RU2743900C1 - Method of producing composite carbon radar absorbing product - Google Patents

Abstract

FIELD: radio mechanic.SUBSTANCE: invention relates to methods of producing composite materials absorbing electromagnetic waves, which are composite materials based on highly porous mineral fillers and electrically conductive particles. The method of obtaining a composite material absorbing electromagnetic waves includes the process of mixing the components: a highly porous mineral filler with a density of no more than 0.2 g / cm3 in an amount of 50-82% of the volume, an electrically conductive material 1545% of the volume, a binder 38% of the total volume of the mixture at 1300 rpm -1500 rpm for 35-45 minutes.EFFECT: invention improves efficiency of the method for producing a composite material absorbing electromagnetic waves.1 cl, 7 tbl

Description

The invention relates to means for absorbing electromagnetic energy, which are composite materials based on highly porous mineral fillers and electrically conductive particles, which, in a mixture with organic and inorganic binders, form radioprotective materials for construction purposes, also relates to methods for producing such materials

The invention can be used for the production of lightweight construction concrete, plaster and masonry mortars used in construction and finishing works in order to reduce the level of the electromagnetic field (EMF) inside the premises.

A known method of producing electrically conductive concrete, including mixing cement, powdered graphite and sand, followed by adding water to the mixture and mixing to obtain a mixture, shaping and drying until complete solidification, in which the powdery graphite is first mixed with cement, then with sand, and drying lead at room temperature, and the mixture contains components in the following ratio, wt. %: powdered graphite 25-35, cement 20-30, sand 25-45, water - the rest (RU 2291130 C1, 10.01.2007).

The disadvantage of the above materials is the use of graphite powder as an electrically conductive filler.

The minimum size of graphite particles in powders of such a dry colloidal-graphite preparation is 1-10 microns, while the specific surface area of the particles does not exceed 3 m ² / g, which affects the efficiency of attenuation of electromagnetic radiation (hereinafter EMP) and requires the use of high concentrations of graphite for obtaining through conduction (quantum effects). The high content of graphite in such a material causes a sharp rise in the cost of the material and deterioration of its mechanical properties. In addition, graphite-filled materials (concrete, plaster layer) attenuate EMP mainly through surface reflection (shielding). Such shielding does not solve the problem of protecting a person from an increased level of EMP, since in this case the electromagnetic wave only changes the direction of propagation. By protecting any object in this way, especially in the case of dense construction of a megalopolis, due to the superposition and resonance of reflected waves, it is possible to obtain local fields around the object, the intensity of which is much higher than the intensity of the incident EMP and the permissible standards. A similar effect can occur indoors in which the equipment that generates EMF is operating. Radioprotective material for collective protection against EMI should absorb rather than reflect EMP.

From the theory of propagation of electromagnetic waves, it is known that porous materials have a low EMP reflection coefficient due to close values of the wave resistance of the material surface and the surrounding air: reflection and refraction of electromagnetic waves occur at the interface between two media, and when they propagate in a medium, absorption and scattering phenomena are possible waves ... (p. 616, Polytechnic Dictionary "Soviet Encyclopedia", M :, 1989).

There is a known method of producing radiation-shielding concrete according to the patent RU 2545585, published on 10.04.2015 b # 10.

The technical result in this patent is achieved by the fact that in this radio-protective building material obtained from a mixture consisting of Portland cement, sand, mixing water, porous filler and carbon-containing radio-absorbing filler (hereinafter referred to as URN), the porous filler is foam glass granules of size up to 5 mm, and the URN is obtained and used in the form of a structured gel containing 63-51 wt. % 5-10% aqueous solution of polyvinyl alcohol, 4-7 wt. % sodium lignosulfonate, 9-12 wt. % aqueous 25% ammonia solution and 24-30 wt. % of electrically conductive carbon black.

Further, the URN obtained in this way, in order to obtain the actual radio-absorbing material, or building concrete, is introduced into the mixing water of the cement-sand mixture. Moreover, the URN is prepared in advance and has, at the same time, a long shelf life in an airtight container.

