WO2017065648A1 - Construction material production method - Google Patents

Abstract

The invention relates to construction and pertains to the field of construction materials, and specifically to the production of any type of construction products and road pavement, and may be used in residential and commercial construction, in road construction, in casting and chemical production, and in other fields. A construction material production method includes mixing silica with a weak alkaline solution while simultaneously exposing the mixture to an electromagnetic field. Mixing is carried out until the sand is fully dissolved. The produced solution is added to a silica-containing raw material in a quantity of 4-8% of the total volume of the mixture. Further mixing is carried out until the silica-containing raw material is fully wetted. The resulting mixture is used to form products which are then dried.

Description

 METHOD FOR PRODUCING BUILDING MATERIAL

The technical field The invention relates to construction and relates to the construction materials industry, namely the manufacture of any types of construction products, pavements and can be used in housing and industrial construction, road construction, foundry, chemical production and other fields. State of the art

 Known methods for the manufacture of building material using inert aggregates in the form of crushed stone and sand, bonded with binders based on Portland cement, gypsum, water glass, clay and other materials.

 There are various technical solutions for the production of building materials, differing in the composition of the mixtures and heat treatment methods (patents US JY ° 3754952, US Ns 4234347, GB N "1277154, FR 7026259, DE N.2031268 and JP J ° 1007581).

A known method of manufacturing concrete products (RF N ° 2204476, application JS "2001129477/03, 01.1 1.2001), in which at least at one of the stages of manufacture they are exposed to an electromagnetic field, new, according to the invention, is that the pulse field is created continuously by the following packages electrical video pulses, while the duration of the packet is 2x10 ^"4 sec - 2x10 ^{" 3} sec, the duty cycle of the pulses in the packet varies in the range of 10 -100, and the specific power is 0.01-0.1 W / m ³ products. The preferred pulse duty cycle value in the packet is 20-60. The influence of an electromagnetic field is effective at the stage of hardening of the product. The best result is achieved by exposure to a pulsed electromagnetic zero at the stages and mixing of the concrete mixture and molding and hardening of the product. When implementing the method, the duty cycle of the pulses in the packet can linearly increase, linearly decrease, ramp up, or change according to another acceptable law. However, the described method does not significantly reduce the production time of building materials and requires significant energy costs, which negatively affects the cost of production. A cheaper and more progressive method of manufacturing building material is associated with the use of binders made in a separate technological process and introduced into the composition of the building material mixture during its preparation.

The closest in technical essence is the technical solution known from patent N ° 223961 1 (application ^ 2003123525/03, 07.29.2003 "Mix for the preparation of especially durable large-sized building products (options)"). In accordance with the patent, for the manufacture of a building product, a tridymite-cristobalite binder with a content of 0.1-0.2 mol% Na ₂ 0 in natural granulometry grains after firing natural quartz sand in a rotary kiln is taken and mixed with ground quartz sand to a specific surface 4800 cm ² / g, with ordinary quartz sand as a filler and reinforcing heat-treated mineral fiber with a filament diameter of 0.2-0.5 mm and its length of 50-150 mm at the content of the mixture components specified in claim 1 is added. The resulting dry raw mixture is closed with an aqueous solution of sodium hydroxide with a concentration of 5-15% and, after final mixing, samples are formed from the freshly prepared mixture, which are loaded into the autoclave with the molds and autoclaved under a pressure of saturated water vapor of 1.2 MPa for 16 hours. After hydrothermal treatment, cooled to room temperature, the samples are removed from the molds, dried at 105-1 10 ° C. The products obtained in this way have the following characteristics: compressive strength up to 1200 MPa, flexural strength up to 250 MPa, impact strength up to 7 MPa, elastic modulus up to 5.5 MPa.

 The disadvantage of this technical solution is the length of the manufacturing process of products, the use of an autoclave method for processing building materials, which significantly increases the cost of the manufacturing process. Also, the proposed method does not allow to obtain building materials with higher strength characteristics.

SUMMARY OF THE INVENTION

The technical task of the present invention is to reduce the time and energy consumption in the manufacture of building material, which leads to a reduction in the cost of products, as well as the production of various building materials with increased refractoriness and water resistance, reduced moisture absorption, high strength properties, acid resistance, neutral in relation to the effects of salts and other substances contained in the atmosphere.

The technical result of the present invention is to obtain a building material with increased strength (compressive strength from 150 kg / cm ² (15 MPa) to 1000 kg / cm ² (100 MPa), frost-resistant, acid-resistant and fireproof, while reducing the cost of manufacturing building products.

