RU2629016C1 - Compaund with blocking vitreous surface layer and dense diffusion near-surface layer for immobilizing toxic, radioactive, household and industrial wastes and method of its production - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: compound with a blocking vitreous surface layer and a dense diffusion near-surface layer includes magnesite caustic powder (PMC), magnesium chloride solution, catalytic carbonaceous additive and waste or fillers for building compounds. In the solution of magnesium chloride for an amount of 200 to 400 g/l, a solution of iron sulfate with the density of 1.08-1.10 g/cm³ in the amount of 0.1-0.4 of the weight of the resulting magnesium chloride solution, 10-20% solution of copper sulfate with the density of 1.08-1.10 g/cm³ in the amount of 0.04-0.13 of the weight of the magnesium chloride solution produced, the magnesite caustic powder and the catalytic carbon-containing additive.

EFFECT: it is allowed to obtain a vitreous surface layer, which excludes the ingress of radionuclides and toxins into the environment.

5 cl, 4 dwg, 1 tbl

Description

The invention relates to the field of atomic engineering and technology, relates to the processing of low and medium level radioactive waste, construction, utilization of industrial and household waste, the disposal of radioactive waste, the production of containers for storage and transportation of radioactive waste.

A composition is known for the formation of a solid solid monolithic block, fixing in its structure the components of liquid radioactive waste, based on a magnesian binder, including a solution of a three-component hardener, consisting of a mixing liquid in the form of a solution of magnesium chloride with a density of 1.2-1.35 g / cm3, magnesian astringent and finely divided mineral filler with a particle size of 0.005-0.015 mm In this case, a solution of bischofite is used as a solution of magnesium chloride, and a mixture of metallurgical waste containing magnesium oxide and silicate with a specific surface area of 3.0-7.0 m ² / g and brucite dust is used as a magnesia binder. Moreover, as a finely divided mineral filler, barite powder (feldspar) is used (US Pat. RF No. 2214011).

However, the composition for obtaining the immobilizing material - compound, described in the known method according to the patent of the Russian Federation No. 2214011, has several disadvantages. Thus, the process of curing the immobilizing waste material takes a rather long time, so much so that radioactive waste with a low specific gravity has time to float in the immobilizing solution during this time, and as a result, in the resulting compound, the degree of its filling with waste throughout the volume becomes uneven. The use of barite or feldspar powders as a filler narrows the scope of this composition, restricting its use for immobilizing only liquid radioactive waste and does not allow for the distribution of solid radioactive and chemical toxic wastes, such as, for example, ash from waste incineration , slags from the remelting of radioactively contaminated metals, etc., since in this case, the formation strength sufficient for long-term storage is not provided shegosya monolithic block comprising said waste. Thus, in this composition, the material for immobilizing liquid radioactive waste, including curing the latter in it and holding until a solid solid monolithic block is formed, is not cost-effective and universal and has a limited raw material base.

Known composite material for the immobilization of liquid radioactive waste according to RF patent No. 2483375, including a hardener, caustic magnesite powder and a catalytic carbon-containing additive, characterized in that solid salts are used as a hardener, and solutions of potassium ferrocyanide and nickel nitrate, as well as calcium chloride, are additionally introduced. in the following ratio, wt. %:

A significant drawback of this analogue is the absence of a blocking surface or near-surface layer on the material, which provides real immobilization of liquid radioactive waste. The absence of a locking surface or surface layer leads to the penetration of radionuclides into the environment.

A known method of immobilization of radionuclides of alkaline earth and rare earth elements in a mineral matrix (patent RU 2444800). A method of immobilizing alkaline earth and rare earth element radionuclides in a mineral matrix based on metasomatic substitution reactions in “wet” conditions involves passing a nitrate solution of said radionuclides through a column filled with mineral particles with sizes in the range of 0.4-0.63 mm of a model granite mixture or natural granite with crystalline anhydrous sodium orthophosphate, with a mass ratio of sodium orthophosphate to the mixture equal to 1: 3-4; dehydration of the contents of the column by heating from room temperature to 400 ° C; impregnation of the contents of the column with liquid sodium silicate with a silicate module equal to 2; subsequent annealing of the obtained mineral composition at a temperature of 900-1250 ° C and atmospheric pressure, or hot pressing at a temperature of 815-900 ° C and an axial pressure of not higher than 700 kg / cm ² to obtain a crystalline mineral matrix containing radionuclide phosphate.

The disadvantage of this invention is the high energy consumption - to obtain the temperatures specified in the method requires significant energy costs, and, accordingly, financial costs. In addition, passing a solution of radionuclide nitrate through a column seems to be an unnecessary complication of the technology. The principal difference of our invention from this method is the use of only mixing various components without external thermal effects on the mixture.

