RU2731754C1 - Heat-resistant slag-lintering concrete - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: invention relates to production of construction materials and can be used in making lining of units operating under high temperatures and high cyclicity. Heat-resistant slag-alkaline concrete produced from concrete mixture, containing chamotte of 5–10 mm fraction, chamotte of less than 5 mm fraction, self-breaking ferrochrome slag, sodium hydroxide, portland cement and water, where the mixture additionally contains slag of metal chromium of 5–10 mm fraction, slag of metal chromium of fraction less than 5 mm and metakaolin in following ratio of components, wt%: chamotte of fraction 5–10 mm - 15.0, chamotte of fraction less than 5 mm - 16.0, slag of metal chromium of fraction 5–10 mm - 15.0, slag of metal chromium of fraction less than 5 mm - 15.5, self-breaking ferrochrome slag - 23.5, caustic soda - 2.5, portland cement - 1.0, metakaolin - 0.5, water - 11.0.

EFFECT: technical result is provision of application temperature of more than 1400 °C with preservation of strength characteristics.

1 cl, 3 tbl

Description

The proposal relates to the production of building materials that can be used for the manufacture of linings for heating units, linings for kiln cars of tunnel kilns, and linings operating at high temperatures and increased cyclicity.

Known compositions for the production of heat-resistant slag-alkali concretes containing fireclay filler, finely ground additive (fireclay and fired hydrated alumina cement), ferrochrome slag and liquid glass [RF Patent No. 590291, IPC S04B 19/04 01/30/1978]; fireclay filler with fractions of 5-10 mm and less than 5 mm, self-decaying ferrochrome slag, caustic soda, water [RF Patent No. 2284305, IPC С04В 28/08 27.09.2006].

The disadvantages of the compositions are low mechanical strength, low heat resistance, low application temperature.

Known composition for the production of heat-resistant slag-alkali concretes, containing chamotte fractions of 5-10 mm and less than 5 mm, self-disintegrating ferrochrome slag, caustic soda, refractory fiber, Portland cement, water [RF Patent No. 2437854, IPC C04B 28/08 27.12.2011].

The disadvantage of the composition is the low application temperature.

The closest technical solution is a composition for the production of heat-resistant slag-alkaline concretes containing chamotte fractions of 5-10 mm and less than 5 mm, self-disintegrating ferrochrome slag, caustic soda, refractory fiber, Portland cement, water [RF Patent No. 2437854, IPC C04B 28/08 27.12. 2011].

However, this material was obtained with lower application temperatures (1300-1350 ° C).

The objective of the proposal is to obtain heat-resistant slag-alkali concrete with an application temperature of more than 1400 ° C, while maintaining other strength characteristics at the level.

The technical result is achieved due to the fact that heat-resistant slag-alkaline concrete, obtained from a concrete mixture containing chamotte fraction 5-10 mm, chamotte fraction less than 5 mm, self-decomposing ferrochrome slag, caustic soda, Portland cement and water, in the mixture additionally contains metal chromium slag fraction 5-10 mm, slag of metallic chromium fraction less than 5 mm, metakaolin in the following ratio of components, wt%:

chamotte fraction 5-10 mm - 15.0;

chamotte fraction less than 5 mm - 16.0;

slag of metallic chromium fraction 5-10 mm - 15.0;

slag of metallic chromium of fraction less than 5 mm - 15.5;

self-decaying ferrochromium slag - 23.5;

caustic soda - 2.5;

Portland cement - 1.0;

metakaolin 0.5;

water - 11.

Introduction of metallic chromium slag into the concrete mixture (fused alumina product PPG-75 according to TU 0798-069-001864482-2011, having an average chemical composition, wt%: 75 Al2O3, 10.0 CaO, 1.0 Fe2O3, 8.0 Cr2O3) leads to a change in the phase composition during heating. Slag of metallic chromium is active towards the alkaline component of the slag-alkaline binder. The main compound formed during the interaction of alkali with metal chromium slag is Na, Al (SiO3) 2 * H2O, which leads to an increase in the temperature of 4% deformation under load due to the formation of refractory compounds.

Introduction of metakaolin into the concrete mixture according to TU 5729-097-12615988-2013, having an average chemical composition, wt%: 42.5 Al2O3, 53.5 SiO2, 0.6 Fe2O3, 0.4 TiO2, 0.95 K2O, 0.05 Na2O, 0.15 CaO, allows you to compensate for the decrease in residual compressive strength and heat resistance. Metakaolin is a chemical analogue of chamotte filler, but it is in a finely dispersed and amorphous state. Dispersion of metakaolin is much higher than finely ground chamotte. The introduction of metakaolin allows you to increase the activity of the slag-alkaline binder, without a significant increase in the need for an alkaline grout.

