RU2835352C1 - Fractional insulation from foamed glass with closed porous structure and method for production thereof - Google Patents

Abstract

FIELD: performing operations.

SUBSTANCE: invention relates to production of fractional insulation from foamed glass with closed pore system, which can be used in construction and road industry. Mixture for making fractional insulation from foamed glass includes scrap glass, glycerine as a foaming agent, as well as silicate glass with a silicate modulus of M=3.27, with the following ratio of components, wt.%: glycerine 0.5-5.0, silicate glass Na₂O(SiO₂)n 7-9, glass-forming component – scrap glass of different fractions from 0.2 to 120 mcm – the rest. Components are mixed at temperature of 40-60 °C, heated in furnace to temperature of 600 °C, after which glass is softened, and with further increase in temperature – successive sintering, pore formation in the temperature range from 660 to 780 °C and foaming at temperature up to 950 °C. After solidification of the foamed melt in the temperature range from 950 to 750 °C is subjected to sharp cooling in the temperature range from 750 to 30 °C with flowing air at room temperature to undergo a natural crushing process to obtain the finished material.

EFFECT: reduced bulk density and improved heat-insulating properties of fractionated foamed glass with simultaneous increase in strength of granules.

2 cl, 1 tbl, 3 ex

Description

The invention relates to building materials and can be used in the construction and road industry as a lightweight heat-insulating material and at the same time possessing a high ability to withstand loads with different density, different specified fractional component, strength and thermal properties. The proposed fractional insulation is used for the insulation of flat exploited and non-exploited roofs, as well as for the frost-protective layer of road pavements.

A batch for the production of foam glass is known (see patent N292909, dated 15.01.1971), which allows the production of foam glass with closed pores, having in its composition, wt. %:

Sodium hydroxide hydrate - 6-8.5,

Perlite (volcanic glass) - 91.5-94.0.

However, the known composition has a relatively high foaming temperature of 850-950°C, a long firing period (15-60 min) and low heat resistance of 300°C. According to the known composition, the density of foam glass reaches 0.9 g/cm3, which is undesirable for heat-insulating material.

A batch for producing foam glass is known (see patent N393227, dated 05.08.1973), which involves melting glass with the addition of Al2O3, the carrier of which is nepheline concentrate, grinding the glass in a ball mill, mixing with a blowing agent and subsequent heat treatment in a tunnel furnace using the powder method.

The composition of the batch in this case, wt. %:

SiO2 - 68-71,

CaO+MgO - 5-9,

R2O - 14.5-15.0,

Fe2O3 - up to 5,

SO3 - 0.2-0.4,

and besides

Al2O3 - 3-10.

However, in the known method, glass is melted in a bath furnace at a maximum temperature of 1450°C, then crushed in a ball mill, mixed with a blowing agent, and foam glass is obtained in a tunnel furnace at temperatures above 800°C.

Similar in technical essence and chemical composition to the batch used is the composition for producing foam glass by glass melting (see A.S. N806627, C03C 11/00, BI N 7, 1981) with the following ratio of components, wt. %: SiO2 72; Al2O3+Fe2O3 up to 1.2; CaO 6; MgO 0.4; Na2O 16.5; SO3 0.3.

However, in the known preparation of the composition, as in the previous one, there is high-temperature glass melting with subsequent foaming using powder technology. Nepheline concentrate from 5 to 15 wt. % is introduced, unlike in the previous preparation of the composition, not at the stage of melting the main glass, but at the stage of grinding before foaming. The compositions are characterized by the energy intensity of the process and the complexity of the technology.

The closest solution is a method for producing fractional insulation from foamed glass for road construction in the form of a batch, see Russian patent No. 2681157, obtained by mixing a foaming agent in an amount of 0.5...5.0 wt. %, a Na2O(Si02)n modifier with a silicate modulus of 3.2 in an amount of 0.1-6% wt. % and a glass-forming component - the rest at a temperature of 40-60 ° C, heating the mixture in a furnace to a temperature of 600-660 ° C until sintering and softening of the glass particles, pore formation in the temperature range of 660-780 ° C, foaming the mixture in the temperature range of 780-950 ° C, hardening at a temperature of 950-750 ° C followed by rapid cooling from a temperature of 750 ° C to 30 ° C.