A known method of localization of radioactive contamination (patent RU 2586072 ⁽¹³⁾ C1). The invention relates to a method for localizing radioactive contaminants, for example, in a radioactive waste burial zone (RW), and can be used to purify groundwater from radioactive radium-226 dissolved in them. The method provides for setting up a geochemical barrier of solid filler, iron oxide and working components on the migration paths of radioactive groundwater, upon dissolution of which sulfate ion and barium cation are released. In this case, radium 226 is fixed in the crystal lattice of the resulting radio barite. Gypsum is used as the substance containing the sulfate ion, and Witerite is used as the substance containing the barium cation. Goeth / hematite is used as iron oxides, crushed stone is used as filler - granite, diorite, dunite, or diabase. The disadvantage of this invention for the immobilization of radioactive waste (RW), including liquid radioactive waste (LRW) is the narrow scope, namely ground water containing radium 226. Our invention is applicable to all types of radioactive waste (RW), in this is the advantage and difference of our method.

A known method of solidification of radioactive waste (RAW) and other hazardous waste (patent RU 2416832). The method of solidification of radioactive waste (RW) and other hazardous waste includes heating, saturation with a solution to achieve the desired degree of filling, binding and fixing of radionuclides or other hazardous waste inside the unit. The block is made of crystalline hydrates of artificial mineral salts by pouring a crystalline hydrate melt into a mold with liquid waste previously placed in it. The melt is cooled to form solid crystalline hydrates to form a solid block. The disadvantage of this invention is the instability of the block to thermal effects. When the block is heated, it passes into the melt with the subsequent release of radionuclides into the environment. In our invention, radionuclides are securely locked in a closed compound protected by low permeable to radionuclides surface and glassy near-surface layers. The second disadvantage of this invention is the need for special heating of the material, which naturally increases its energy and economic value. In our invention, an exothermic reaction occurs, as a result of which a strong compound with insulating surface and near-surface layers is formed.

A device for the immobilization of liquid radioactive waste (RU 93571 U). The utility model relates to the field of nuclear engineering and technology, concerns the processing of liquid radioactive waste using inexpensive natural materials. This is achieved by the fact that in a device for immobilizing liquid radioactive waste containing a monolithic block, including concentrated liquid radioactive waste and a liquid hardener, fixing the components of radioactive waste (RAO) in its structure, according to a useful model, the hardener is made in the form of a solution of a three-component hardener, consisting of a solution of magnesium chloride, a magnesian binder and a finely divided mineral filler, and the monolithic block is equipped with a container in which it is enclosed, the walls of which are made of the inside is covered with polystyrene, and the container is equipped with load gripping devices. The disadvantage of this invention is the absence of a low permeable near-surface and glassy surface layer on the monolithic block, which leads to insufficient isolation of radionuclides from the environment. In our invention, a glassy surface and diffusion surface layers are formed, which provide complete isolation of the radionuclides from the environment.

Known (prototype) composite material (closest in composition to the proposed invention) for immobilizing radioactive and chemical toxic wastes based on magnesia binder according to patent RU 2378723 from 04/10/2010, including a hardener solution consisting of a mixing fluid, magnesia binder and filler, characterized in that it hardener solution as mixing fluid includes an aqueous solution of magnesium sulfate density of 1.1-1.3 g / cm ^3, and the magnesia binder is included in powder magnesite kaust iCal, wherein the composite material further comprises a catalytic carbonaceous additive in the following ratio, wt. %:

caustic magnesite powder 30-50 filler 30-50 catalytic carbon additive 0.01-0.5 aqueous solution of magnesium sulfate rest

The disadvantage of this composite material is the excess of one of the main, according to GOST R 51883-2002, quality indicators of cement compounds, namely, the leaching rate for cesium-137 (≤1⋅10 ^-3 g / cm ² ⋅ days) - even with a small degree filling (3-8 wt.%) of compounds with radioactive salts. This is due to the fact that the matrix of magnesia cement (MC) is not a barrier to cesium-137, and the effectiveness of the sorbents introduced into the composite material to retain radionuclides with the required parameters is not enough. Another disadvantage of the prototype is the lack of resistance of the composite material to a long stay in water. A significant disadvantage of the prototype is also the absence of a locking surface or near-surface layer on the material, providing real immobilization of liquid radioactive waste.

The objective of the invention is the creation of a locking glassy surface and dense diffusion surface layer on the composite material, increasing the resistance of the composite material to prolonged residence in water.

The technical result consists in the possibility of obtaining a vitreous surface layer, eliminating the ingress of radionuclides and toxins into the environment, a dense immobilizing diffusion surface layer (up to 15 mm thick), which increases the strength and water resistance of the material, increasing the resistance of the composite material to prolonged exposure to water.

