RU2327672C2 - Composition for production of heat-insulating material - Google Patents

Abstract

FIELD: production of construction materials.

SUBSTANCE: composition for the production of a heat-insulating material includes, % weight: high-modulus liquid glass 20-45, clay raw material 20-60, reinforcement additive 1-3, foaming agent 1-5, water, and, additionally, at least one oxide of a group II-IV metal 0.5-30. As the clay raw material, clay from the group of Afoninskoye, Bogorodskoye, Mordovskoye, Berlinskoye, and Vesselovskoye deposits and the "ПГСОЛ" clay (GOST 2542-81) is used, and a composition containing the following components (% weight) is used as the foaming agent: aluminium powder (active or passivated powder) 10-20; carboxymethyl cellulose 0.01-0.4; barium oxide 0-0.1; chromium potassium alum 0.02-0.03; water 80-90.

EFFECT: increased strength during compression of resulting heat-insulating products, expansion of operating temperature range.

2 cl, 3 tbl

Description

Technical field

The invention relates to the field of industrial products and can be used to produce synthetic foam ceramics - a highly effective means for thermal insulation of pipelines for various purposes, technological equipment, domestic and technical structures, as well as in the form of shaped products or formed directly on a heat-insulated surface by pouring or spreading.

State of the art

The developed method solves the same problem - the creation of highly efficient thermal insulation operating in the field of high and low temperatures, as well as known technical solutions [1-3].

A known method of manufacturing a sound-absorbing material [SU No. 1216170, C1 11/24/1983], which includes the following components, in wt.%:

Soluble glass 10-12 Mineral fiber 34-68 Clay component 10-30 Polyvinyl acetate 10-20 Calcium chloride 1-2 Boric acid 1-2

The disadvantage of this method is the use of expensive compounds in the composition of ceramics, such as polyvinyl acetate, which leads to an increase in the cost of the final product and makes its production economically disadvantageous.

A known method of manufacturing a heat-insulating material [RU No. 2026844, C1 05/10/1992], having the following composition, in wt.%:

Liquid glass 48-53 Silicon 15-23 Alumina hydrate 8-10 Sodium Oxide Hydrate 3-4 Kaolin 17-19

This composition has adhesive properties and qualities of a binder for heat-insulating and dielectric materials with high mechanical properties in normal, low and high temperatures.

The disadvantages of this method are the high cost of the starting components, such as silicon, alumina hydrate and sodium hydroxide, which in this composition are 30%; limited availability of kaolin, the import of which to other areas is economically disadvantageous.

In addition, the lack of mechanical compressive strength and the limitation of the upper value of the operating temperature to 1200 ° C limit the possibilities of using this method in the manufacture of heat-insulating material.

As a prototype of the selected method [RU No. 2091348, C1 09/14/1995], which contains a greater number of features common with the claimed method than the above.

This method is characterized by the fact that to create a heat-insulating material based on cheap and affordable raw materials, the following composition was used, including liquid glass, clay raw materials and a foaming agent, fiberglass (or related material), carboxymethyl cellulose and water with the following components, in wt.%:

Liquid glass 18-30 Clay raw materials 47-57 Foaming agent 1-3 Fiberglass 4-9 Carboxymethyl cellulose 1-4.5 Water 9-19.5

As clay raw materials, clay of the type of red ferruginous montmorillonite composition M _x Si _{8 x} Al ₄ O ₂₀ (OH) ₄ × nH ₂ O, where M is a metal from the series Fe, Al, Mg, Ca, Na and others, more often, was used. only 1 <x <4.

As a foaming agent in this technical solution, aluminum powder was used.

This composition gives the ceramic compressive strength of 2.5-3 MPa and the range of operation of the heat-insulating material up to 1500 ° C using environmentally friendly raw materials.

This method has the following disadvantages. The use of aluminum powder grade PAP-1 (GOST 5494-71), produced by industry, as a foaming agent in the production of synthetic foam ceramics leads to the fact that foaming occurs too quickly, after 2-3 minutes, and it is difficult to lay out the mass in molds if the production goes on a large scale. Therefore, in production, there is an acute problem of reducing the activity of industrial aluminum powder in order to increase the start time of foaming of the mass.

Another disadvantage of this method is the high volatility of powdered aluminum, which creates environmental problems in the workplace: dustiness of rooms and allergic reactions in people working with it.