The technical result is a decrease in bulk density and an increase in the thermal insulation properties of fractional insulation with a closed cell. An increase in thermal insulation properties and a decrease in bulk density are achieved by variability in the production of fractional foam glass, by changing the grinding value, the time mode of foam glass production, and also by increasing the pore size. Increased strength is achieved due to the thickness of the pore wall.

The technical result is achieved by changing the qualitative composition of the charge, as well as by changing the time interval of the charge being in the sintering zone, depending on the type of material that is planned to be obtained.

Thus, fractional insulation made of foamed glass with a closed porous structure includes broken glass and glycerin as a foaming agent, as well as an additional component - silicate glass, with the following ratio of components, wt. %:

- glycerin in the amount of 0.5-5.0,

- silicate glass Na2O(SiO2)n with a silicate modulus M=3.27 in the amount of 1-9,

- broken glass of different fractions from 0.2 microns to 120 microns - the rest.

Traditionally, glass waste is reduced to the state of flour by finely ground silicate glass (particles 2 - 10 μm). The proposed method allows to reduce the requirement for the fractional composition of grinding (120 μm), thereby reducing energy costs for the preparation of the glass-forming component and improving the ability to set the necessary technical parameters. The composition of the glass-forming component has different fractions from 0.2 μm to 120 μm - this unique ratio of particles of different sizes makes it possible to obtain finished products with the required characteristics in terms of thermal conductivity and strength.

Low water absorption, high strength characteristics, made from raw material batch with additional introduction of a modifier, is based on the features of the physical and physicochemical processes occurring during grinding and heating of the batch, as well as in the displacement and increase of the sintering zone compared to the traditional method of manufacturing foam glass crushed stone.

The method for producing fractional insulation from foamed glass with a closed porous structure includes mixing a glass-forming component, a foaming agent and a modifier. In this case, glycerin is used as a foaming agent, and (Na2O(SiO2)n) is used as a modifier, with the following ratio of components, wt. %:

- glycerin 0.5-5.0,

- silicate glass (Na20(SiO2)n) (with a given silicate modulus of 3.27) - 1-9,

- broken glass - the rest. In this case, broken glass includes different fractions of the glass-forming component from 0.2 µm to 120 µm.

The method is as follows:

- heating the mixture in a furnace to a temperature of 600-620°C until the glass particles soften,

- sintering the mixture for 26-30 minutes with a smooth increase in temperature from 620 to 660°C,

- pore formation in the temperature range from 660 to 780°C,

- foaming in the temperature range from 780 to 950°C,

- glazing solidification of foamed melt, in the temperature range from 950 to 750°C,

- cooling in the temperature range from 750 to 30°C at the exit from the furnace and formation of the final product.

An example of obtaining foam glass according to Russian patent 2681157

A well-known method (obtaining foam glass material with a closed porous structure of bulk density of 190-240 kg/m3).

1. The stage of mixing the foaming component, additional components, and broken glass flour - 5% foaming component.

2. The foaming agent, usually a carbonaceous substance (carbon black, coal, or food grade glycerin), is typically present in an amount of from 1 to about 5 weight percent. The mixed and pressed substance is poured onto a belt into rows of powder mixture, in a mound of mixture typically having a natural angle of repose of about 15 to 50 degrees.

3. After mixing, the material on the belt enters the furnace, where the material is sintered at a temperature range of 620-660°C. When the batch is heated, the glass particles first soften (600…620°C), then the particles sinter - the formation of glass mass and the formation of additional contact surfaces. The sintering time with this method is 21-22 minutes, depending on the type of equipment.

4. Next, the process of pore formation occurs, followed by foaming of the mixture in the temperature range of 660-950°C, until a soft foamed substance is obtained.