The disadvantage of this technical solution is that the specified URN is prepared in advance by a technically complex, energy-consuming method: powdered sodium lignosulfonate is dissolved in an aqueous solution of ammonia, then this solution is mixed with an aqueous solution of polyvinyl alcohol and granular conductive carbon black is dispersed in the resulting solvent, feeding it in portions at the rotation speed of the mixing device is 1400-2000 rpm.

The disadvantage of this technical solution is the unevenness of the mutual distribution of the porous filler and the URN over the volume of the radio-absorbing material, which depends on many subjective factors: the initial viscosity of the solution, the intensity and mixing time of the entire mixture that forms this material, since the porous filler and URN are introduced into the construction mix independently of each other.

The closest analogue of the proposed technical solution, adopted as a prototype, is a method for producing a radioprotective granulate according to the patent RU 2234175 published on November 27, 2003 Bull. No. 33.

Radio-absorbing EMP granulate, mainly for the frequency range 100 MHz - 10 GHz, consists of highly porous glass and (or) ceramic granules coated with ferrite and (or) an electrically conductive material, or which is made by granulating a mixture of glass flour, a blowing agent, ferrite and ( or) an electrically conductive powder with the addition of a binder, followed by drying, thermal hardening and swelling.

According to the description of the process of obtaining such an electromagnetic wave absorbing composite material according to the prototype, the application of an electrically conductive material to the surface of highly porous particles is carried out by spraying a pre-made suspension consisting of this electrically conductive material and a binder solution onto the surface of these highly porous particles in a fluidized bed. The thus obtained composite material, further, to strengthen the binder, is dried at 200 ° C for 16 hours. Therefore, a composite material absorbing electromagnetic waves, or a radio-absorbing granulate, is obtained by performing three sequential steps: obtaining a suspension based on an electrically conductive material and a binder; applying this suspension to the surface of highly porous mineral particles while stirring these particles in a fluidized bed; drying at 200 ° C, for 16 hours, in order to harden the binder.

Thus, the composite material, or granulate, absorbing electromagnetic waves, according to the prototype is complicated and energy-consuming in its manufacture.

The aim of the invention, according to the technical solution described, is to improve the efficiency of the method for producing a composite material that absorbs electromagnetic waves.

The technical results achieved when implementing the method for producing a composite material absorbing electromagnetic waves are:

- increasing the productivity of the process of obtaining a composite material absorbing electromagnetic waves by reducing the mixing time of the mixture;

- reduction of energy consumption when obtaining this composite material due to the elimination of long exposure of the resulting mixture at a temperature of 200 ° C.

The specified technical results in the implementation of the method for producing a composite material absorbing electromagnetic waves is achieved by the fact that in the method for producing a composite material absorbing electromagnetic waves by successive mixing of an electrically conductive material, a binder and an inorganic highly porous filler in accordance with the proposed solution, a mineral sorbent is used as a filler, with a weight with a density of not more than 0.2 g / cm ³ , and the mixing of the mixture is carried out simultaneously at the speed of the stirring device 1300 ÷ 1500 rpm for 35 ÷ 45 minutes, with the content of the mineral sorbent 50 ÷ 82% of the volume, the electrically conductive material 15 ÷ 45% of the volume , binder 3 ÷ 8% of the total volume of the mixture.

Expanded perlite or vermiculite, as well as any other mineral sorbents with a specified density, for example, vermiculite and others, with a weight density of not more than 0.2 g / cm ^3, can be used as a mineral sorbent.

The use of mixing the mixture at a speed of 1300-1500 rpm for 35 minutes to 45 minutes with a mineral sorbent content, with a weight density of not more than 0.2 g / cm ³ , in an amount of 50 ÷ 82% of the volume of the total volume of the mixture, electrically conductive material 15 ÷ 45% of the volume, binder 3 ÷ 8% of the volume, allows you to achieve the following technical results:

- increasing the productivity of the method for producing a composite material absorbing electromagnetic waves by reducing the mixing time of the mixture, as well as by eliminating the need for long exposure, drying, and grinding the resulting mixture, while maintaining the quality of the resulting composite material absorbing electromagnetic waves.

