RU2567911C1 - Composition for manufacturing of fireproof concretes - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: composition for manufacturing of fireproof concretes contains, wt %: spent catalyst IM-2201 10-15, crushed carbonate rocks of fraction 5-10 mm 33-40, H₃PO₄ 10-15, dolomite siftings 10-13, sludge formed as a result of aluminium and its alloys etching with concentrated solutions of caustic soda with content, wt %: SiO₂ - 4.5; Al₂O₃ - 78.5; Fe₂O₃ - 2.9; CaO - 2.5; MgO - 1.1; R₂O - 4.1; ignition loss - 6.4, 24-30.

EFFECT: increased compression strength and heat resistance of fireproof concretes, recycling of industrial wastes.

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Description

The invention relates to the field of building materials, in particular the production of heat-resistant concrete (composites) based on chemical binders. Chemical binders used in heat-resistant concrete include liquid glass, silicate block (a transparent glassy alloy of alkaline silicates - semi-finished liquid glass) and phosphate bonds.

Known compositions for producing porous aggregates (for concrete) based on chemical binders of the following composition, wt.%: Water glass - 45-65; sodium chloride - 5-15; the waste of a mining and processing factory in coal enrichment - 15-20; inter-shale clay formed during the production of oil shale. - 15-20 (Pat. Of the Russian Federation No. 2440312, IPC С04В 14/24. Composition for the production of porous aggregate / Abdrakhimova E.S., Roshchupkina I.Yu., Abdrakhimov V.Z., Kulikov V.A .; the applicant and patent holder Samara State Aerospace University named after academician SP Korolev No. 2010122114, application 05.31.2010; publ. 01.20.2012. bull. No. 2) [1].

The disadvantage of this composition is the relatively low strength of 2.65-2.75 MPa.

Closest to the invention is a composition for producing heat-resistant composites (concrete), comprising the following components, wt.%: Alumina-containing sludge - 10.5-10.53 (220 kg / m ³ ); spent catalyst IM-2201-10.5-10.53 (220 kg / m ³ ); crushed stone - 35.88-35.89 (750 kg / m ³ ); sand - 30.62-30.63 (640 kg / m ³ ); H ₃ PO ₄ - 12.44-12.45 (260 kg / m ³ ) (Khlystov A.I. Increasing the efficiency of heat-resistant composites through the use of chemical binders / A.I. Khlystov, S.V. Sokolova, A.V. Vlasov // Building materials, equipment, technologies of the XXI century. - 2012. - No. 9. - P.38-42) [2].

The disadvantages of this composition are the relatively low tensile strength after compression after hardening and heating to a temperature of 1200 ° C and low heat resistance.

The essence of the invention is improving the quality of heat-resistant concrete.

The technical result of the invention is to increase the compressive strength and heat resistance of heat-resistant concrete.

The specified technical result is achieved by the fact that dolomite seedlings and sludge formed as a result of etching of aluminum and its alloys with concentrated solutions of sodium hydroxide with a content, wt.%, Are additionally introduced into the known composition, including spent catalyst IM-2201, crushed stone and Н ₃ РО ₄ . : SiO ₂ - 4.5; Al ₂ O ₃ - 78.5; Fe ₂ O ₃ - 2.9; CaO - 2.5; MgO - 1.1; R ₂ O - 4.1; p.p.p. - 6.4, in the following ratio of components, wt.%:

spent catalyst IM-2201 10-15 crushed stone from carbonate rocks of a fraction of 5-10 mm 33-40 dolomite seeding 10-13 H ₃ RO ₄ 10-15 aluminum sludge and its alloys with concentrated solutions of caustic soda with a content, wt.%: SiO ₂ - 4,5; Al ₂ O ₃ - 78.5; Fe ₂ O ₃ - 2.9; CaO - 2.5; MgO - 1.1; R ₂ O - 4.1; p.p.p. - 6.4 24-30

Dolomite seeding is a waste of the Sokovsky quarry. The oxide chemical composition of the waste used is presented in table 1, and the element composition in table 2. Studies have shown that due to the low hardness of dolomite grains (CaMg (СО ₃ ) ₂ ), it cannot be used as a fine aggregate for ordinary concrete. Therefore, to obtain heat-resistant composites, a chemical method was adopted for binding dolomite-containing wastes through the use of phosphate coater.

Aluminum and its alloys are most often etched in a solution containing 50-150 g / l sodium hydroxide, heated to 50-70 ° C. The etching time, depending on the state of the surface and the concentration of sodium hydroxide, is 0.5-1.5 minutes. The etching of aluminum and its alloys is associated with a decrease in the initial dimensions of the parts, which should be especially taken into account when processing clad parts and parts with tight tolerances. In the latter case, etching is carried out in solutions with a lower concentration of sodium hydroxide.

The chemical oxide composition of the sludge resulting from the etching of aluminum and its alloys with concentrated solutions of caustic soda is presented in table 1, and the element-wise in table 2.

As a result of etching of aluminum in sodium hydroxide, sodium aluminate is formed and hydrogen is released. Aluminum dissolves in caustic soda with the release of hydrogen and the formation of a composite aluminate, which exists only in an alkaline solution. The reaction taking place in this case can be recorded in two ways:

1.2Al + 2NaOH + 2H ₂ O → 2NaAlO ₂ + 3H ₂ ;

2.2Al + 2OH + 6H ₂ O → 2 (Al (OH) ₄ ) + 3H ₂ .

