RU2710061C1 - Method of producing foam concrete - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: invention relates to production of construction materials and can be used to produce heat-insulating materials. Method of producing foam concrete includes preparation of a suspension of a silica-containing component by electrohydraulic dispersion in water of glass breakage to specific surface of not less than 3,500 cm²/g and maximum particle size of not more than 100 mcm, modification of the obtained suspension by successive introduction of caustic alkali and a plasticising additive, its mixing with the preliminary prepared technical foam by treatment in the foaming agent of an aqueous solution of a protein foaming agent, molds are filled and dried at the following ratio of components, wt%: ground glass 65–80, caustic alkali 0.05–1, plasticising additive 0.05–2, protein foaming agent 0.2–2, water – the rest. Method envisages preparation of a suspension by electrohydraulic dispersion in water with pH 10.5–12.

EFFECT: use of secondary raw materials, low power consumption while maintaining high physical and mechanical properties.

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Description

The invention relates to the production of building materials and can be used to obtain insulating materials.

A known method of manufacturing foam concrete (RF patent No. 20186884, publ. 07/30/1994), including whipping the foam by mixing at a speed of 800-850 rpm foaming agent and silica-containing component, part of the water from the total water demand and subsequent mixing of the foam with a finely divided silica filler, surfactant and the remaining water, pouring the mixture into a mold, autoclave hardening, characterized in that, in order to reduce the density, 40-45% of the total water demand is mixed with whipping foam, aluminum production waste th foil and alkali-free glass with a specific surface of 2000-2500 cm ² / g, and the foam is mixed at a speed of 500-600 rpm with a pre-prepared solution of the remaining water, alkaline glass with a specific surface of 4200-5000 cm ² / g and surface-active substances, while the resulting foam concrete mixture contains these components in the following ratio, mass. %: alkali-free glass 8-12%; alkaline glass 50-56%; 4-6% aluminum foil production waste; Surfactant 0.03-0.04%; water the rest.

The disadvantages of this method are the use of autoclave processing, which significantly increases the cost of obtaining the final product, and the use of alkali-glass battle, which presents technological difficulties due to its small and heterogeneous content in the total mass of glass waste.

A known method of manufacturing ultralight foam concrete (RF patent No. 2138465 publ. 09/27/1999), comprising dosing the initial components of sand slurry containing ground quartz sand, cement and a foaming agent, mixing them and filling forms, characterized in that the ground quartz sand is used with specific a surface of at least 2900 cm ² / g, cement is mainly of the M500 brand, and as a foaming agent it is predominantly FOAMCEM, the molds are filled predominantly with a pump; dispensers of periodic action and stirred for 1 -5 minutes, and then add a foaming agent and mix for 3-8 minutes, and dosage, mixing and filling of the forms is carried out at a temperature of 15-30 ° C.

The disadvantage of this method is the use of cement, which significantly increases the cost of obtaining the final product. In addition, cement and sand are the primary resources, and their use enhances the negative human impact on the environment.

As a prototype, a method of manufacturing foam concrete products is adopted (RF patent No. 2412136, publ. 02.20.2011), which includes the preparation of technical foam by mechanical treatment in a foam generator - mixer of an aqueous solution of a foaming agent, mixing it with a cementless nanostructured binder - a highly concentrated suspension of silica-containing raw materials, molding from the obtained foam mass of products, hardening and drying, characterized in that they use the specified suspension with a particle content of less than 5 microns, comprising 20-50%, and with a moisture content of 12-20%, previously subjected to modification by successive administration of an organo-mineral additive in an amount of 0.02-0.10% and a plasticizing additive in an amount of 2-5% by weight of the dry matter of the suspension, and as a foaming agent, a protein foaming agent, the following ratio of components, mass. %: the specified binder (on dry matter) 68.87-77.7; protein foaming agent 0.60-1.53; water 21.63-29.60, hardening is carried out by immersion with short-term exposure of the product after drying in an alkaline silicate solution with a density of 1.06-1.08 g / cm ³ for up to 3 minutes, followed by final drying.

The disadvantages of this prototype are the difficulty of obtaining a highly concentrated suspension of silica-containing raw materials of the desired composition, the strong dependence of product characteristics on the composition and origin of silica-containing raw materials.

The aim of the invention is the use of secondary resources and reducing energy consumption in the production of heat-insulating materials.