The specified revolutions of 1300-1500 rpm with stirring, provide, in the manufacture of a composite material absorbing electromagnetic waves, the formation of a dynamically stable mixture of a mineral sorbent, an electrically conductive material, a binder and air, in which physical and chemical conditions are created for uniform distribution of a binder, electrically conductive particles over the surface solid particles of the sorbent, which in turn leads to a high rate of mass transfer processes, in this case, the processes of drying the binder, and increases the productivity of the method for producing a composite material absorbing electromagnetic waves, and also reduces energy consumption. (VV Kafarov. Basics of mass transfer, "High school", M 1972, p. 384).

The specified time of this mixing of 1300-1500 rpm, ensures the quality and completeness of the mixing process of the components during the manufacture of the composite material absorbing electromagnetic waves when implementing the method according to the proposed solution.

Optimally, this process takes place at a stirring device speed of 1300 ÷ 1500 rpm. At revolutions less than 1300 rpm, a dynamically stable mixture of a sorbent, a binder, particles of an electrically conductive material and air is not formed, which leads to agglomeration of particles of a composite material and to an increase in their dispersion. At revolutions of more than 1500 rpm, intensive grinding of the sorbent particles is observed, which leads to the loss of a part of the mass as a result of excessive dusting (see Example 3).

Optimally, this process takes place with a mixing time within 35 ÷ 45 minutes. With a mixing time of less than 35 minutes in the internal volume of the mixing device, the drying process of the binder does not have time to complete; in this case, a partially agglomerated mass is observed, with viscous-plastic inhomogeneous particles of the resulting mixture. When stirring for more than 45 minutes, a significant change in the appearance of the particles of the mixture is not observed: further mixing can be considered unreasonable (see Example 1; 2).

Application as a highly porous inorganic filler, for a composite material absorbing electromagnetic waves, a mineral sorbent with a weight density of not more than 0.2 g / cm ³ , with a sorbent content of 50 ÷ 82% of the volume, an electrically conductive material of graphite 15 ÷ 42% of the volume, a binder 3 ÷ 8% of the volume, of the total volume, allows, when implementing the method of obtaining it, to achieve the following results:

- increasing the productivity of the method for producing a composite material absorbing electromagnetic waves by organizing a dynamically stable mixture of a mineral air sorbent by optimizing the ratio of the components included in this composite material absorbing electromagnetic waves so that when the sorbent content is less than 50% of the volume, in the mixture, with a density up to 0.2 g / cm ³ , there is a significant increase in the power of mixing devices to ensure a dynamically stable mixture when obtaining this material, due to an increase in the volume fraction of heavier particles of an electrically conductive material, and when the sorbent content is more than 82% of the volume, insufficient mechanical strength is observed composite material: disintegration of particles of a composite material due to insufficient amount of binder, and mechanical action when mixing this composition with organic and inorganic binders, due to low strength highly porous mineral sorbent (see. Example 1; 2).

The use of an electrically conductive material, graphite, in an amount of less than 15% of the volume, in the implementation of the proposed method to obtain a composite material absorbing electromagnetic waves leads to an increase in the content of a highly porous mineral filler, which causes a decrease in the effectiveness of the proposed method, which manifests itself in the form of dusting (see Example 1; 2).

The use of an electrically conductive material, graphite, more than 42% of the volume, leads to a significant increase in the power of the mixing devices, while ensuring the conditions for creating a dynamically stable mixture, in the process of obtaining this material, since the mass of the charge in the mixer reactor significantly increases (see Example 1; 2 ).

The use of a binder, less than 3% of the total volume, leads to insufficient strength of the resulting material, to the destruction of this material under mechanical action on it during the implementation of the proposed method (see Example 1; 2).

The use of a binder in an amount of more than 8% of the volume leads to excessive, ineffective consumption of this material: the agglomeration of the resulting composite material increases (see Example 1; 2).

The specified value of the sorbent density up to 0.2 g / cm ³ makes it possible to create a dynamically stable mixture of a binder, particles of an electrically conductive material, a sorbent and atmospheric air, with the speed of the stirring device in the range of 1300 ÷ 1500 rpm.