The specified technical result is achieved due to the fact that the claimed composition with a locking vitreous surface layer and a dense diffusion surface layer, including caustic magnesite powder (PMC), magnesium chloride solution, a catalytic carbon-containing additive and waste or fillers for building compounds, characterized in that composition solution of magnesium chloride in an amount of from 200 to 400 g / l are used: ferrous sulfate solution density of 1,08-1,10 g / cm ³ in an amount of 0.1-0.4 mass obtained p alignment magnesium chloride, 10-20-year-percent solution of copper sulfate density of 1,08-1,10 g / cm ³ in an amount of 0,04-0,13 mass obtained from the magnesium chloride solution and caustic magnesite powder catalytic carbonaceous additive.

Also claimed is a method of obtaining the above compound, which is characterized in that in order to obtain a glassy surface layer and a dense surface layer, bischofite is additionally introduced into a magnesium chloride solution in an amount of 200 to 400 g / l, an iron sulfate solution with a density of 1.08-1, 10 g / cm ³ in an amount of 0.1-0.4 by weight of the resulting solution of magnesium chloride, 10-20 percent solution of copper sulfate with a density of 1.08-1.10 g / cm ³ in an amount of 0.04-0, 13 by weight of the resulting solution of magnesium chloride, mix the resulting combination a bath solution with caustic magnesite powder and a catalytic carbon-containing additive, the resulting mixture is kept for 2-8 minutes, then mixed with waste or filler, then the resulting mixture is mixed with a 9-11% sodium phosphate solution with a density of 1.05-1.07 g / cm ³ ; the mixture obtained after mixing is placed in the final form, depending on the heat capacity of the filler, dimensions, the inner surface of which is coated with a polymer.

Preferably, the inner surface of the mold is coated with polystyrene or polyvinyl chloride.

Preferably, the inner surface of the mold is coated with polyethylene terephthalate.

Preferably, the inner surface of the mold is coated with polypropylene.

The invention is illustrated by drawings:

In FIG. 1 shows the process of ion attachment to a simple particle.

In FIG. 2 shows the structure of the colloidal micelle, where 1 is the core, 2 is the adsorption layer of counterions, 3 is the diffusion layer of counterions.

In FIG. Figure 3 shows a photo of the compound at different ratios of vitriol solutions.

In FIG. 4 shows a compound destroyed after 60 days of hardening.

The implementation of the invention

The present invention differs from the prototype both in the composition of the initial mixture and in the method of obtaining the material - and in the sequence of operations: bischofite is additionally added to the magnesium chloride solution in an amount of 200 to 400 g / l, iron sulfate solution with a density of 1.08-1.10 g cm ³ in an amount of 0.1-0.4 by weight of the resulting solution of magnesium chloride, 10-20 percent solution of copper sulfate with a density of 1.08-1.10 g / cm ³ in an amount of 0.04-0.13 by weight the resulting solution of magnesium chloride, mix the resulting combined solution with powder magnesite caustic and catalytic carbon-containing additive, the resulting mixture is kept for 2-8 minutes, then mixed with waste or filler, then the resulting mixture is mixed with a 9-11% sodium phosphate solution with a density of 1.05-1.07 g / cm ³ , the mixture obtained after mixing is placed in the final form, depending on the heat capacity of the filler, dimensions, the inner surface of which is covered with polystyrene (for example, adhesive tape).

The result of the invention is to obtain a vitreous surface layer, eliminating the ingress of radionuclides and toxins to the environment. This result is achieved by introducing an additional amount of bischofite in an amount of 200 to 400 g / l, as well as placing the resulting suspension in a shell that is impermeable to ions of the suspension, as a result of which, during the exothermic hardening reaction, the flow of light magnesium and chlorine ions moving from the most heated section to the center of the form to the boundaries of the form, where an insurmountable barrier is encountered, form a heated supersaturated bischofite solution and, when cooled sharply, form a thin layer of glass. The vitreous layer is obtained as a result of supercooling of a saturated aqueous solution of salts, which occurs due to the temperature difference between the center of the form and its boundaries during the exothermic reaction, as well as an excess of mixing liquid.

The vitreous inorganic salt layer is a solid, amorphous material that is obtained after supercooling a heated, saturated solution of electrolyte salts. The result - obtaining a dense immobilizing diffusion surface layer (up to 15 mm thick), increasing the strength and water resistance of the material, is achieved by introducing an additional amount of bischofite and iron sulfate solution with a density of 1.08-1.10 g / cm ³ in an amount of 0.1- 0.4 by weight of the resulting solution of magnesium chloride, 10-20 percent solution of copper sulfate with a density of 1.08-1.10 g / cm ³ in an amount of 0.04-0.13 of the mass of the resulting solution of magnesium chloride. The ions of these solutions during the exothermal hardening reaction, moving from the most heated section in the center of the mold to the boundaries of the mold where an insurmountable barrier — the glassy surface layer — meet, form a dense diffusion layer, characterized by strength and water resistance.

