Method of production of calibrated granulated foamed glass

FIELD: manufacture of building materials at low heat conductivity and density; production of granulated foamed glass from non-assorted broken glass at form of granules close to ball-shaped.

SUBSTANCE: initial raw mixture is made from aqueous alkaline solution of sodium silicate in the amount of no less than 30-70 mass-% and broken glass powder of arbitrary chemical composition in the amount of 25-65 mass-%. This raw mixture is subjected to heat treatment to dehumidified state and powder-like charge and aqueous dispersion are prepared in presence of plasticizing agents. Product thus obtained is dried at dried at temperature of 450-500°C, pelletized and is held at foaming temperature within range of 800-850°C.

EFFECT: reduced labor consumption and power requirements.

4 cl, 1 tbl, 1 ex

The invention relates to the production of building materials with low values of thermal conductivity and density, in particular for the production of calibrated foam glass granulate from recycled cullet without regard to its chemical composition.

The foam glass can be obtained in many ways with the use of compositions based on various glass and foaming agents. The powder produced either from specially welded glass melting, or from the breakage, tare, optical and other glasses. Traditional technology of production of foam glass includes a glass of special composition, milling with a blowing agent to obtain a finely dispersed mixture, the foaming molded mixture in the annealing process at a temperature not less than 700° (US 4192664, CL 03 In 19/00, 1980, US 3403990, CL 65-22, 1968). Application of known technology allows to receive the glass sufficiently high quality with uniform structure, providing operational stability, however, produce foam glass has a high cost due to the complexity of the operations produce glass of the desired composition.

In the patent US 4198224, CL 03 In 19/08, 1980, disclosed multi-stage energy-intensive method of producing foamed glass from cullet comprising heating the powder mixture to a temperature of the foaming granted the HCS at this temperature until completion of the foaming process and the subsequent cooling. Foam glass is manufactured by the Pittsburgh Coming Corporation, obtained from the fine powder of glass that is to be disposed, and the gasifier. Glass of a specific composition and a blowing agent, which is in a solid phase, separately milled and mixed in a ball mill. The obtained powdery mixture then is sintered in two stages at a temperature below the foaming and cool. The known method is complicated by the fact that it is associated with the problem of mixing the starting components in the solid state phase that does not provide them with high uniformity of distribution in the volume of the mixture. In addition, the grinding in metal mills leads to contamination of the mixture of metal balls and lining that violates the terms of steam formation in the stage production of foam glass. Unfortunately, in the conditions of rising energy prices using known powder charge and how you can get leads to higher cellular glass. This requirement imposes constraints on the choice subjected to foaming of the composition.

In document WO 00/61512, 03 11/00, 2000 disclosed a method of obtaining a granulated foam glass using waste glass with one - or two-stage processing of the granulate at a temperature of 200 to 300°or 400-800°With in a period of time not more than 15 minutes.

Liquid glass is known as an additive when PR is the production of foam glass granulate, necessary as a binder for the pellets (e.g., DE 2010263, 03 11/00, 1979). In the patent RU 2162825, CL 03 With 11/00, 2001 disclosed a method of making foam glass from disassembled the broken glass of a specific composition, comprising preparing a mixture by joint grinding of broken glass and blowing agent, granulating the mixture with irrigation water solution of soluble glass.

From the patent RU 2109700, CL 03 With 11/00, 1998-known technology of production of foam glass granulate from a raw mixture containing 53,22-71,26 wt.% glass waste, blowing agent and a binding agent. The glass is made by grinding glass and the gasifier, two-stage granulation on the movable surface of the granulator while filing binders and subsequent annealing. Stage granulation involves the preliminary formation of the so-called germinal granules from a mixture of waste triplex and gasifier and subsequent granulation obtained germinal granules simultaneously with the foaming mixture containing ground triplex and the gasifier. Granulation is carried out in the mode specified ratio of the diameters of the embryo and the resulting raw granules. The known method does not allow to obtain calibrated granulated foamed glass, i.e. glass with predetermined and uniform size and shape Gras is Olami. How bad reproduce because of its feasibility associated with the implementation of hard controlled run mode, the ratio of the diameters of the embryo and the resulting granules.

One of the interest of the ways to obtain granulated foam glass is the method according to the patent of the Russian Federation 216825. The known method includes the cullet crushing, washing and drying at a temperature of 110-120°, batching and joint grinding of broken glass and blowing agent, granulating the mixture on a plate granulator with irrigation water solution of soluble glass, drying the pellets to a tape-mesh dryer at a temperature of 400°to a moisture content of 2%, the foaming pellets in a rotary kiln with river quartz sand as a separating medium at a temperature of 780-820°and separating the granules from the separating medium. There is a method allows to simplify the method for the production of foam glass granulate and reduce energy consumption, but it also allows you to get a uniform in size and shape of the granules of foamed glass in the party. A serious limitation of this method is the significant number of fractured granules, as well as its low reproducibility and high bulk density, a component of 200-300 kg/m³due to the application of damp raw material mixture.