After the temperature of the mixture reaches 780°C, the glass mixture will be softened so much that it allows the released carbon dioxide to pass through itself. The volume of the substance expands. The release of carbon dioxide through the glass mass is primarily responsible for the formation of cells and pores in it. Foaming is carried out for a period of time at the maximum foaming temperature, for example, from about 780 to 950°C.

5. Then the melt solidifies at a temperature of 950-750°C.

6. The cooling stage begins at a temperature of 750°C

7. Immediately after this (immediately) the substance is rapidly cooled with flowing air at normal (room) temperature until the final finished material is obtained.

The glass is foamed to a high density and porous structure, the furnace temperature is rapidly reduced to a temperature at which foaming stops, then cooled rapidly with air until the glass experiences "thermal shock" so that the natural crushing process can occur.

After natural decay, irregularly shaped stones with a closed air- and water-impermeable porous structure are obtained.

The bulk density is from 190 to 250 kg/ ^m3 . The average pore size is 0.08-0.1 mm. Thermal conductivity of the working layer, as a rule, at the declared density is, as a rule, 0.085-0.095 W/(m⋅°C).

Examples of obtaining foam glass with a given bulk density and thermal insulation properties described by this invention:

Example 1. Obtaining fractionated foam glass material with a closed porous structure with a given bulk density of 80-110 kg/m3 and thermal conductivity of the working layer (compacted) of 0.06 -0.065 W/(m⋅°C).

1. The stage of mixing the foaming component, additional components, and glass cullet flour (The proposed method allows the use of grinding with a fractional composition from 0.2 μm to 120 μm. This unique ratio of particles of different sizes makes it possible to obtain finished products with the required characteristics. Larger glass particles provide strength, since they form walls of greater thickness, which allows achieving a larger cell without deteriorating the strength characteristics).

- 5% foaming component (glycerin);

- silicate glass (Na2O(SiO2)n) with a given silicate modulus M=3.27 - 7%.

Temperature control during mixing. The temperature range should be between 40-60°C.

2. After mixing, the material on the belt enters the furnace where it is heated to 620°C, then the material is sintered at a temperature range of 620-660°C. When heating the batch, the glass particles first soften (600…620°C), then the particles sinter - the formation of glass mass and the formation of additional contact surfaces. At this stage, the temperature of the mixture in the sintering zone smoothly increases from 620 to 660°C over 30 minutes. As a result, the mixture becomes less dense and has a larger pore than in the known method (approximately 0.7 mm), which will ultimately allow achieving a larger volume of closed gas/air in a unit of foam glass than in the known method.

3. Next, the process of pore formation of the mixture occurs in the temperature range of 660-780 degrees C.

4. At a temperature of 720-765°C, the modifier (Na2O(SiO2)n) in the batch melt forms solid particles.

5. Next, the process of foaming the mixture occurs in the temperature range of 780-950°C, until a soft foamed substance is obtained.

After the temperature of the mixture reaches 780°C, the glass mixture will be softened so much that it allows the released carbon dioxide to pass through itself. The volume of the substance expands. The release of carbon dioxide through the glass mass is primarily responsible for the formation of cells and pores in it. Foaming is carried out for a period of time at the maximum foaming temperature, for example, from about 780 to 950°C.

6. Next, the melt solidifies at a temperature of 950-750°C.

7. The cooling stage begins at a temperature of 750°C.

8. Immediately after this (immediately) the substance is rapidly cooled with flowing air at normal (room) temperature until the final finished material is obtained.

The glass is foamed to the required density and higher pore structure, the furnace temperature is quickly reduced to a temperature at which foaming stops. Then, using air, it is rapidly cooled until the glass experiences a "thermal shock" so that the natural crushing process occurs.

After natural disintegration (crushing), lighter stones of irregular shape with a closed air- and water-impermeable porous structure are obtained. The bulk density is 80-110 kg/m3, the thermal conductivity of the working layer (compacted) is 0.06-0.065 W/(m⋅°C).