The result is an increase in the resistance of the composite material to prolonged residence in water, which ensures mixing of the mixture with a 9-11% solution of sodium phosphate with a density of 1.05-1.07 g / cm ³ . As a result, a material is formed containing insoluble magnesium phosphate salt.

The significance of the differences is proved by many years of theoretical and experimental research.

A compound with a locking vitreous surface layer and a dense diffusion surface layer for immobilizing toxic, radioactive, domestic and industrial waste is a material that forms a special high-strength surface layer due to the mass and energy of the initial suspension.

The process of formation of this material is carried out by the interaction of hydrated MgO particles with solution ions and heat release during exothermic reactions of hydration of MgO and the formation of magnesium trioxochlorides (in the amount of 926 kJ / kg).

In the case of using fullerene-containing additives and solution-impermeable walls of the material form walls, a potential difference is formed between the center of the volume of the compound and the interface between the suspension and the form. The result is a high-strength, low-permeable, dense, near-surface compound layer and a vitreous, low-permeable, surface compound layer. The hardening of the compound in air is unacceptable.

Caustic magnesium powder, hereinafter PMC, is a polyphase substance capable of hydration in the presence of magnesium salts (chloride, sulfate) and the creation of a stone with specific properties.

The simplest particle of the binder - PMC is a dust micelle caught by electrostatic precipitators and flying into the atmosphere during the remelting of magnesite to periclase. This particle (in the case of the correct firing regime) has a developed surface. It contains: α-form MgO, MgCO ₃ , β-form MgO-periclase and a small amount of carbon. If a particle enters a solution of magnesium chloride MgCl ₂ ⋅ 6H ₂ O (bischofite) or MgSO ₄ , its hydration occurs - part of its surface becomes charged. The ionic capacity of a particle is the maximum possible number of ions capable of attaching to a given particle. The ability of a particle to hydrate and combine with other simplest particles is characterized by its binding. The connectivity of the simplest particle — the relative rate of consumption by the particle of the ions of the surrounding solution — the relative rate of formation of the charged surface of the simplest particle. This speed should be related to the number of bischofite solution ions falling on the simplest particle С _p ⋅ С _{p is} rigidly determined by the density of bischofite solution and the ratio W: T (the ratio of the masses of the solution and the binder) with a known number of particles per unit mass of PMC.

Bondability s is the rate of attachment of ions of a solution of MgCl ₂ (or MgSO ₄ ) to the simplest (30–40 nm) PMA particle is expressed in both quantitative and mass form. The rate of change in the concentration of ions in an elementary volume around a particle is proportional to the connectivity s of the simplest particle and the current concentration C of ions in solution

Solving this equation (1), we obtain the dependence for the concentration of ions on the simplest particle C _h (taking the initial concentration of ions as 1)

That is, over time, all the ions falling on the particle will be consumed by it. This would be so if the ionic capacity of the particle was greater than the number of solution ions falling on the simplest particle C _p . In normal modes, this is not observed. The process of attaching ions to the simplest particle is similar to the process of charging a capacitor (see Fig. 1), where C ₀ is the ionic capacity of the particles.

As a result of the described process, the surface of a simple particle acquires a charge distributed over those parts of the surface where α-form MgO molecules are located. A charge distributed over those parts of the surface where β-form MgO molecules are located can occur in a time exceeding the compound formation time and lead to a loss of stone strength.

Schematically, the micelle of a sol of magnesium oxide obtained in excess of magnesium chloride (potential-determining ions - Cl ^- anions, counterions - Mg ⁺ ions) can be depicted as follows:

In FIG. 2 shows the structure of colloidal micelles. The simplest particles are distributed according to their connectivity and this distribution is described by the distribution function. In general, a magnesian binder is described by the distribution function for connectivity, however, a specific batch of PMC can be described by one weighted average connectivity. We have established a strict relationship between the binding of PMC and the temperature of the exothermic hardening reaction, the total heat release of the exothermic hardening reaction of a mixture of this PMC with a bischofite solution. With the same parameters of the mixture — liquid to solid ratios, bischofite solution density — the higher the PMC binding, the higher the temperature of the exothermic curing reaction and the total heat release of the exothermic curing reaction of the mixture of this PMC with bischofite solution.