In the patent of the Russian Federation 2187473, CL 03 In 19/08, 2000 is. disclosed is a method of obtaining granulated foam glass, including a preliminary heat treatment at a temperature below the foaming of the mixture obtained from the fine powder of glass, carbon-containing component and sodium silicate, heating the mixture to a temperature of foaming, holding at that temperature to complete the process of foaming and subsequent cooling. In the known method mix dispersible cullet on the basis of alkaline aluminosilicate glassy waste and foaming the mixture containing silica, carbon-containing component, a metal sulfate and a liquid sodium glass in the amount of 0.5-5.0 wt.%. Liquid glass is used in a dry or moistened with water to improve the gathering of the material into pellets. Fill the metal forms a granular material and sent to the sintering furnace. Obtained by known techniques granulated foamed glass is characterized by high cost associated with the need for long and complicated mechanical mixing of the components to a very uniform distribution of the particles of the foaming agent in the powder. In addition, the grinding in metal mills leads to contamination of the charge of the metal balls and the lining, which further violates the terms of steam formation in sintering the first mixture. Technological regimes known method worked out in relation to the specific composition of the glass, which makes them unacceptable when using cullet arbitrary composition. In a known manner it is impossible to obtain a calibrated granulated foamed glass, i.e. glass with predetermined and uniform size and shape of the granules. Way bad play, because its application does not allow to obtain a homogeneous initial size nesperennub granules.

In the framework of this proposal solves the problem of the development of technology for calibrated foam glass granulate, allowing reproducibly obtain granules with a shape close to spherical, and the specified size. There is also a need to expand the resource base and development of such technology, which would allow to produce a homogeneous chemical composition, size and shape of the foam glass granules without regard to the chemical composition of the glass, i.e. of mixed cullet. There is a need to develop technologies with low energy intensity of production. In addition, the task of improving the reproducibility of the patterns of granulated foam glass with a homogeneous porous structure containing pores of a closed form.

This object is achieved in that a method of obtaining a calibrated granules is fragmented foam comprises mixing at a temperature not exceeding 70° With aqueous alkaline solution of sodium silicate and/or potassium, powder of glass and carbon-containing component, the heat treatment is obtained by mixing a plastic mixture at a temperature of 450-550°to obtain a dehydrated composition, the subsequent grinding of the cooled composition in powder and the preparation of an aqueous dispersion of a powder with the addition of plasticizer, drying the dispersion at a temperature of 450-500°, tableting the resulting product is drying and heating it to a temperature expansion of the range of 800-850°S, shutter speed preformed product at a temperature of foaming and cooling to ambient temperature.

It is advisable to mix the raw ingredients in the ratio, wt.%:

Preferably the aqueous dispersion is prepared with a water content of 70-75 wt.%.

In addition, cooling the preformed product temperature foaming lead at a rate of 0.5-1.0 deg/min

Since unsorted cullet, i.e. artificial technical glass, are systems containing the hypoxia oxides, the process of interaction in aqueous alkaline solution of sodium silicate and unsorted cullet demanded study its thermodynamic regimes. Dissolved in water to a concentration of sodium silicate and/or potassium is an alkaline solution, which is necessary for the occurrence of physico-chemical processes involved in its interaction with oxides of cullet, regardless of their composition, including the content in the glass of alkaline oxides.

The invention consists in establishing a causal relationship between physico-chemical properties of the calibrated foam glass granulate, thermodynamic modes of obtaining the raw material mixture, the aqueous dispersion of the powder cooled mixture and plasticizer, and subsequent pelletizing product drying this dispersion and thermal expansion. In the absence of well-known patterns of physico-chemical state of matter after it is processed at a temperature of foaming in the form of tablets from the original ingredients in obtaining raw material mixture, the authors experimentally were found the optimal sequence of operations of the method and content of the aqueous alkaline solution of sodium silicate in the original mixture, which allow for subsequent processing at a temperature in the range 50-550° To get the required parameters calibrated foam glass granulate. In the absence of the strict theory of the viscosity of the dispersion system of the above regularities in the preparation of the raw mixture was performed empirically.

In this method of obtaining calibrated foam glass granulate mixing of silicate of alkali metal, powder technical glass arbitrary chemical composition and carbon-containing the blowing agent is carried out not in the solid state and in aqueous alkaline solution of sodium silicate and/or potassium, representing a plastic fluid indicator medium pH>7 and which is such a component that provides a uniform distribution of the powdered additives by volume of the mixture, and passing the required physical and chemical processes. Heating the initial mixture to a temperature of 450-550°lead to dehydration and removal of chemically bound water. Mixing the source component of the mixture in the state of liquid phase at a temperature not exceeding 70°allows to obtain a uniform volume of foam glass structure closed gas-filled pores at low intensity of production without regard to the chemical composition of technical glass.

