RU2325364C1 - Refractory concrete paste for structural unit component lining - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: invention may be used in the ferrous metallurgy, for the manufacture of gasodynamic cutoffs of electric furnaces, burner units, pyrometer units, blocks for lining of working space of soaking pits, industrial ladle lids, and other linings. The refractory concrete paste for the manufacture of linings for structural components of units contains, % weight: aluminous stock-slag, grades 0-14 mm, with Al₂O₃ contents of no less than 70%, 65-73, high-alumina cement 20-30, powdered lignosulphonate plasticiser 0.1-0.2, cyclone corundum dust with particle size of less than 1 mcm up to 0.05, high-alumina waste lining, grades 0-20 mm, with Al₂O₃ contents of no less than 90%, up to 3.

EFFECT: increased resistance of lining of structural components and decreased power consumption due to elimination of product drying.

1 ex, 2 tbl

Description

The invention relates to ferrous metallurgy and can be used for the manufacture of gas-dynamic cut-offs of electric furnaces; burner blocks and pyrometer blocks, blocks for lining the working space of heating wells; lid covers and other linings.

Known refractory mass for the manufacture of burner blocks [1], including, wt.%:

High alumina aggregate (mullite corundum) 55-78 High Alumina Cement 10-30 Water 12-15

The disadvantages of the mass are low strength and heat resistance, high porosity of concrete and, accordingly, low service life (9-17 months) of the burner blocks in the hot-dip galvanizing unit for steel strips. Low strength and heat resistance and high porosity of the known composition are due to the large amount of mixing water and very strong softening during heating. Softening occurs due to the evaporation of water and the destruction of the hydraulic ligament.

The closest in technical essence is the refractory mass [2], including aluminosilicate aggregate, high alumina cement, water and plasticizer alkylaryl sulfonate in the following ratio, wt.%:

Aluminosilicate aggregate  57-80.9 High Alumina Cement  10-30 Alkyl aryl sulfonate  0.1-0.3 Water  9-12.7

The lack of mass is the high water demand, and therefore, the long hardening time of the mass (7 days), insufficient strength, density, high porosity and low temperature of application (up to 1300 ° C).

This mass is taken as a prototype.

The problem to which the invention is directed is to increase the durability of structural elements of linings by increasing the density, mechanical strength, increasing the temperature of the onset of deformation and fire resistance, reducing the cost of their manufacture, expanding the scope, as well as reducing energy costs by eliminating drying of products.

The problem is solved due to the fact that a refractory concrete mass is proposed for the manufacture of linings for structural elements of aggregates, including high-alumina aggregate, high-alumina cement and water, while an alumina intermediate is used as a high-alumina aggregate, for example, slag, fractions 0-14 mm with Al ₂ content O ₃ not less than 70% and high-alumina waste waste lining fraction 0-20 mm with an Al ₂ O ₃ content _of not less than 90%, and technical lignosulfonate as a plasticizer powder and cyclone corundum dust with a particle size of less than 1 μm, with the following components, wt.%:

Alumina semi-finished product (slag)  65-73 High Alumina Cement  20-30 Plasticizer (LST) powder  0.1-0.2 Cyclone Corundum Dust  up to 0.05 High alumina waste  until 3 Water  7-8.

The proposed ratio of components makes it possible to obtain a set of necessary refractory properties at a relatively low cost of weight, since an alumina semi-product (slag) of 0-14 mm fraction is used as the main granular aggregate, instead of mullite and chamotte. The technology for preparing the refractory mass as the rest of the aggregate involves the disposal of the spent lining of monolithic steel ladles and waste from the production of purge units, which are previously milled to a fraction of 0-20. The use of slag with an Al ₂ O ₃ content _of at least 70% and waste with an Al ₂ O ₃ content _of at least 90% as a high-alumina aggregate can increase the density of finished products to 2.85 g / cm ³ and the refractory properties of the concrete mass: fire resistance up to 1800 ° C, the temperature of the onset of deformation under load up to 1550 ° C.

The refractory mass as a plasticizer contains a powdery lignosulfonate, which allows to reduce the water demand of the mass up to 7-8% and to ensure sufficient plasticity of the mass. The upper and lower contents of the components are selected experimentally. When less than 20% cement and less than 0.1% lignosulfonate are introduced into the mass, the mass is not sufficiently plastic. When the lignosulfonate is introduced more than 0.2%, for example 0.4%, the porosity of the products during hardening increases by 10%, due to the evaporation of moisture and, accordingly, the strength decreases. An increase in cement content of more than 30% is impractical due to its high cost.

