclase powder, you can use fused periclase, its sub melting (crust) and periclase lime powder, corresponding to GOST. Resins can be used in a different, personal form; coal, petroleum, phenol-formaldehyde, etc.

For the production of control samples according to the proposed method and prepared lazouglerodlyh samples prepared by pressing samples with a height and diameter of 50 mm at a specific pressure of 1 to 25 MBa. The samples are burned at 1600 ° C (5 hours exposure) in air and the degree of burnout is determined as in Example 1 carbon

PRI M Tl p 3. For perikvestnom, sintered periclase powder of fractions 3.0–1.0 mm and less than 0.06 mm, made and used for the production of periclase, periclasechromite and chromite – periclase products, sulfite solution, is used. alcohol stillage (lignosulfonate resin) pl. 1.22 g / cm, flake graphite, coal

By simultaneously mixing the following components, wt.%: sintered periclase powder of a fraction of 3–1 m and less than 0.06 mm 94 graphite opel 3, 15 coal tar 3 in one mixer for 10–15 min. From this mass, samples are pressed with a height and diameter of 50 mm at a specific pressure of 125 ffla. Samples are fired at 1600 ° C (5 hours of the prepared coke-chemical resin — 20 holders) in air and similar to 25

thirty

3

production, corresponding to the specifications, phenol-formaldehyde resin - liquid bakelite, aluminophosphate and graphite spel of a converter shop.

Example 1 (known). The mass for periclase-carbon samples is prepared by successively mixing 60 wt.% Sintered periclase powder with a fraction of 3-1 mm with 3 wt.% Binder (linosulfonate resin and aluminophosphate 1: 1) for 3-5 minutes, add 5 wt.% Graphite Mix for 3-5 minutes, add 32 masd of finely ground periclase powder with fraction less than 0.06 mm. The mass is stirred for 3-5 minutes and from this mass samples are pressed with a height and diameter of 50 mm at a specific pressure of 125 MPa. The samples are burned at 1600 ° C (5 hours of exposure) in air and the degree of carbon burnout is determined by the amount of mass loss before and after burning:

Dt uC / S

where dmc carbon burnout, mg / cm;

DS - carbon mass reduction

after roasting, mg;

S - burnout area, see

Example 2 (control mixture) Mass for periclase-carbon materials: The method for producing periclase-carbon samples is prepared by simultaneously mixing refractory materials by dosing the following components, wt.%: Mixing the periclase powder, sintered periclase powder, components and tions of 3-1 mm and less than 0.06 xm 79j scale graphite 15; coal tar 6, simultaneously in one mixer

but example 1, carbon burnout is determined.

The compositions of the masses and the properties of the samples made from them according to the proposed method and the known technology of testing the samples in examples A-7, similar to example 3) are given in table. one .

As can be seen from table 1, in the products obtained by the proposed method, the degree of carbon burnout is on average 3-8 times less than in the known

The properties of periclase-carbon products obtained by two technologies after 1 day. storage (without drying) are given in table 2.

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Periclase-carbon products made using the technology of simultaneous mixing of components have higher strength, lower porosity and increased apparent density compared to products made using the technology of sequential mixing of components

, of the invention

resin and molding the mixture, about tl and increasing its durability in the service by reducing the degree of burnout, the drainage is 10-15 minutes. From this mass

lazar-carbon samples prepared compacted samples with a height and a diameter of 50 mm at a specific pressure of 1 25 MBa. The samples are calcined at 1600 ° C (5 hours exposure) in air and, in analogy to Example 1, the degree of carbon burnout is determined

Example 3. Mass for pericute by simultaneous mixing of the following components, wt.%: Sintered periclase powder of fraction 3–1 m and less than 0.06 mm 94 graphite opel 3, coal tar 3 in one mixer 10- 15 minutes. From this mass, samples are pressed with a height and diameter of 50 mm at a specific pressure of 125 ffla. The samples are burned at 1600 ° C (5 hours of exposure) in air and the like

but example 1, carbon burnout is determined.

The compositions of the masses and the properties of the samples made from them according to the proposed method and the known technology of testing the samples in examples A-7, similar to example 3) are given in table. one .

As can be seen from table 1, in the products obtained by the proposed method, the degree of carbon burnout is on average 3-8 times less than in the known

The properties of periclase-carbon products obtained by two technologies after 1 day. storage (without drying) are given in table 2.

 A method for the manufacture of periclase-carbonaceous refractories by dosing, mixing periclase powder, gg, graphite-containing component and

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Periclase-carbon products made using the technology of simultaneous mixing of components have higher strength, lower porosity and increased apparent density compared to products made using the technology of sequential mixing of components

, of the invention

 A method of making a periclase coal of a purebred refractory by dosing, mixing a periclase powder, a graphite-containing component and

resin and molding the mixture, about tl and a method for producing a periclase angle of a native refractory by dosing, mixing the periclase powder, the graphite-containing component and

increase its durability in the service by reducing the degree of burnout ug51335552

Lerod ,. as a graphite-containing component, graphite spel is used, and mixing is carried out simultaneously in one mixer with the following content of components, mas%:

Composition

The content of components, wt%

Sintered periclase powder

Famous 1

Proposed 2

3 4 5 6

table 2

Properties Indicators on the technology of mixing components

- - -.- 1 .- “--- in ...“ .- -. - - .. - -

sequential simultaneous

Tensile strength

under compression, MPa 31 ,, 6.39,7

Opened poris-. %,% 7,65,4

Apparently with density, g / cm 2,782.83

VNIIPI Order 4016/21 Circulation 587 Subscription Proizv.-polygr. pr-tie, Uzhgorod, st. Design, And

th

but

70-94

3-20 3-10 blitz 1

comrade, mas „%

Coal tar

The degree of carbon burnout at 1600 ° C (5 h exposure), mg / cm

ycha- gra- 6 1 5

3 6 6 10

Phenolformaldehyde-to-resin 5

448.7

45.2

134.5

16.9

38.2

29.2

Claims (1)

Claim A method of manufacturing a periclase-carbon refractory by dosing, mixing periclase powder, a graphite-containing component and a resin and molding the mixture, characterized in that in order to increase its durability in service by reducing the degree of burnout Leroda ,. as graphite-containing Periclase th component use graphite powder 70-94 spel, and mixing are simultaneously- Graphite but in one mixer at the next spel 3-20 the content of components, wtD: Resin 3-10 Table 1 Composition The content of components, mass The degree of carbon burn at 1600 ° C (5 h exposure), mg / cm ² Sintered Periclase Powder Graphite spell Coal tar Famous 1 79 Flake graphite 1 5 6 448.7 Proposed 2 94 3 3 45,2 3 91 3 6 134.5 4 79 fifteen 6 16.9 5 70 20 10 38,2 6 80 55 Phenol formaldehyde resin 5 29.2 table 2 Properties Component mixing technology indicators consistent simultaneous The limit of compressive strength, MPa 31.6 .39.7 Open porosity. 7.6 5,4 The apparent density, g / cm ^e 2.78 2.83 VNIIIPI Order 4016/21 Circulation 587 Subscription Custom polygr. pr-tie ,, Uzhhorod, st. Project, 4