 The technical result is achieved by the fact that a method of manufacturing a building material involves mixing silica and a slightly alkaline solution, while simultaneously affecting the mixture with an electromagnetic field. Mixing is carried out until the sand is completely dissolved. The resulting solution is added to silica-containing raw materials in an amount of from 4% to 8% of the total volume of the mixture. Further mixing is carried out until the silica-containing raw materials are completely wetted. Products are formed from the resulting mixture, which are then dried.

 Fine silica with a particle size of from 20A to 0.1 mm is preferably used.

 Preferably, the drying is carried out at a temperature of from 40 ° C to 80 ° C

 It is preferable to carry out the drying by steaming the product at a temperature of from 90 ° C to 120 ° C.

 It is preferable to carry out the drying by exposing the article to microwave radiation.

 Expanded perlite or vermiculite is preferably added to the silica-containing raw material. Such additives allow to obtain a building material with low thermal conductivity.

 It is preferable to add granite chips to the silica-containing raw materials. It is preferable to add marble chips to the silica-containing raw materials.

Adding granite and marble chips to the mixture allows you to get finishing building materials with imitation of granite or marble stone.

 The specified technical result is achieved by the totality of the claimed features.

Embodiments of the invention In the following, the claimed technical solution is illustrated by a detailed description of specific but not limiting the present solution, examples of its implementation and the attached drawing, which schematically shows a device for producing a binder.

A method of manufacturing a building material is as follows. The initial step of the method is the manufacture of a binder; for this purpose, silica and a weakly alkaline solution are mixed, for example, alkali metal hydroxide or ammonium hydroxide, while the concentration of a weakly alkaline solution does not exceed 5%.

 As silica, crushed stone crushing waste can be used - dust or sand with a quartz content of at least 65%. It is preferable to use silica finely ground with a particle size of up to 0.1 mm, which further reduces the mixing time of the mixture, reduces energy consumption, which reduces the cost of building material.

 In the method according to the invention, for producing a slightly alkaline solution, fresh, for example, industrial water, sea water, mineralized water is used, which makes it possible to use the method according to the invention in various environmental conditions, as well as to utilize various technical water, thereby improving the ecology.

 Mixing of the starting components is carried out when exposed to an electromagnetic field. To create such conditions, a device was developed and manufactured.

 The figure shows a diagram of a device for producing a binder according to the invention. The binder is prepared in a high-speed flow-type grinding device, circulating the mixture in a closed circuit with its repeated passage through the vortex of ferro-magnetic particles created by the electromagnetic field, and through the dispersing apparatus of the device.

Silica (or dust) is loaded into the receiving hopper 1 through a conduit 6, and a weakly alkaline solution, for example, an alkali metal hydroxide or ammonium hydroxide solution, is charged through a conduit 7. After mixing the components in the receiving hopper, the mixture, through line 8, is fed to the disperser pump of the homogenizer 2, after passing through which the mixture is fed into the electromagnetic activator 3 through the pipe 9. Here, the mixture is subjected to an activating treatment in the working zone, which is made in the form of a pipe with a diameter of 50 to 150 mm, with ferro magnetic needle particles that are constantly held in the working area of the apparatus by a magnetic field. Under the influence of an external electromagnetic field, the needles move along the working zone, colliding with the particles of the mixture. In this case, the effects of acoustic waves (from 20,000 Hz to 40,000 Hz Hz), magnetostriction, mechanostriction and cavitation with high specific power are generated. As a result, the particles of the mixture are intensively mixed with simultaneous grinding to micron and submicron sizes, active, accelerated physical and mechanical processes of amorphization and dissolution of silica occur in the mixture. The power of the electromagnetic activator, depending on its volume, is from 2.6 kW to 20 kW. Processing the mixture in an electromagnetic field is carried out depending on the volume of the mixture for 3 minutes to 10 minutes. Such electromagnetic activation of the mixture requires significantly less time and energy costs. After passing through the filter 4, the binder pipe 1 1 can be fed to a reprocessing. For complete dissolution of silica, depending on the particle size of the silica used, no more than three cycles are sufficient. After complete dissolution of the silica, the obtained binder through the valve 5 by a pipe 12 is fed into the dispenser, and then into the mixer, into which the silica-containing raw material is already filled.

 The resulting binder is used in an amount of from 4% to 8% of the total volume of the mixture. Mixing is carried out at normal speed in mixers, eliminating sticking to the walls and working bodies (two gross, planetary, etc.) When using a binder less than 4% of the total volume of the product mixture, there are places where dry components are poorly glued to each other, which leads to decrease in strength. With an increase in the binder of more than 8%, the strength of the resulting products decreases.