Fireclay grade ZShB, fractions 5-10 mm and less than 5 mm, corresponding to GOST 23037-99 “Refractory aggregates. Specifications ", having an average chemical composition, wt.%: 31.0 Al ₂ O ₃ , 68.0 SiO ₂ , 0.5 Fe ₂ O ₃ , 0.5 CaO + MgO.

Self-decaying ferrochrome slag - whitening according to TU 14-139-201-2012, having an average chemical composition, wt%: 45 CaO, 25 SiO ₂ , 10.0 Al ₂ O ₃ , 8.0 Cr ₂ O ₃ , 10.0 MgO.

Technical caustic soda flaked according to STO 00203312-017-2011, rev. 1.2 with sodium hydroxide content not less than, wt%: 98.5.

Portland cement PC500D0 in accordance with GOST 10178-85.

Table 1 shows the composition of the mixture according to the claimed invention.

Table 2 shows the properties of heat-resistant slag-alkali concrete made according to the composition of Table 1. Water in a dosage of 11% was added to the mixture after thorough mixing in a laboratory forced-action mixer. The samples were molded using vibration compaction. After that, the concrete mixture was heat treated according to the following regime:

- temperature rise to 60-65 ° С within 1.5-2 hours;

- exposure at 60-70 ° C for 4 hours;

- rise in temperature to 90-95 ° C within 1.5-2 hours;

- exposure at 90-95 ° C for 4 hours;

- temperature rise to 110-120 ° С within 2 hours;

- exposure at 110-120 ° C for 7-8 hours;

- temperature decrease to 50-70 ° С within 3 hours.

After passing the heat treatment mode, the molds were disassembled.

Table 3 shows the composition and properties of the prototype.

The density was determined according to GOST 12730.1-78. Compressive strength was determined according to GOST 10180-2012. The flexural strength was determined according to GOST 310.4-81. Heat resistance was determined according to GOST 20910-90. The maximum application temperature was determined as the temperature corresponding to 4% deformation under load according to GOST 20910-90.

According to the data in tables 1-3, it follows that the patented composition, in contrast to the prototype, makes it possible to obtain heat-resistant slag-alkaline concrete with an application temperature of at least 1400 ° C, with the rest of the physical and mechanical characteristics that are not inferior to the prototype. This concrete must be used for the manufacture of linings of heating units, linings of kiln cars of tunnel kilns, and linings operating at high temperatures and increased cyclicity.

These features indicate the achievement of the task.

Table 1 The composition of heat-resistant slag-alkali concrete Components Content in the mixture, wt% Fireclay, fraction 5-10 mm 15.0 Fireclay of fraction less than 5 mm 16.0 Slag of metallic chromium fraction 5-10 mm 15.0 Slag of metallic chromium fraction less than 5 mm 15.5 Self-decaying ferrochromium slag 23.5 Sodium hydroxide 2.5 Portland cement 1.0 Metakaolin 0.5 Water 11.0 TOTAL 100.0

table 2 Properties of heat-resistant slag-alkali concrete Density, kg / m ³ 2150-2300 Compressive strength after hardening, MPa 74.0 Flexural strength after hardening, MPa 9.3 Compressive strength after heating up to 1000 ° С, MPa 57.0 Heat resistance, 800 ° C cycles - water 91 Maximum application temperature 1430

Table 3 Composition and properties of the prototype Material / property 1 2 Fireclay, fraction 5-10 mm 31.0 30.0 Fireclay of fraction less than 5 mm 30.0 28.0 Self-decaying ferrochromium slag 23.5 25.5 Sodium hydroxide 3.0 4.0 Portland cement 1.0 1.5 Refractory fiber 0.5 1.0 Water 11.0 10.0 TOTAL one hundred one hundred Density, kg / m ³ 1950-2100 1950-2100 Compressive strength after hardening, MPa 71.0 85.0 Flexural strength after hardening, MPa 8.5 12.1 Compressive strength after heating up to 1000 ° С, MPa 43.0 58.0 Heat resistance, 800 ° C cycles - water 79 139 Maximum application temperature 1350 1300

Claims (2)

Heat-resistant slag-alkaline concrete obtained from a concrete mixture containing chamotte fraction 5-10 mm, chamotte fraction less than 5 mm, self-disintegrating ferrochrome slag, caustic soda, Portland cement and water, characterized in that the mixture additionally contains metal chromium slag of 5-10 mm fraction, slag of metallic chromium of fraction less than 5 mm, metakaolin in the following ratio of components, wt%: chamotte fraction 5-10 mm 15.0 chamotte fraction less than 5 mm 16.0 slag of metallic chromium fraction 5-10 mm 15.0 slag of metallic chromium fraction less than 5 mm 15.5 self-decaying ferrochromium slag 23.5 sodium hydroxide 2.5 Portland cement 1.0 metakaolin 0.5 water 11.0