Another disadvantage of this method is the low mechanical strength of the resulting ceramic foam and high moisture saturation.

SUMMARY OF THE INVENTION

The present invention is aimed at obtaining the following technical result:

- to control the strength, density, porosity, moisture saturation and thermal resistance, depending on the assigned technological task, a variety of clay raw materials are used - clays of the Afoninsky, Bogorodsky, Mordovian, Berlin and Veselovsky deposits and PGSOA clay, differing in the ratio of SiO ₂ / Al ₂ O ₃ ;

- to control the start time of foaming of the ceramic mass, the foaming agent is introduced in the form of aluminum-containing compositions (ASA) of the following composition, in wt.%: aluminum powder (active or passivated powder) - 10-20; carboxymethyl cellulose 0.01-0.4; barium oxide 0-0.1; KCr (SO ₄ ) ₂ · 12H ₂ O 0.02-0.03; water 80-90. The use of ASA allows you to increase the start time of foaming to 20 minutes and at the same time completely eliminate the dustiness of the premises.

In addition, the method has the following advantages - to increase the strength and heat resistance of the samples, the metal oxides of groups II-IV and their compositions are introduced into the ceramic composition.

In addition, the method is characterized in that in order to reduce the cost of the final product, reduce the density and improve the insulating properties, fiberglass, mineral wool, fibrous and powdery asbestos, corundum wool are used as reinforcing additives.

In accordance with the invention, new features are introduced into the method, including the manufacture of a heat-insulating material, namely:

- to increase strength and heat resistance, the range of clay raw materials is expanded, and metal oxides of groups II-IV of the group and their compositions are introduced into the ceramic composition;

- to control the start time of foaming and eliminate dust in the production of ceramics, the foaming agent is introduced in the form of aluminum-containing compositions;

- to reduce the cost of the final product, reduce density and improve insulating properties, fiberglass, mineral wool, asbestos, corundum wool were used as reinforcing additives.

The invention is based on new theoretical and experimental studies on the influence of various factors on the foaming parameters in the production of heat-insulating materials [LC. 2003.V. 73. Issue 5. S.729; Bulletin of UNN. N. Novgorod. 1999, Issue 2. P.86], as well as studies on methods for reducing the activity of aluminum powder and methods for creating stable aluminum-containing compositions.

The choice of the optimal ratios of the components of the composition of high-modulus liquid glass, clay raw materials, reinforcing additives, foaming agent, metal oxides of groups II-IV and water can increase the compressive strength to 3.1-4.5 MPa and expand the operating range of the resulting heat-insulating material to 1600 ÷ 1800 ° C using environmentally friendly raw materials.

The composition is prepared as follows. Dispensed clay raw materials of a certain composition are fed into a ball mill, where it is crushed and ground to a dispersion of 0.2-0.3 mm. Then, a metered reinforcing material is added to the ball mill.

The mass is mixed in order to obtain a dry mixture with a uniform distribution of all components. The dry mixture after the ball mill is fed to a concrete mixer, to which dosed liquid glass with a module 2.1-2.6, a certain amount of metal oxides of groups II-IV and water are added. The mixture is stirred until a homogeneous plastic mass. To the resulting mass add a metered amount of blowing agent in the form of aluminum-containing compositions with a certain activity, which allows you to adjust the start time of foaming. The mixture is mixed until a homogeneous plastic mass is obtained, which is then applied to the surface of the structure or filled into the structure.

The formation of foam ceramics and its curing occurs in two stages. The first stage is foaming (4-100 min) and the subsequent curing of the mass for 10-120 min, the second is the increase in the mechanical strength of the material to a maximum value for 1-2 days at room temperature.