When the density of the sorbent is more than 0.2 g / cm ³ at the speed of the mixing device in the range of 1300 ÷ 1500 rpm, a dynamically stable mixture of the sorbent, binder, particles of electrically conductive material and atmospheric air is not formed, but simple mechanical mixing of the mixture occurs in the bottom layer, without the formation of a sufficient contact surface of the binder with air, which reduces the cure rate of this binder. To obtain the required result, at a sorbent density of more than 0.2 g / cm ³ , an increase in the number of revolutions of the mixing device is required, which is not technically rational, since this significantly increases the power consumption, in addition, a process of excessive intensive destruction of sorbent particles is observed, as a result of destruction its highly porous structure and, as a consequence, an increase in specific gravity. At a sorbent density of less than 0.2 g / cm ³ , a dynamically stable mixture of a sorbent, a binder, particles of an electrically conductive material and air at a selected ratio of components is guaranteed to be formed at a speed of 1300 ÷ 1500 rpm (see Example 1; 2).

In the prototype, with a method for producing a composite material absorbing electromagnetic waves, the effect of a fluidized bed is used, which is a state of granular bulk material, in which, under the influence of a gas flow passing through it, particles of a solid material intensively move relative to each other. The transition of a fixed layer to a boiling one occurs at such a speed of the air flow when the aerodynamic pressure of the flow balances the force of gravity acting on the particles (TSE, vol. 12, "Soviet Encyclopedia", Moscow, 1973, p. 115). Such a technical solution leads to significant consumption of power, since when creating a fluidized bed, a system is required that consists of at least compressor equipment, air supply pipelines, a filter substrate that creates significant resistance to air flow, a system of catching cyclones, which also require energy and mechanical drives for loading and unloading bulk materials.

In the proposed technical solution, the formation of a dynamically stable mixture occurs due to the direct mechanical action of the mixing device on dispersed particles that are part of the composite material absorbing electromagnetic waves.

Example 1

Evaluation of the effect of the mixing time of the mixture, the density of the porous filler and the ratio of the components of the load on the quality of the process of implementing the method according to the proposed technical solution was carried out in laboratory conditions on a special installation.

The installation consisted of a vertically installed mixer reactor, with a volume of 80 liters, with a removable cover, on which an alternating current electric motor with a power of N _dv = 1.0 kW was installed, driving a propeller-type mixer. In addition, the reactor lid is equipped with two necks: one neck is equipped with a lockable lid, the other is docked through a slide gate valve with a sealed cylindrical hopper with a volume of 25 liters.

Mineral sorbents, perlites M 75, M 100, M 200, M 300, M 400 according to GOST 10832-2009 “Expanded perlite sand and crushed stone. Technical conditions ". Graphite "P" in accordance with GOST 8295-73 was used as an electrically conductive material.

The binder used was PVA household glue according to TU 2316-02-45632593-2012, diluted with distilled water to 20% by weight.

The method of obtaining a composite material absorbing electromagnetic waves, according to the proposed solution, on a pilot plant was carried out as follows.

Through an open throat, with a closed gate valve of the other throat, a certain volume of expanded perlite with a known weight density was loaded into the mixer reactor, with the mixer operating at a rotational speed of about 1300-1500 rpm.

Then, after establishing a stable dynamic distribution of the mineral sorbent with the activator operating, under the action of the circulating air mass, uniformly throughout the volume of the reactor, a binder, PVA glue, diluted with distilled water to 20% by weight in an amount corresponding to the recipe, was fed into it through a separating funnel. Graphite, grade "P", was fed simultaneously with the supply of the binder, by gradually opening the gate valve. After continuous stirring of the dynamically stable mixture for a predetermined time, from the beginning of the binder supply, the electric motor was stopped and the composite material thus obtained absorbing electromagnetic waves was manually unloaded from the reactor.

In this case, the quality of the process of implementing the method, according to the proposed technical solution, was assessed by the lack of adhesion of the binder included in this material and by the mechanical strength of the resulting particles.