We found that the higher the density of the bischofite solution, the higher the temperature of the exothermal hardening reaction and the total heat release of the exothermal hardening reaction of the mixture of this PMC with the bischofite solution. In addition, it was found that the addition of copper and iron sulphate solutions to the mixing fluid allows one to control the course of the exothermic hardening reaction of a mixture of this PMC with a bischofite solution: the higher the proportion of copper sulphate solution relative to the iron sulfate solution, the higher the temperature of the exothermic hardening reaction and the total heat release of the exothermic hardening reaction mixtures of this PMC with bischofite solution. Thus, it is possible to compensate for the low connectivity of this PMC by adding copper and iron sulphate solutions to the mixing liquid, due to which the temperature of the exothermic hardening reaction and the total heat release of the exothermic hardening reaction of the mixture will be maintained. This makes it possible to ensure intense ion-exchange reactions with the formation of sparingly soluble salts - magnesium sulfate and iron and copper chlorides, to support the movement of ions from the center of the mixture form to its boundaries with the formation of an immobilizing diffusion surface layer, which increases the strength and water resistance of the material and a vitreous surface layer, eliminating the ingress of radionuclides and toxins environment.

The hardening process is accompanied by an increase in the viscosity of the mixture. We have established a strict relationship between the ratio of the components of the mixing fluid — bischofite solutions, copper and iron sulfate — and the viscosity of the mixture at the moment of hardening (with a constant ratio of liquid to solid). Using this relationship, we are striving to ensure the uniform distribution of waste and fillers of various densities in terms of the volume of the resulting stone.

It is necessary to ensure water resistance of the stone. Since the temperature of the exothermic hardening reaction and the total heat release of the exothermic hardening reaction of the mixture are maintained, we can provide intense ion-exchange reactions with the formation of insoluble salts, in particular magnesium phosphate. To this end, we add the operation of mixing the resulting mixture with a 9-11 sodium phosphate solution with a density of 1.05-1.07 g / cm resulting in the formation of insoluble magnesium phosphate and sodium chloride. So they achieve an increase in water resistance and a decrease in the leachability of the resulting stone.

All the processes described above are provided by the energy of the exothermic reaction of the hardening of the mixture. Consider the laws of formation of our compound.

The fundamental task of the above study of the process of formation of our material carries a prediction of the function of the state of the compound.

In the case when the ionic density of the solution — the number of ions in the solution of one simple particle — exceeds the ionic capacity of the particles, and the average PMC connectivity is quite high, it is more convenient to use the distribution function over the total surface charge q.

State function

In order to predict the processes occurring in the COMPOUND and determine the results of these processes, the concept of the state function of the compound γ (q, x, y, z, t, ν) is introduced, which describes the state of a particle with charge q at time t, at the point x, y , z. In the case when the ionic density of the solution — the number of ions in the solution of one simple particle — exceeds the ionic capacity of the particles, and the average PMC connectivity is quite high, it is more convenient to use the distribution function over the total surface charge.

зависящей от заряда q, x, y, z, tIn the field of electrostatic action of the simplest particles, ions move with a speed averaged for each ion

charge dependent q, x, y, z, t

where i, j, k are the unit vectors of all coordinates x, y, z. Here, the velocity vector is decomposed into components along the coordinate axes. The average speed is such a speed from which a random component is excluded.

для фиксированного q=const во всех точках зоны определяет поле скоростей в зоне элементарной фракции (q, q+dq).Vector function

for a fixed q = const at all points of the zone determines the velocity field in the zone of the elementary fraction (q, q + dq).

является важнейшим промежуточным шагом к решению фундаментальной задачи предсказания: по известной функции

однозначно и строго вычисляется искомая функция состояния γ(q, x, y, z, t) из закона сохранения, который рассматривается ниже.Finding a velocity field

is the most important intermediate step to solving the fundamental prediction problem: by a known function

the required state function γ (q, x, y, z, t) is uniquely and strictly calculated from the conservation law, which is considered below.

Local, i.e. the conservation law valid for a neighborhood of any local point x, y, z and any elementary fraction

where m = m (q, x, y, z, t); γ = γ (q, x, y, z, t) and

W (q, x, y, z, t) conducted (diverted) flow

зависящей от x, y, z, t (здесь

или

) является скалярная функцияRecall that the divergence of any vector function

depending on x, y, z, t (here

or

) is a scalar function

на оси x, y, z;where Ax, Ay, Az are projections

on the x, y, z axis;

V is the local volume;

s is the bounding surface around x, y, z.

For m = const and W = 0, equation (2) can be written as

To predict the state function, the local conservation law is not enough, since it gives only one equation with 2 unknowns.

Let's take as the second equation - the balance equation of statistically averaged forces acting on particles of any elementary fraction

those. the sum of the forces acting on the particle is zero.

Gravitational force referred to unit density particle ρ

Archimedean force for a medium with density ρ _cf

Stokes force

where I is the hydraulic particle size,

ν is the particle velocity,

ν _cp is the velocity of the medium.

α is the drag coefficient proportional to the viscosity of the medium

Gradient force

where k is the coefficient of proportionality,

for m ≠ const we have

с точки зрения кинетической теории имеемBy revising

from the point of view of kinetic theory, we have

- средний квадрат скорости движения частиц.Where

- the average square of the particle velocity.