Table 1 shows the dependence of the foaming parameters of ceramics and its properties on the composition of the foaming agent, in Tables 2, 3, the dependence of the properties of ceramics on the composition of clays and additives of metal oxides of groups II-IV

Table 1
The dependence of the foaming parameters of ceramics and its properties on the composition of the foaming agent (ceramic composition, wt.%: High-modulus liquid glass (M = 2.6) - 42, clay raw materials - 23, foaming agent - 1, fiberglass - 2, water - 33) No. Foaming agent The processing time of Al at 200 ° C, min Storage time, day Start time of the mass rise, min Steam release time, min ρ, kg / m ³ The limit of compressive strength, MPa one Aluminum powder prototype (without processing) without limitation 3 four 600 2.0 2 ASA ^a) 0 1-12 2.5 6.3-7.6 310 3.4 3 fifteen 1-12 6.5-8.0 21-40 460 3.5 four thirty 1-12 11-20 78-105 520 3.4 a) ASA - aluminum-containing composition, in wt.%: aluminum 10-20; carboxymethyl cellulose 0.01-0.4: potassium chromium alum 0.02-0.03; water 80-90.

table 2
The dependence of the properties of ceramics on the composition of clays (reinforcing additive - glass fiber 3%, high-modulus liquid glass (M = 2.6) - 42%, foaming agent - 3%) Clay wt.% in the composition of ceramics ρ, kg / m ³ The limit of compressive strength, MPa Water absorption by volume% (over 10 days) Operating temperature range, ° С Porosity,% Coefficient: thermal conductivity, W / m ° C Myzinskaya (prototype) 47 600 2.0 8-10 1500 72 0.14 Athos 7 190 3.1 4.5 1550 92 0.08 13 300 3.3 4.0 1600 84 0.09 21 430 3.4 3.4 1600 88 0.10 21 430 3.4 3.5 1600 87 0.10 21 ^a) 420 3.4 3.6 1600 86 0.10 21 ^b) 425 3.3 3.5 1600 85 0.10 33 600 3.6 8.7 1600 81 0.11 Mordovian 7 250 3.2 4.5 1550 87 0.08 13 350 3.6 5.0 1600 84 0.10 21 420 3.8 7.3 1600 81 0.11 Bogorodskaya 21 460 4.2 9.7 1650 78 0.12 Berlin 21 470 4.0 4.5 1750 80 0.12 PSGOA 21 380 3.9 4.5 1650 85 0.12 Veselovskaya 21 400 4.0 5.0 1750 83 0.12 Reinforcing additive: a) corundum wool - 3%, b) asbestos - 3%, c) mineral wool - 3%.

Table 3
Dependence of the properties of ceramics on the addition of metal oxides of groups II-IV (Afoninskaya clay - 21% in the composition of ceramics, foaming agent - 3%, fiberglass - 3%, high-modulus liquid glass (M = 2.6) -42%) Oxides wt.% in the composition ρ, kg / m ³ The limit of compressive strength, MPa Water absorption by volume% (over 10 days) Operating temperature range, ° С Porosity,% Wow 0.25-3 440 4.5 5.0 1600 80 ZrO ₂ 0.5-5
10-21
thirty 370-400
420
600 3.5
4.5
4.5 6.2
7.0
7.0 1750
1800
1800 72-85
80
73 CaO 1-5 410-430 3.1 5.3 1500 82 BaO-ZrO ₂ 1-1 420 4.4 5.3 1600 78 KMTS-VaO 1-2 430 4.5 6.0 1600 83 Zno 2-5 350-400 4.3 7.1 1650 85 CaO-CMC 1-1 430 3.4 5.7 1600 85 MgO 2-3 350 3.1 6.0 1600 83 Al ₂ O ₃ 3-5
thirty 400
420 3.3
3.5 5.8
5.8 1600
1650 79
76

Claims (2)

1. The composition for the manufacture of heat-insulating material, including high-modulus liquid glass, clay raw materials, reinforcing additive, foaming agent and water, characterized in that it additionally contains at least one metal oxide of group II-IV, clay is used as a clay raw material, selected from the group: Afoninsky, Bogorodsky, Mordovian, Berlin and Veselovsky deposits and clay PGSOA (GOST 2542-81), and as a foaming agent - a composition containing, wt.%: aluminum powder (active or passivated according to to powder) 10-20; carboxymethyl cellulose 0.01-0.4; barium oxide 0-0.1; chromium potassium alum 0.02-0.03; water 80-90 in the following ratio of components in the composition, wt.%: high modulus liquid glass 20-45 clay raw materials 20-60 reinforcing additives 1-3 foaming agent 1-5 metal oxides of groups II-IV 0.5-30 water 5-30 2. The composition according to claim 1, characterized in that fiberglass, mineral wool, asbestos (fiber and powder) or corundum wool are used as the reinforcing additive.