Example 2. Obtaining fractionated foam glass material with a closed porous structure with a given bulk density of 120-130 kg/m3 and thermal conductivity of the working layer (compacted) of 0.072-0.075 W/(m⋅°C).

1. The stage of mixing the foaming component, additional components, and glass cullet flour (The proposed method allows the use of grinding with a fractional composition from 0.2 μm to 120 μm. This unique ratio of particles of different sizes makes it possible to obtain finished products with the required characteristics. Larger glass particles provide strength, since they form walls of greater thickness, which allows achieving a larger cell without deteriorating the strength characteristics).

2. - 5% foaming component (glycerin);

- silicate glass (Na2O(SiO2)n) (with a given silicate modulus M=3.27) - 7%.

Temperature control during mixing. The temperature range should be between 40-60°C.

3. After mixing, the material on the belt enters the furnace, where it is sintered at a temperature range of 620-660°C. When the batch is heated, the glass particles first soften (600…620°C), then the particles sinter - the glass mass is formed and additional contact surfaces are formed. At this stage, the temperature of the mixture in the sintering zone smoothly increases from 620 to 660°C over 27 minutes. As a result, the mixture becomes less dense and has a larger pore than in the known method (approximately 0.5 mm), which will ultimately allow achieving a larger volume of closed gas/air in a unit of foam glass than in the known method.

4. Next, the process of pore formation of the mixture occurs in the temperature range of 660-780°C.

5. At a temperature of 720-765°C, the modifier in the melted batch forms solid particles.

6. Next, the process of foaming the mixture occurs in the temperature range of 780-950°C, until a soft foamed substance is obtained.

After the temperature of the mixture reaches 780°C, the glass mixture will be softened so much that it allows the released carbon dioxide to pass through itself. The volume of the substance expands. The release of carbon dioxide through the glass mass is primarily responsible for the formation of cells and pores in it. Foaming is carried out for a period of time at the maximum foaming temperature, for example, from about 780 to 950°C.

7. Next, the melt solidifies at a temperature of 950-750°C.

8. The cooling stage begins at a temperature of 750°C.

9. Immediately after this (immediately) the substance is rapidly cooled with flowing air at normal (room) temperature until the final finished material is obtained.

The glass is foamed to the required density and higher pore structure, the furnace temperature is quickly reduced to a temperature at which foaming stops. Then, using air, it is rapidly cooled until the glass experiences a "thermal shock" so that the natural crushing process occurs.

After natural disintegration (crushing), lighter stones of irregular shape with a closed air- and water-impermeable porous structure are obtained. The bulk density is 120-130 kg/m3, the thermal conductivity of the working layer (compacted) is 0.072-0.075 W/(m⋅°С)

Example 3. Obtaining fractionated foam glass material with a closed porous structure with a given bulk density of 135-145 kg/m3 and thermal conductivity of the working layer (compacted) of 0.075-0.079 W/(m⋅°C).

1. The stage of mixing the foaming component, additional components, and glass cullet flour (The proposed method allows the use of grinding with a fractional composition from 0.2 μm to 120 μm. This unique ratio of particles of different sizes makes it possible to obtain finished products with the required characteristics. Larger glass particles provide strength, since they form walls of greater thickness, which allows achieving a larger cell without deteriorating the strength characteristics).

2. - 5% foaming component (glycerin);

- silicate glass (Na2O(SiO2)n) (with a given silicate modulus M=3.27) - 7%.

Temperature control during mixing. The temperature range should be between 40-60°C.

3. After mixing, the material on the belt enters the furnace, where it is sintered at a temperature range of 620-660°C. When the batch is heated, the glass particles first soften (600…620°C), then the particles sinter - the glass mass is formed and additional contact surfaces are formed. At this stage, the temperature of the mixture in the sintering zone smoothly increases from 620 to 660°C over 26 minutes. As a result, the mixture becomes less dense and has a larger pore size than in the known method (0.3 mm), which will ultimately allow achieving a larger volume of closed gas/air in a unit of foam glass than in the known method.