Coulomb Power

where E is the field strength.

Let perfect mixing of solid in suspension. This eliminates the dependence of the process on the coordinates of the space x, y, z. The conservation law then looks like this:

where S is the specific surface of the particle reduced to the surface of the sphere,

γ = γ (ν, t) is the differential distribution over the binding of particles of PMC,

ν is the rate of attachment of the ion to the PMC particle (hydration rate) and connectivity.

In our case, the material formation process is affected by two distribution functions of the simplest PMC particles with respect to s connectivity s and the charge distribution function of suspension ions q. The movement of ions to and from the particle is described in a manner standard for electrokinetic phenomena; The basis of the description of electrokinetic phenomena is the theory of the double electric layer (DEL).

Consider the real situation in suspension. Under the constrained conditions of a real suspension, the action of the Coulomb forces leads to the chaotic motion of ions and particles. If the densities of the particle and the medium are close, the interaction of gravitational and Archimedean forces can be neglected. The most important here is the interaction of gradient forces and resistance forces.

The emergence of gradient forces in our case begins from the moment of hydration of the simplest particle and the first stage of heat generation associated with this process. The thermal movement of ions and simple particles begins. This movement is the more intense, the more the simplest particle of neighbors transferring their energy to it. Thus, the point in the geometric center of the form becomes the hottest. The most “cold” are the points at the borders of the suspension with the outer shell - the form. Particles with greater energy and momentum begin to actively move from the center of the form to its boundaries, transfer part of their momentum to other, less “energetic" particles located further from the center, etc. Let's move on to the forces of resistance to movement.

They can be attributed to two types: the resistance of the medium and the resistance of the surrounding particles of PMC and ions. The resistance of a homogeneous medium can be taken into account by traditional deterministic methods. Therefore, we will deal with the resistance force arising from collisions, for this we assume that the medium is absent. Select one particle of the elementary fraction and imagine that it has a gradient force

The particle will begin to accelerate with constant acceleration, but after passing some path, it will hit another PMC particle and lose part of the speed, etc., then at the next impact it will again lose the accumulated directional speed (the chaotic component of the velocity y will remain). After impact, the particle will again begin to accelerate directionally. Then, at the next impact, it will lose directional speed gained, etc. Under these decelerations, the particle loses part of its momentum, transmitting this part of the momentum to other particles.

частицы в единицу времени (изменение импульса, которое передается окружающим ее частицам при соударениях), т.е. эта сила равнаThe average braking force is equal to the loss of momentum

particles per unit time (the change in momentum that is transmitted to the particles surrounding it during collisions), i.e. this force is equal

where m _part is the mass of the particle.

Тогда потеря количества движений за одно столкновение равна

, а за единицу времениIt can be calculated approximately as follows: let the average particle travel time between collisions be equal to τ, and during each collision it completely loses directional velocity

Then the loss of motion in one collision is

per unit time

α _part - proportionality coefficient (when moving from an individual particle to a unit volume, we replace α _part by α.

In unrestricted conditions, when the particles do not collide with each other, the gradient force and the resistance force disappear (the resistance of the medium remains).

и

, то частицы ведут себя в зоне разделения между центром и стенками формы как при (свободной) диффузии.Consider the diffusion effects of the combined action of the forces of gradient and resistance. Gradient force arises due to the temperature difference between the geometric center of the form and its boundaries. If the particles of the elementary fraction [ν, ν + dν], only two forces act

and

, then the particles behave in the separation zone between the center and the walls of the form as in (free) diffusion.

To prove this, we take the two initial equations as the local conservation law for m = const and the balance of forces.

с помощью подстановки, получим уравнение диффузии для функции состоянияExcluding

using substitution, we obtain the diffusion equation for the state function

where the macrodiffusion coefficient D = kα ^-1 , m ² / s, is introduced.

Denote the concentration of the elementary ith fraction by C _i , then the equation takes the form

Here, for a fixed s, the equation predicting C _i is the diffusion equation (such as the heat equation). The solution to this classical equation by mathematical physics (introduced by Fourier) is well-established. In particular, the one-dimensional solution of the Cauchy prediction problem: find C _i (x, t ₀ ) for t> 0 from a given initial C _i (x, t ₀ ) for t ₀ = 0 for unlimited space has the form:

where λ is an intermediate variable that disappears after substituting the limits of integration.

и F_сопр на примере продвижения частиц элементарной фракции связуемости ν от центра к границе формы.We will use this solution to illustrate the physical meaning of the forces in question.

and F _sopr on the example of the movement of particles of the elementary cohesion fraction ν from the center to the boundary of the form.