The lack of adhesion of the binder, which characterizes the completion of the process of obtaining particles of the composite material absorbing electromagnetic waves after stopping the mixing of the mixture, was assessed by pouring 100 ml of the obtained particles from a glass laboratory mill onto a clean sheet of writing paper, followed by holding for at least 5 minutes. In this case, the sample was considered not passed the test if, when the particles were poured from the sheet into the glass, traces of these particles remained at least partially on this sheet: binder stains, or adhered particles. The mechanical strength was assessed by the absence of dusting of graphite or highly porous mineral filler, with mechanical action on the resulting composite material, which was carried out by stirring this material with a hand metal shovel.

The results obtained by mixing in a dynamically stable layer of pearlite with graphite and a binder are shown in Table 1 (see Table 1).

As can be seen from the table, the lack of adhesion of the binder while maintaining the stability of the resulting granules was obtained with a mixing time of 35 minutes to 45 minutes. A mixing time of less than 35 minutes is not enough for a high-quality implementation of the method, since 35 minutes is not enough for reliable mutual adhesion of a highly porous mineral filler and electrically conductive particles due to incomplete drying of the binder.

With a mixing time of more than 45 minutes, mechanical destruction of the resulting particles is observed after the end of the process of adhesion of the highly porous mineral filler and electrically conductive particles.

In addition, it was found that when the weight density of the porous highly porous filler is more than 200 kg / m ³ in the entire range of mixing time, at any ratio of the components in the composition, there is no positive result according to the selected criteria.

The practical results of the work performed showed:

- when the content of the binder is less than 3% of the volume, due to the lack of the binder, the instability of the formed particles is manifested;

- the content of the binder is more than 8% of the volume, there is abundant agglomeration of particles, as a result of an excess of the binder;

- when the content of the highly porous filler in the mixture is less than 50% of the volume, the content of electrically conductive particles increases to values of more than 42% of the volume, which leads to the mixture settling in the bottom layer of the mixer reactor at the selected speed of the mixing device;

- when the content of the highly porous filler in the mixture is more than 82% of the volume, instability of the resulting particles is observed, which characterizes a decrease in the quality of the implementation of the proposed method.

Thus, according to the results shown in Table 1 (see Table 1), taking into account the selected criteria, it can be seen that a positive effect, when implementing the proposed method, was achieved with a mixing time of 35 ÷ 45 minutes, in samples P-6, P- 7, P-8, P-11, P-12, P-13, P-16, P-17, P-18, in which the density of the porous filler is not more than 200 kg / m ³ , the content of the components corresponds to the side-altars: binder 3 -8%, highly porous mineral filler 50-82%, dispersed electrically conductive material 15-42%.

Example 2

According to example 1 (see example 1), an assessment was made of the influence of the mixing time of the mixture, the density of the porous filler, vermiculite, on the quality of the composite material absorbing electromagnetic waves.

In this case, we used vermiculite 100, 150, 200 according to GOST 12865-67 “Expanded vermiculite. Specifications ", graphite of the" GL-1 "grade in accordance with GOST 5279-74 and a binder SDO in accordance with TU13-281078-02-93.

The results are shown in Table 2 (see Table 2)

As can be seen from the table, the lack of adhesion of the binder while maintaining the stability of the resulting granules was obtained with a mixing time of 35 minutes to 45 minutes. A mixing time of less than 35 minutes is not enough for a high-quality implementation of the method, since 35 minutes is not enough for reliable mutual adhesion of a highly porous mineral filler and electrically conductive particles due to incomplete drying of the binder.

With a mixing time of more than 45 minutes, mechanical destruction of the resulting particles is observed after the end of the process of adhesion of the highly porous mineral filler and electrically conductive particles.

In addition, it was found that when the weight density of the porous highly porous filler is more than 200 kg / m ³ in the entire range of mixing time, at any ratio of the components in the composition, there is no positive result according to the selected criteria.