4. Next, the process of pore formation of the mixture occurs in the temperature range of 660-780°C.

5. At a temperature of 720-765°C, the modifier in the melted batch forms solid particles.

6. Next, the process of foaming the mixture occurs in the temperature range of 780-950°C, until a soft foamed substance is obtained.

After the temperature of the mixture reaches 780 degrees Celsius, the glass mixture will be softened so much that it allows the released carbon dioxide to pass through itself. The volume of the substance expands. The release of carbon dioxide through the glass mass is primarily responsible for the formation of cells and pores in it. Foaming is carried out for a period of time at the maximum foaming temperature, for example, from about 780 to 950 ° C.

7. Next, the melt solidifies at a temperature of 950-750°C.

8. The cooling stage begins at a temperature of 750°C.

9. Immediately after this (immediately) the substance is rapidly cooled with flowing air at normal (room) temperature until the final finished material is obtained.

The glass is foamed to the required density and higher pore structure, the furnace temperature is quickly reduced to a temperature at which foaming stops. Then, using air, it is rapidly cooled until the glass experiences a "thermal shock" so that the natural crushing process occurs.

After natural disintegration (crushing), lighter stones of irregular shape with a closed air- and water-impermeable porous structure are obtained. The bulk density is 135-145 kg/m3, the thermal conductivity of the working layer (compacted) is 0.075-0.079 W/(m⋅°C).

When the sintering time is reduced to less than 26 minutes, the insulation has high thermal conductivity and bulk density, which limits its use. It is not practical to produce this insulation for construction.

When the sintering time increases to more than 30 minutes, the strength indicators deteriorate, and the percentage of waste increases during production, which makes the production of this insulation material economically inexpedient.

We also experimentally found that when glycerin is reduced to less than 0.5%, foaming does not occur, the glass is homogeneous, there is practically no porosity, and the resulting material is not an insulator.

And with an increase in glycerin over 5%, the number of open pores increases, which leads to an increase in moisture capacity and, as a consequence, to a deterioration in thermal insulation properties.

When the silicate glass Na2O(SiO2)n with a silicate modulus M=3.27 decreases to less than 1%, uneven pore formation occurs (the product is not foamed throughout its entire mass), which leads to a deterioration in the thermal insulation properties of the finished product. And when it increases to more than 9%, due to the fact that the silicate glass Na2O(SiO2)n is water-soluble, it leads to the destruction of the structure when interacting with water.

Tests have shown that the technical characteristics (bulk density and thermal conductivity) of fractionated foam glass obtained using methods 2, 3, 4 correspond to the specified parameters indicated in the table:

Claims (17)

1. A charge for the production of fractional insulation from foamed glass, including broken glass and glycerin as a foaming agent, as well as an additional component - silicate glass in the following ratio of components, wt.%: glycerin in the amount of 0.5-5.0, silicate glass Na ₂ O(SiO ₂ )n with a silicate modulus M=3.27 in the amount of 7-9, glass-forming component - the rest, characterized in that the glass-forming component includes different fractions of the glass-forming component from 0.2 to 120 µm. 2. A method for producing fractional insulation from foamed glass, including: - mixing of a glass-forming component of different fractions from 0.2 to 120 µm, glycerin and silicate glass Na ₂ O(SiO ₂ )n with a silicate modulus M = 3.27 at a temperature of 40-60°C with the following ratio of components, wt.%: glycerin 0.5-5.0, silicate glass Na ₂ O(SiO ₂ )n with silicate modulus M=3.27 7-9, glass-forming component of different fractions from 0.2 to 120 microns - the rest, - heating the mixture in an oven to a temperature of 600°C, - softening of glass particles of the mixture at a temperature of 600-620°C, - sintering the mixture for 26-30 minutes with a smooth increase in temperature from 620 to 660°C, - pore formation in the temperature range from 660 to 780°C, - foaming in the temperature range from 780 to 950°C, - solidification of the foamed melt in the temperature range from 950 to 750°C, - rapid cooling in the temperature range from 750 to 30°C with flowing air at room temperature to allow the natural crushing process to take place.