Any mineral natural substances with a silica content of at least 65% are used as silica-containing raw materials, the most acceptable are screening crushed stone, coarse, medium and fine or ground sand, diatomite, tripoli, marshalite, flasks and others. At the same time, it is good to add up to 15% cristobalite to the composition of the mixture in the form of solid pulverized waste from metallurgical industries and coal-fired boilers, which are captured from exhaust gases and smoke (silica fume). You can get cristobalite directly in the production process by short-term (1 - 3 sec) firing of silica (sand or dust) at a temperature of from 800 ° C to 1200 ° C. At the same time as silica-containing raw materials, expanded perlite or vermiculite can be added to the mixer to obtain products with low thermal conductivity, that is, to obtain building materials with good thermal insulation properties, and marble or granite chips are added to the mixture to obtain decorative products with an original pattern on the surface. .

Mixing is carried out until the silica-containing raw materials are completely wetted with a binder. Then, from the resulting mixture, the products are molded by the method of simple or hyper-pressing, by vibro-pressing, by the shock-pressing method, or by another known method, and construction products of any shape are obtained. The molded products are dried at a temperature of 40 - 80 ° C for 1 - 2 hours, if necessary, or (to obtain special properties) are treated with steam at a temperature of 90 - 120 ° C at atmospheric pressure or fired at high temperatures depending on the type of product and its destination. The most effective hardening of building material is obtained by processing molded products with electromagnetic fields of ultra-high frequency (microwave). So products having a weight of up to 5 kg., Achieve compressive strength of 150 - 200 kg / cm ² for 5 minutes, and 500 - 700 kg / cm ² for 30 minutes. The parameters of the molding sand, drying and heat treatment are determined by the technological regulations for the manufacture of a particular product.

 To implement the method according to the invention, various grinding devices and various mixing and dispersing devices are used, which provide preliminary grinding of silica-containing raw materials and effective mixing of the initial mixture. These devices include centrifugal impact, ball, roller and disk mills, various dissolvers, bead mills; high-speed mixers - disk mixers, disk-propeller and disk-paddle mixers, mixers with an anchor mixer, high-speed rotor-stator mixer, planetary mixer, screw, planetary mixers with three-dimensional movement of spiral-tape working bodies.

 Examples of the method according to the invention.

Example 1. In the serial and mass production of building products (wall materials - bricks, facing and paving slabs, etc.) weighing from 0.5 to 5 kg.

To obtain a binder: in the installation, (depending on the volume of production cyclically or constantly), crushing dust of crushed stone or sand (utilized waste from other industries) - with a silica content of at least 60% and a particle size of up to 1 mm, and a slightly alkaline solution of sodium hydroxide with a concentration of 5%. To obtain a solution of water, you can use fresh, marine or technical. The ratio of dry and liquid components 1/1. The mixture is treated as described above for 10 minutes.

 To obtain a molding mixture: silica-containing raw materials must have the particle size distribution necessary to obtain a close-packed matrix. Depending on the availability of the source of raw materials, silica-containing raw materials consists of screening crushing gravel or coarse sand (1-Zmm) and fine sand in a ratio of 1/1. The raw material mixture is loaded into the mixer and cristobalite is added, in the form of silica fume, to obtain products of dark gray or black colors, in the form of tripoli, to obtain products of white flowers, in the form of a flask, to obtain products of light beige or brown colors, in the amount of 5% up to 10% of the volume of the raw mix (depending on the required strength and color of the products). These components are pre-mixed in dry form. After that, a binder is added to the raw material mixture in a volume of 4% - 8% of the total volume of the mixture (strength characteristics in this range do not change, and the required volume is adjusted based on the moisture content of the feedstock, the higher the moisture content of the raw material mixture, the lower the volume of the binder). Stirring is carried out until the composition is completely wetted with a binder for 5 to 10 minutes. The resulting mixture is molded by simple pressing, vibration or hyperpressing, drying is carried out by processing the molded products in a through or dead end microwave oven immediately after removal of the products from the press. The resulting products have the following characteristics:

Tensile strength MPa - 30

 Tensile strength Bt, MPa - 2.8

 Frost resistance P, number of cycles - 200

 Acid resistance according to GOST 473.1-72,%, not less than 99

 Water and acid absorption,%, no more than 2.4

 Refractoriness, ° С 1700

 Thermal resistance, the number of heat - shifts (1200 degrees) 20

 Temperature growth,%, no more than 0.5

Residual compressive strength after firing, at 1200 ° C, not less Mohs hardness, up to

The table below shows the characteristics of the materials obtained during the experiment, which were manufactured as described in the example, but have a different amount of binder from 3% to 9%. The table shows that going beyond the stated limits in terms of the quantitative composition of the binder worsens the characteristics of the finished material.