We take the space x horizontal and, to fall within the framework of the mentioned Cauchy problem, we take it infinite. Time t is counted from the moment t ₀ = 0 the beginning of the exothermic reaction.

We load the mentioned elementary fraction exactly in the center of the form at the point x = 0. therefore, the initial condition of the Cauchy problem has the following particular form

where C ₀ = const is the given concentration of the considered fraction (ν _i , ν _i + dν) at the point x = 0 at t = 0; δ (x) is the momentum function.

Substituting this initial condition into the general solution and performing integration, we obtain the desired function C _i (x, t) for t> 0

среднее квадратическое отклонение в полученном нормальном законе распределения фракций (γ, γ+dγ) по горизонтальному пространству зоны.Where

standard deviation in the obtained normal law of the distribution of fractions (γ, γ + dγ) over the horizontal space of the zone.

, при t₂>t₁ рассеивание становится еще больше и

становится еще большим.At t ₀ = 0, all particles are concentrated in the center of the form (x = 0); at t ₁ > t _{0, the} initial momentum is considered in the normal distribution with

, at t ₂ > t _{1 the} dispersion becomes even greater and

getting bigger.

At D = 0, which corresponds to the absence of a gradient force or an infinitely large resistance force, all considered are in the center of the form.

Note that from the well-known C _i (x, t) equation ∑F _i = 0, we can find ν _i (x, t) in the example under consideration, the equation ∑F _i = 0 takes the form

where, taking into account the equation, one can find the velocity field of the fractions under consideration

The emergence of gradient forces in our case begins from the moment of hydration of the simplest particle and the first stage of heat generation associated with this process.

The thermal movement of ions and simple particles begins. This movement is the more intense, the more the simplest particle of neighbors transferring their energy to it. Thus, the point in the geometric center of the form becomes the hottest. The most “cold” are the points at the borders of the suspension with the outer shell - the form.

Particles with greater energy and momentum begin active movement in the center of the form, transfer part of their momentum to other, less "energetic" particles located further from the center, etc.

The process leads to the formation of a layer of positively charged protozoa particles at the suspension - polystyrene boundary. The charge is distributed at different points on the surface of a simple particle. The number of such charges is determined by the binding of the particle and is limited by its ionic capacity.

The temperature difference between the center of the form and its boundaries leads to the movement of ions - ionic currents arise.

After the initial formation of stone - the occurrence of hydroxyl-chloride bonds between the simplest particles - i.e. acquiring a solid compound, the process of its transformation begins, accompanied by a powerful thermal effect. This powerful heat release (922 kJ / kg) leads to a powerful cumulative momentum of ion motion, which, as a result of many collisions, forms a layer of negatively charged ions at the compound-form interface.

As a result, a glassy surface layer is formed, which excludes the ingress of radionuclides and toxins to the environment, a dense immobilizing diffusion surface layer that increases the strength and water resistance of the material.

The formation of a dense immobilizing diffusive surface layer occurs due to the action of the gradient forces described above, the energy, and the mass of “fast” ions of the mixture, which have encountered an insurmountable barrier in the form of a glassy surface layer. In the photo of FIG. 4 shows a fracture of a compound destroyed after 60 days of hardening. It is easy to see that the color of the dense immobilizing diffusion surface layer differs from the color of the internal volume of the compound. The value - thickness - of the surface layer was 15 mm.

In the photo of FIG. 3 shows the compound after 7 days of hardening. A vitreous inorganic salt layer covers the surface of the material, virtually eliminating the ingress of radionuclides and toxins to the environment.

The vitreous layer is obtained as a result of supercooling of a saturated aqueous solution of salts, which occurs due to the temperature difference between the center of the form and its boundaries during the exothermic reaction, as well as an excess of mixing liquid. The excess mixing liquid and / or ions of electrolyte salts is the difference between the concentration of the introduced mixing liquid and the concentration required by the stoichiometric ratio. The vitreous inorganic salt layer (sns layer) is a solid, amorphous material, which is obtained after supercooling a heated, saturated solution of electrolyte salts. This vitreous inorganic salt layer has the mechanical properties of a solid and is characterized by thermodynamics and metastability, not transparent to toxins and radioactive isotopes. It differs from crystals and liquids in its structure. The vitreous inorganic salt layer of X-ray is amorphous due to disordered atomic structure. Its structure lacks long-range order, it is isotropic, does not have a specific melting and solidification temperature.

In our case, the melt passes from a liquid to a plastic state, and then to a solid state, which is a vitrification process. The vitreous inorganic salt layer is transparent in various spectral regions. The density of the vitreous inorganic salt layer ranges from 2.2 to 8 g / cm ³ .

Inorganic salt glass is a strong but brittle material and is very sensitive to shock. With low-temperature ion exchange, it is possible to achieve hardening of our glass by replacing ions of some alkali metals with ions of others of a larger radius. After which there is a compressed surface layer of much higher density. The thickness of the surface layer in our case can reach 20-40 microns (micrometers). The structure of the glass corresponds to the structure of the liquid in the glass transition interval.