The use of cyclone dust containing a finely dispersed fraction with a particle size of less than 1 μm (nanoparticles) of the dry corundum mixture can improve the rheological properties of the mass (fluidity, thixotropy) and increase the density.

The presence of the above features allows you to qualify the invention as corresponding to the condition of "novelty." The invention contains a combination of features that reduce energy costs by eliminating drying of products, increasing strength, fire resistance and temperature of use.

The results of the experimental verification of refractory concrete mass for the manufacture of linings of structural elements of units are presented in table 1, which shows the combination of mass components at different quantitative ratios (boundary), as well as the composition of the prototype. The properties of the refractory mass are shown in table 2.

Various compositions of refractory concrete mass for laboratory research were made according to the following technology.

The dosage of the components of the concrete mixture was carried out in the ratio shown in table 1. By the method of vibroforming, cube samples with sizes 100 × 100 × 100 were made and subjected to heat-moisture treatment (TVO) according to the following regime:

preliminary exposure at 15-30 ° C - 2-4 hours heating to 80 ° C - 4 hours, isothermal exposure at 80 ° C - 12 hours, chamber cooling - 2 hours.

After steaming, the cubic samples were redistributed and kept at a temperature of 15-40 ° C in air-dry conditions for at least 48 hours. Next, the density of the cubic samples and the compressive strength were determined. Refractoriness and the temperature of the onset of deformation under load were determined according to current methods. Concrete quality control was performed according to GOST 10180-90 and 12730.4-78.

Example

At the management site for the repair of metallurgical furnaces of ChMK OJSC, the technology of manufacturing the following structural elements of lining from the mass has been mastered and introduced: lid covers, gas-dynamic seals of electrode openings of arches of electric furnaces, burner blocks, and pyrometer blocks of heating wells.

The use of the mass for the manufacture of lining of the covers of the promoted ONRS CCC allowed to abandon the use of expensive imported mass of Feurovib A 47/6, without reducing the resistance. Manufacturing costs decreased by 2 times compared with the imported mass.

The use of pulp for the production of gas-dynamic seals of electrode openings of the arches of electric furnaces in ESPTs No. 2 and No. 6 made it possible to increase the resistance of the sealing rings by 1.5-2 times and bring them closer to the resistance of the arches of electric furnaces, as well as reduce downtime for replacement and repair. The specific consumption of rings per 1 ton of metal at the ESPC-2 furnace decreased by 2 times and amounted to 0.126 kg / t.

The manufacture of burner blocks and pyrometer blocks for heating wells of Rolling Shop No. 3 from the mass made it possible to increase their resistance from 3-4 months to 1 year, which corresponds to the resistance of wells and allowed to reduce repair costs. The specific consumption of refractories per 1 ton of metal decreased by 0.3 kg / t and amounted to 2.03 kg / t.

Information sources

1. The journal "Refractories", 1989, No. 7, S. 40-43.

2. RU 2214984, publ. 10/27/2003.

table 2 Composition number The limit of compressive strength, N / mm ² Density, g / cm ³ Heat resistance, 1300 - water, heat exchange After heat treatment for 4 hours At 110 ° C At 800 ° C At 1350 ° C Prototype 1 27.9 17.5 21.3 - 4-5 Prototype 2 42,4 28,4 32,4 - 5-6 Prototype 3 57.9 41.5 46.2 - 6-7 Compositions: No. 1 55.6 ^x - - 2.75 ^x 15-17 Number 2 67.3 ^x - - 2.85 ^x 20-28 Number 3 41.3 ^x - - 2.83 ^x 20-24 Note. The data, denoted by ^x , were obtained after TBO to 80 ° C and exposure to air.

Claims (1)

Refractory concrete mass for the manufacture of linings for structural elements of aggregates, including high-alumina aggregate, high-alumina cement, plasticizer and water, characterized in that the alumina semi-product is used as a high-alumina aggregate - slag fraction 0-14 mm with an Al ₂ O ₃ content _of at least 70% and high alumina waste spent potlining fraction 0-20 mm with a content of Al ₂ O ₃ is not less than 90%, and as a plasticizer - lignosulfonate technical and powdered corundum cyclone yl having a particle size of less than 1 micron in the following ratio, wt.%: Alumina Intermediate - Slag 65-73 high alumina cement 20-30 technical lignosulfonate powder 0.1-0.2 cyclone corundum dust up to 0.05 waste lining until 3 water 7-8