This goal is achieved by the fact that in the method of manufacturing foam concrete, which includes preparing a suspension of a silica-containing component, preparing technical foam by treating an aqueous solution of a foaming agent in a foam generator, mixing, filling out forms and drying, glass breakage is used as a silica-containing component, the suspension is prepared by electro-hydraulic dispersion into water silica-containing component to a specific surface of not less than 3500 cm ² / g and a maximum particle size of not more than 100 m km, the specified suspension is subjected to modification by sequential introduction of caustic alkali and plasticizing additives, and as a foaming agent, a protein foaming agent is used in the following ratio of components, mass. %: ground glass 65-80, caustic alkali 0.05-1, plasticizing additive 0.05-2, protein foaming agent 0.2-2, the rest of the water. Moreover, depending on the method, a solution of caustic alkali with a pH of 10.5-12 can be used to disperse the silica-containing component.

The method is as follows.

For the production of foam concrete, glass breakage is used, which is a mixture of mainly tare, window and pan glass, the main composition of which is expressed by the formula Na ₂ O⋅CaO⋅6SiO ₂ . Sodium oxide is contained in the range of 14-16%, calcium oxide is in the range of 5-8%. Also, the composition of these glasses includes oxides of aluminum, magnesium, potassium, in total no more than 7%. Other elements and substances are contained in small quantities.

Fine grinding of glass is carried out through the use of the electro-hydraulic effect, open L.A. Yutkin in the 1930s. The essence of the electro-hydraulic effect phenomenon is that in the zone of the generated high-voltage pulse discharge in a liquid medium, high hydraulic pressure and temperature arise, which are accompanied by shock waves, pulsed cavitation processes, and powerful electromagnetic fields. Due to these phenomena, grinding of glass particles and their mechanochemical activation occurs.

The glass break is pre-washed and ground in mechanical grinders to obtain a fraction of 1.5-3 mm. Grinding glass to a given size mechanically requires less energy than electro-hydraulic. Next, the obtained material is fed into the working capacity of the electro-hydraulic installation, filled with water and subjected to dispersion by applying high-voltage pulses to the working interval in the following modes (sequentially):

1) U = 20-30 kV, C = 0.5-3 μF (the so-called "soft mode");

2) U = 35-45 kV, C = 0.3-1 μF (the so-called "medium mode");

3) U = 50-65 kV, C = 0.1-0.5 μF (the so-called "hard mode").

For processing larger fractions, a milder mode is used, and for smaller fractions, a more stringent one is used. Electro-hydraulic processing can be performed both in a closed, non-flowing container without separation of the crushed fraction, and with the separation of the crushed fraction and its supply to the treatment zone in a more stringent mode. In the latter case, the energy efficiency of the process increases. Dispersion is carried out to obtain a specific surface area of at least 3500 cm ² / g and a maximum particle size of not more than 100 microns.

After removal of excess moisture, caustic alkali in the form of sodium or potassium hydroxide is introduced into the resulting suspension. It is possible to add caustic alkali to water to disperse the glass to obtain a pH of 10.5-12, then in this case the amount of caustic alkali introduced into the suspension is significantly reduced. To increase the mobility of the mixture, a plasticizing additive is introduced into the suspension in an amount of 0.05-2% wt.%. Next, the resulting suspension is mixed with pre-prepared foam based on a protein foaming agent and poured into molds for hardening at an ambient temperature of at least 20 ° C. Strengthening occurs due to alkaline silicate reactions of hydrolysis and glass hydration in an alkaline environment.

After 24 hours, the products are removed and subjected to final drying at an ambient temperature of at least 20 ° C or in a drying chamber at a temperature of 40-100 ° C.

For testing, samples were made - cubes with a side of 100 mm with a density of 350 and 500 kg / m ³ . Tests of the samples showed at a density of 500 kg / m ^{3 the} strength of 1.1 MPa, thermal conductivity of 0.12 W / K, and at a density of 350 kg / m ^{3 the} strength of 0.7 MPa, thermal conductivity of 0.09 W / K.

Claims (5)

1. A method of manufacturing a foam concrete, comprising preparing a suspension of a silica-containing component, preparing technical foam by treating an aqueous solution of a foaming agent in a foam generator, mixing them, filling out forms and drying, characterized in that glass breakage is used as a silica-containing component, the suspension is prepared by electro-hydraulic dispersion in water silica-containing component to the specific surface area of at least 3500 cm ² / g and a maximum particle size less than 100 microns, said uspenziyu subjected to modification by sequentially adding caustic alkali and plasticizing additives, and is used as a foaming agent proteinaceous foaming agent with the following ratio of components, wt.%: ground glass                          65-80 caustic alkali                                     0.05-1 plasticizer 0.05-2 protein foaming agent   0.2-2 water                                          rest 2. The method according to claim 1, characterized in that the suspension is prepared by electro-hydraulic dispersion in water with a pH of 10.5-12.