The practical results of the work performed showed:

- when the content of the binder is less than 3% of the volume, due to the lack of the binder, the instability of the formed particles is manifested;

- the content of the binder is more than 8% of the volume, there is abundant agglomeration of particles, as a result of an excess of binder;

- when the content of the highly porous filler in the mixture is less than 50% of the volume, the content of electrically conductive particles increases to values of more than 42% of the volume, which leads to the mixture settling in the bottom layer of the mixer reactor at the selected speed of the mixing device;

- when the content of the highly porous filler in the mixture is more than 82% of the volume, instability of the resulting particles is observed, which characterizes a decrease in the quality of the implementation of the proposed method.

Thus, taking into account the selected criteria, it was determined that a positive effect was achieved with a mixing time of 35 ÷ 45 minutes, in samples B-4, B-5, B-6, B-7, B-8, B-9, B-10 , V-11, P-12, in which the content of the components corresponds to the chapels: binder 3-8%, mineral highly porous filler 50-82%, dispersed electrically conductive material 15-42%.

Example 3

Evaluation of the effect of the rotation frequency of the stirring device on the quality of the implementation of the method for producing a composite material absorbing electromagnetic waves was carried out on the installation according to example 1 (see Example 1), using a frequency converter in the power supply circuit of an electric motor, widespread in Russia and used in the national economy.

Actually, the effect of the device rotation speed on the implementation quality of the proposed method was assessed visually, by the appearance of the resulting product.

Earlier it was shown that the optimal condition for reducing energy consumption, when obtaining a composite material absorbing electromagnetic waves, according to the claimed technical solutions, is the mixing time of the mixtures in the installation corresponding to 35 ÷ 45 minutes. Therefore, the evaluation of the effect of the number of revolutions of the stirring device was carried out at a fixed stirring time equal to 35 minutes, which corresponds to the most unfavorable conditions for obtaining such a material. In this case, the recipes of the reactor charges were used, which led to positive results in examples 1, 2 (see Example 1; 2).

The results obtained are shown in Table 3 (see Table 3).

The table shows:

- when the speed of the mixing device is less than 1300 rpm, the particles form agglomerates, since the mixing intensity is not enough to dry the binder at any of its concentrations;

- when the speed of the mixing device is more than 1500 rpm, the particles are destroyed, which manifests itself in the dusting of the resulting mixture.

Thus, it was found that the particles of the composite material absorbing electromagnetic waves satisfy the previously established requirements at the rotation frequency of the stirring device from 1300 rpm to 1500 (rpm).

Example 4

The radio-absorbing properties obtained according to the proposed technical solution of the composites absorbing electromagnetic waves were evaluated in the composition of the known building mixtures. It is well known that the content of composite materials absorbing electromagnetic waves in the composition of such mixtures corresponds to 60-80% of the volume, of the total volume of the mixture (US 20200317118 A1, 01/30/2020). Therefore, to assess the radio-absorbing properties, samples were used in which the content of particles absorbing electromagnetic waves of the composite material corresponded to 60-80% of the volume, of the total volume of particles absorbing electromagnetic waves of the composite material and the volume of the well-known construction dry mixture.

Moreover, in all cases, the introduction of particles of a composite material absorbing electromagnetic waves into well-known building mixtures was carried out simultaneously with the introduction of mixing water into them. After mixing, the resulting mixtures were distributed in molds with dimensions of 130 × 230 × 20 (mm) and kept in them until curing.

The experimental setup, evaluating the efficiency of absorption of electromagnetic waves, was a vector network analyzer for measuring the S-parameters of four-port networks in the frequency range 0.1-9000 MHz (Cobalt-C1209), equipped with two ports, each of which is connected with the help of coaxial transmission lines. its typical elementary emitter of electromagnetic waves, placed in a typical metal rectangular waveguide, with the dimensions of the ends of 120 × 220 mm. In order to improve the accuracy of measurements, the ends of rectangular waveguides adjacent to the test sample are equipped with frames made of thin textolite, 0.5 mm thick, in size matching the shape and dimensions of the waveguide end.

Evaluation of the effect of a composite material absorbing electromagnetic waves in manufactured samples on the propagation of electromagnetic waves in order to reduce time costs was carried out according to the absorption index in the frequency range from 800 MHz to 1000 MHz, since it is widely known that the lower the frequency of electromagnetic radiation, the more difficult it is to ensure the absorption process. of this radiation. The results obtained are shown in Table 4 (see Table 4).