 Table

Example 2. Production of concrete products weighing up to 2 tons.

A binder is prepared as described in Example 1. Silica-containing raw materials have the following ratio: granite crushed stone (10

- 30 mm) 20% of the volume, crushing screenings (up to 10mm) 40% of the volume, fine sand 17% of the volume of silica fume or any other kind of cristbalite 15% of the volume. The dry mixture is mixed in the mixer until uniform, after which a binder of 8% by volume is introduced into the mixer. Mixing is carried out until the dry components are completely wetted with a binder.

 The resulting mixture is formed by vibro-laying with a load or horizontal vibroforming. Drying is carried out by steaming at a temperature of 120 ° C - 180 ° C for 2 to 12 hours (depending on the weight of the product) or microwave drying for 2 hours. Dried under normal conditions for 2 hours.

 The resulting product has the following characteristics:

 Tensile strength MPa - 100

 Tensile strength Bt, MPa - 3.2

 Frost resistance P, the number of cycles - 500 Acid resistance according to GOST 473.1 -72,%, not less than 99

 Water and acid absorption,%, no more than 2.4

 Refractoriness, ° С 1700

 Thermal resistance, the number of heat - shifts (1200 degrees) 20

 Temperature growth,%, no more than 0.5

 Residual compressive strength after firing, at 1200 ° C, not less than 100%

Mohs hardness, up to 7

Example 3. The manufacture of thermal insulation boards.

 A binder is prepared as described in Example 1.

To obtain a molding mixture: silica-containing raw materials consist of coarse sand (1-3 mm) and fine sand in a ratio of 1 / 1-60% of the volume, expanded perlite (or vermiculite) - 31% of the volume and cristobalite (silica fume, tripoli and t .d.) 5% of the volume. The raw material mixture is loaded into the mixer and pre-mixed in dry form. After that, a binder in a volume of 4% of the total volume is added to the raw material mixture. Stirring is carried out until the composition is completely wetted with a binder for 7 minutes. The resulting mixture is formed by simple pressing. Drying is carried out by processing molded products in continuous or dead-end microwave oven immediately after removal of products from the press. The resulting products have a thermal conductivity of not more than 0.175 W / MhK while maintaining all the strength characteristics:

Tensile strength MPa - 30

 Tensile strength Bt, MPa - 2.8

 Acid resistance according to GOST 473.1 -72,%, not less than 99

 Water and acid absorption,%, no more than 2.4

 Thermal resistance, the number of heat - shifts (1200 degrees) 20

 Temperature growth,%, no more than 0.5

 Residual compressive strength after firing, at 1200 ° C, not less than 100%

Mohs hardness, up to 7

Industrial applicability

 Products obtained by the claimed method can be used as any building materials with high technical characteristics, namely with increased refractoriness and water resistance, reduced moisture absorption, high strength properties, acid resistance, neutral with respect to the effects of salts and other substances contained in the atmosphere. Moreover, the claimed method allows to reduce the time of manufacturing products and reduce energy costs for their manufacture. With high strength characteristics of the product have a low cost.

Claims

CLAIM. 1. A method of manufacturing a building material, including mixing silica and a slightly alkaline solution, while simultaneously affecting the mixture with an electromagnetic field, mixing is carried out until the silica is completely dissolved, the resulting solution is added to silica-containing raw materials in an amount of 4% to 8% of the total mixture, then mixed until the silica-containing raw materials are completely wetted, the products are molded from the resulting mixture and dried. 2. A method of manufacturing a building material according to claim 1, characterized in that fine silica with a particle size of up to 0.1 mm is used. 3. A method of manufacturing a building material according to claim 1, characterized in that the drying is carried out at a temperature of from 40 ° C to 80 ° C 4. A method of manufacturing a building material according to claim 1, characterized in that the drying is carried out by steaming the product at a temperature of 90 ° C - 120 ° C. 5. A method of manufacturing a building material according to claim 1, characterized in that the drying is carried out by exposing the product to microwave radiation. 6. A method of manufacturing a building material according to claim 1, characterized in that expanded perlite or vermiculite is added to the silica-containing raw material. 7. A method of manufacturing a building material according to claim 1, characterized in that granite chips are added to the silica-containing raw materials. 8. A method of manufacturing a building material according to claim 1, characterized in that marble chips are added to the silica-containing raw materials.