Intensive hydrogen evolution indicates a rapid dissolution of aluminum and can serve as a signal for unloading parts from the solution.

After alkali regeneration from spent pickling solutions, a precipitate is deposited - an alumina-containing sludge that concentrates on the bottom of the bath and gradually crystallizes. The sludge of this group is characterized by a high content of Al ₂ O ₃ , which contributes to a significant increase in heat resistance when used in compositions of heat-resistant concrete (composites). The increased content in the sludge of alkalis (R ₂ O = 4.1%, table 1) will reduce the firing temperature of heat-resistant concrete and thereby increase the strength of the product at relatively low temperatures, and a high percentage of pp reduce its density of products. A distinctive feature of the sludge from the processing of aluminum and its alloys from other cleaners is its high degree of dispersion. A positive consequence of the high dispersion of the sludge (9000-10000 cm ² / g) is its great plasticity (plasticity number more than 10), which allows it to be used in the manufacture of heat-resistant concrete as a plasticizer.

Aluminochromic waste from the Novokuybyshevsk Petrochemical Plant and sludges resulting from the etching of aluminum and its alloys with concentrated solutions of caustic soda were used as corrective additives.

For the manufacture of heat-resistant concrete, crushed stone was used that meets the requirements of GOST G 8267-93 “Crushed stone and gravel from dense rocks for construction work. Specifications "M600, 800-1000, with an average grain density of 2.0 to 2.5 kg / m ³ from carbonate rocks, mined in the Samara region, fractions of 5-10 mm.

For the manufacture of heat-resistant concrete, phosphoric acid N ₃ PO _{4 was} used as a binder in pure form according to GOST 6552-80, the norm was pure (parts) OKP 26 1213 0021 10. Mass fraction of orthophosphoric acid (H ₃ PO ₄ ) not less than 85% , a density of not less than 1.69 g / cm ³ .

The proposed compositions used the spent catalyst IM-2201 (production waste) that meets the requirements of TU 38.103544-89. The chemical compositions of the catalyst are presented in tables 1 and 2.

According to TU 38.103544-89 spent catalyst IM-2201 must have the following indicators: the appearance of the powder is gray-green in color, bulk density is 1.0-1.5 g / cm ³ ; mass fraction of Al ₂ O ₃ not less than 70%.

Hardening occurs as a result of chemical interaction of phosphoric acid with a filler, especially with a finely ground part thereof, and subsequent polymerization and polycondensation reactions, which intensify as the concrete is dried and heated.

Information confirming the possibility of carrying out the invention The technological process for the production of cementless heat-resistant concrete and the manufacture of products and structures from them includes the preparation of molding materials, molding of products and heat treatment.

It should be noted that for their hardening and a set of brand strength, heat-resistant concrete requires special heat treatment.

For phosphoric acid concrete with the components shown in table 3, heating to 500 ° C with a temperature rise of 200 ° C at a rate of 60 ° C / h and up to 500 ° C - 150 ° C / h, keeping for 4 hours cooling along with the oven.

Table 4 presents the physical and mechanical properties of heat-resistant concrete.

As can be seen from table 4, heat-resistant concrete from the proposed compositions has higher rates of mechanical strength and heat resistance than the prototype.

The resulting technical solution when using dolomite seedlings and sludge formed as a result of etching of aluminum and its alloys with concentrated solutions of caustic soda, improves the mechanical strength and heat resistance of heat-resistant concrete.

The use of technogenic raw materials in obtaining heat-resistant concrete contributes to the utilization of industrial waste, environmental protection, and the expansion of the raw material base for building materials.

INFORMATION SOURCES

1. Pat. Russian Federation No. 2440312, IPC C04B 14/24. Composition for the production of porous aggregate / Abdrakhimova E.S., Roshchupkina I.Yu., Abdrakhimov V.Z., Kulikov V.A .; Applicant and patent holder Samara State Aerospace University named after academician S.P. Queen. No.2010122114. Announced on 05/31/2010; published on January 20, 2012. Bull. No. 2.

2. Khlystov A.I. Improving the efficiency of heat-resistant composites through the use of chemical binders / A.I. Khlystov, S.V. Sokolova, A.V. Vlasov // Building materials, equipment, technologies of the XXI century. 2012. No9. S. 38-42.

Claims (1)

Composition for the manufacture of heat-resistant concrete, including spent catalyst IM-2201, crushed stone from carbonate rocks of a fraction of 5-10 mm and H ₃ PO ₄ , characterized in that it additionally contains dolomite seedlings and sludge resulting from the etching of aluminum and its alloys with concentrated solutions sodium hydroxide content, wt.%: SiO ₂ - 4,5; Al ₂ O ₃ - 78.5; Fe ₂ O ₃ - 2.9; CaO - 2.5; MgO - 1.1; R ₂ O - 4.1; p.p.p. - 6.4, in the following ratio of components, wt.%:
spent catalyst IM-2201 10-15 crushed stone from carbonate rocks of a fraction of 5-10 mm 33-40 dolomite seeding 10-13 H ₃ PO ₄ 10-15 aluminum sludge and its alloys with concentrated solutions of caustic soda with a content, wt.%: SiO ₂ - 4,5; Al ₂ O ₃ - 78.5; Fe ₂ O ₃ - 2.9; CaO - 2.5; MgO - 1.1; R ₂ O - 4.1; p.p.p. - 6.4 24-30