The geometry of the mutual arrangement of the vitreous inorganic salt layer corresponds to the geometry of those ions that have reached the glass transition boundary. Thus, by changing the glass transition point, i.e. temperature, by external cooling or heating, we can provide the desired structure of the vitreous inorganic salt layer.

The formation of the primary link of the crystallization center leads to the appearance of an interface between the crystalline and liquid phases, which entails an increase in the free energy of the system, which at temperatures below the liquidus temperature (those corresponding to the liquid state is thermodynamically less stable than crystalline, otherwise metastable) energy, less than free energy of a liquid of the same mass. A decrease in the size of the body, the ratio of its surface to volume increases, the smaller radius of the center of crystallization corresponds to an increase in free energy associated with the appearance of a phase separation.

Any liquid in a metastable state is characterized by a critical radius of the center of crystallization, less than which the free energy of a certain volume of a substance, including this cent, is higher than the free energy of a volume of the same substance, but without a center. For a radius equal to critical, these energies are equal, and for a radius greater than critical, further growth is thermodynamically regular.

With decreasing temperature, the number of subcritical centers increases, which is accompanied by an increase in their average radius. In addition to the thermodynamic, the kinetic factor influences the rate of formation of centers - the freedom of movement of particles relative to each other determines the speed and growth of crystals. Thus, increasing the ratio of liquid and solid phases in the direction of the predominance of liquid, we increase the freedom of movement of ions. With the same amount, we increase the rate of formation and crystal growth.

In the photo of FIG. Figure 3 shows two variants of the glassy surface layer - the color of the stone depends on the color of the surface layer, i.e. the ratio of vitriol solutions.

In the photo of FIG. 4, where the destroyed material is shown, a dense diffusion surface layer up to 12 mm thick is clearly visible.

The material of the inner surface of the mold to accommodate the resulting mixture, impermeable to ions of the mixture is polystyrene, polyvinyl chloride, polyethylene terephthalate, polypropylene or silicone. Provides the formation of a surface layer that prevents the ingress of radionuclides and toxins to the environment, a dense immobilizing diffusion surface layer that increases the strength and water resistance of the material.

Examples and tests of strength.

Samples of a cubic shape with a rib of 100 mm were obtained as a result of operations carried out in accordance with the invention. As fillers used: ash burning sludge sediment vodokanal, metallurgical slag and granite chips. The results of determining the compressive strength are shown in table 1.

The addition of a 10% solution of technical trisodium phosphate is 2.7% of the total sample weight. Changes in the mass and strength of the samples after prolonged exposure to water for up to 60 days did not exceed 2.1%.

Claims (5)

1. A compound with a locking vitreous surface layer and a dense diffusion surface layer, including caustic magnesite powder (PMC), magnesium chloride solution, a catalytic carbon-containing additive and waste or fillers for building compounds, characterized in that the composition of the magnesium chloride solution contains from 200 up to 400 g / l used: a solution of iron sulfate with a density of 1.08-1.10 g / cm ³ in an amount of 0.1-0.4 of the mass of the resulting solution of magnesium chloride, 10-20 percent solution of copper sulfate pl the ratio of 1.08-1.10 g / cm ³ in an amount of 0.04-0.13 of the mass of the obtained solution of magnesium chloride, caustic magnesite powder and a catalytic carbon-containing additive. 2. The method of obtaining the compound according to claim 1, characterized in that in order to obtain a glassy surface layer and a dense surface layer, bischofite is additionally introduced into the magnesium chloride solution in an amount of 200 to 400 g / l, an iron sulfate solution with a density of 1.08-1 10 g / cm ³ in an amount of 0.1-0.4 by weight of the resulting solution of magnesium chloride, 10-20 percent solution of copper sulfate with a density of 1.08-1.10 g / cm ³ in an amount of 0.04-0, 13 by weight of the resulting solution of magnesium chloride, mix the resulting combined solution with magnesium powder zitovym caustic and carbon containing catalyst, the resulting mixture was incubated for 2-8 minutes, then mixed with the waste or filler, the resulting mixture was further mixed with 9-11 percent solution of sodium phosphate density of 1.05-1.07 g / cm ^3, the mixture obtained after mixing is placed in the form of final dimensions depending on the heat capacity of the filler, the inner surface of which is coated with a polymer. 3. The method according to p. 2, characterized in that the inner surface of the mold is coated with polystyrene or polyvinyl chloride. 4. The method according to p. 2, characterized in that the inner surface of the mold is coated with polyethylene terephthalate. 5. The method according to p. 2, characterized in that the inner surface of the mold is coated with polypropylene.

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