This method allows you to produce granulated foamed glass in the form of porous gr is zero given size (gauge) and a spherical shape with a diameter of 7 mm to 40 mm, with high mechanical strength. If necessary, the size of spherical granules can be increased.

Each pellet obtained in this way foam on the outer surface of the protective layer, which may be made of different materials - silica sand of various fractions of cement. This layer gives granular foam glass additional properties chemical and heat resistance, and provides better adhesion of the foam glass with different binders when used as fillers in various products, such as cement mortar, concrete.

Produced in this way is calibrated granulated foamed glass has all thermal and mechanical properties of a block of foamed glass according to the coefficient of thermal conductivity in the respective ratios of the strength/the volumetric weight exceeds the figures of the last 10-15%.

For a better understanding of this invention the following is a specific non-limiting example of a method of obtaining a calibrated foam glass granulate.

Example

The initial mixture is prepared from the following components. As the source of ingredient use 150 kg of commercially available, i.e. commercially available, aqueous alkaline solution of sodium silicate is potassium (optimal ratio of 1:1), custom Ryazan plant of Tripoli autoclave or bezavtoklavnym method hydrothermal leaching of oxide of silica in an alkaline medium (pH>7) at a temperature of 90-100°C. an Aqueous solution of sodium silicate and potassium (optimal 1:1 ratio) when the ambient temperature is first stirred for 10-15 minutes with a fine-grinded powder unsorted cullet different grades and chemical composition, taken in an amount of 65 kg. To the resulting plastic composition add 20 kg of carbon gasifier. During mixing of the composition is the binding free water and alkali, adversely affecting the solubility of the final product - foam glass. The resulting mixture has a gray color. After mixing of all the components of the raw material mixture carried out the heat treatment at a temperature of 520°C for 65 minutes. When the heat treatment be further physico-chemical processes, accompanied by the removal of free hydrated and chemically bound water and increase the viscosity of the mixture, after which it becomes dark grey. Weight cooled to the ambient temperature of the raw mix is about 60% by weight of the starting components. Then carry out the grinding of the mixture to the size of grain of 15-20 μm and prepare a water dispersion of a mixture with additives plasticized the RA. The water content of the dispersion to about 72 wt.%. The resulting dispersion is treated in a vertical drying-granulation installation at a temperature of 470°From turning into dehydrated mass in the form of so-called "microcopy". The resulting product drying tabletirujut with the magnitude of the tablets with a diameter of 10-12 mm Obtained tablets are served in a rotary furnace in which keep the temperature of the foaming 830°C. After cooling the temperature of the foaming about 0.6 deg/min at the outlet of the furnace get calibrated granulated foamed glass with the form of granules, is close to spherical, with all the properties of high-quality thermal insulation of foamed glass.

Table 1 shows the results of comparative tests a block of foamed glass and calibrated foam glass granulate obtained by this technology.

The developed method allows to obtain calibrated granulated foamed glass with the form of granules, is close to spherical, reproducible dimensions of finely porous structure of cullet arbitrary chemical composition. The production of calibrated foam glass granulate with a spherical shape of the pellets allows the maximum extent possible to fill any teploizolyatsii volume design, which greatly improves its mechanical and operational properties, and in the manufacture of concrete and/or concrete products and structures - significantly reduces the specific consumption of cement or other binding material.

The invention involves the use of aqueous alkaline solution of sodium silicate and/or potassium and reactive to him additives, one of which is a powder with whom kloba arbitrary chemical composition, lets get after them mixing with the carbon-containing blowing agent and heat treatment at a temperature of 450-550°dehydrated composition suitable for obtaining calibrated foam glass granulate with high heat insulation properties, but with low energy intensity of production by eliminating special cooking on the chemical composition of the glass at high temperatures.

1. The method of obtaining calibrated foam glass granulate, comprising mixing at a temperature not exceeding 70°With an aqueous alkaline solution of sodium silicate and/or potassium, powder of glass and carbon-containing component, the heat treatment is obtained by mixing a plastic mixture at a temperature of 450-550°to obtain a dehydrated composition, the subsequent grinding of the cooled composition in powder and the preparation of an aqueous dispersion of a powder with additives plasticizers, drying the dispersion at a temperature of 450-500°, tableting the resulting product is drying and heating to a temperature expansion of the range of 800-850°S, shutter speed preformed product when the foaming temperature and cooling to ambient temperature.

2. The method according to claim 1, where the ingredients with stirring chosen ratio, wt.%:

3. The method according to claim 1, where the aqueous dispersion is prepared with a water content of 70-75 wt.%.

4. The method according to claim 1, characterized in that the cooling preformed product temperature foaming is conducted at a rate of 0.5-1.0 deg/min