Thus, even without taking into account the laws of normal distribution of results, it is clear that the composite material absorbing electromagnetic waves in the composition of known mixtures provides protection of premises from the penetration of electromagnetic waves into them.

Example 5

Since the implementation of the method for obtaining samples according to the prototype is based on the technically complex principle of creating a fluidized bed, which requires significant material costs during its implementation, in order to reduce such material costs, a comparison of the effectiveness of methods for obtaining them was carried out theoretically: by comparing the calculated data on the adopted technical solution with calculated data obtained from the description of the prototype patent (see RU 2234175).

The effectiveness of the proposed method for producing a composite material absorbing electromagnetic waves in comparison with the prototype was determined by the formula (1).

Where: F - the value of efficiency in terms of the productivity of obtaining a composite material absorbing electromagnetic waves according to the proposed solution in comparison with the prototype (multiplicity);

G ₁ - the value of the productivity of the method for producing a composite material absorbing electromagnetic waves according to the proposed solution (kg / h);

About ₂ - the value of the productivity of the method for producing a composite material according to the prototype (kg / h).

From table 5, the productivity of the proposed method for producing a composite material absorbing electromagnetic waves is an order of magnitude, 310 times, superior to the method for producing the material, according to the prototype. Therefore, it can be assumed that the cost of obtaining the material by the proposed method is also significantly less in comparison with the prototype.

Example 6

Since the proposed method for producing a composite material absorbing electromagnetic waves allows an order of magnitude to increase productivity, it was decided to isolate the composite material obtained in this way by assigning the name to this material: composite carbon radio-absorbing product (hereinafter ICUR).

It is generally accepted that any proposed method of obtaining a material with the required properties takes place in practice, if the implementation of this method produces a material of the required practical properties.

Therefore, according to example 4 (see Example 4), a comprehensive assessment of the reflection and absorption coefficients of a sample of an electromagnetic wave absorbing composite material obtained on the basis of a cement-sand mixture ChelSI was carried out, in which the IKUR composite material absorbing electromagnetic waves is 70% of the volume, and actually this material consists of pearlite M 200 - 70% (volume), graphite "P" - 25% (volume), PVA binder - 5% (volume).

In accordance with GOST 30381-95 “Electromagnetic compatibility of technical equipment. Electromagnetic absorbers for shielded cameras. General specifications ", the values of the reflection coefficient of electromagnetic waves R were calculated by the formula (2).

Where: VSWR - voltage standing wave ratio (parameter S11)

The results obtained are shown in tables 6, 7 (see Table 6; 7).

As a result, it was found that with an increase in the radiation frequency, the problem of absorption of electromagnetic waves becomes much simpler. Therefore, the use of radio-absorbing materials obtained by mixing standard building mixtures with an electromagnetic wave absorbing composite material IKUR, in accordance with the proposed technical solutions, for the equipment of measuring sites, for the study of side electromagnetic radiation of technical equipment in a wide frequency range, guarantees required technical effect.

Thus, at the measuring site, processed with building material using IKUR, it is possible to conduct laboratory studies of field strengths from 10-15 μV / m (20-23.5 dB μV / m) and above in a wide frequency range from sources of industrial interference and analysis side electromagnetic radiation of technical means of information processing.

The results of the practical work performed show that the method for producing a composite material absorbing electromagnetic waves is effective and allows, with high productivity, to obtain an effective composite material IKUR, which, when mixed by well-known methods with known building materials, provides sufficient protection against electromagnetic radiation.

Claims (1)

A method of obtaining a composite material absorbing electromagnetic waves, carried out by successive mixing of particles of an electrically conductive material, a binder and a highly porous mineral filler, characterized in that a highly porous mineral filler is used with a density of no more than 0.2 g / cm ³ in an amount of 50-82% of the volume, electrically conductive material 15 ÷ 45% of the volume, binder 3 ÷ 8% of the total volume of the mixture, and mixing is carried out at a speed of 1300-1500 rpm for 35-45 minutes.