RU2092565C1 - Method of destruction of large-sized objects - Google Patents

Abstract

FIELD: blasting of large-sized monolithic objects, for instance, waste of metallurgical industry - scraps formed slag and metal solidified after discharge from the blast furnace or melting furnace. SUBSTANCE: explosive charge with a striker is positioned at a definite distance from the body to be destructed. At initiation of the explosive charge a striker with a mass of 2 to 4 kg is formed, which is propelled by gaseous detonation products to the body to be destructed at definite kinetic energy E. As a result of dynamic action of the striker, a high-pressure zone arises in the body at a level of 10⁵ MPa (10⁶ atm.), the substance crystalline structure gets destructed. This causes mechanical crushing of the substance with subsequent scattering of lumps from the point of impact. The propagating shock wave displaces the compression zone throughout the whole body, causing the required destruction of substance within the whole volume. The maximum energy of detonation products is imparted to the striker, when the explosive mass-to- propelled body mass ratio is 2:6. EFFECT: enhanced efficiency. 2 cl, 3 dwg

Description

 The invention relates to the field of blasting operations for the destruction of large-sized monolithic objects, for example, scrap scrap from the metallurgical production of slag and metal that solidified after draining from a blast furnace or smelter, which falls into a ladle with slag and which is expediently separated from the slag, crushed and sent to remelting.

 In connection with the increase in the cost of mining products, the increase in the cost of transportation services for the transportation of ore and coal, and also due to the possibility of recycling almost all components of the waste generated during metallurgical production, the issue of utilization of solidified waste of cast iron, steel, slag (" cakes "," scraps ") by destroying them to sizes that make it easy to transport pieces for processing.

 A known method of destruction, including the undermining (initiation) of the explosive charge (EX) on the surface or inside the destructible body and its destruction by the energy of the explosive transformation. However, this method requires preliminary preparation of the destructible body in terms of the formation of the cavity for laying explosive charges inside. Otherwise, the energy of detonation products will be dissipated into the external environment, producing little useful work to destroy the body. The presence of nearby buildings imposes a limit on the power of the explosion, not allowing to break the scraps and cakes on the territory of the metallurgical plant. The preliminary formation of a cavity inside the body for the efficient use of explosive charge energy (in order to reduce its mass) is very laborious and economically inexpedient.

 These disadvantages are eliminated in the method of destruction, which includes multiple dynamic loading of the destructible body due to the inhibition of a moving striker in it, which has proven itself in the destruction of old buildings, because all the impactor’s energy is localized at the point of contact with the destructible body. But with the destruction of scraps, this method is ineffective due to the relatively low power.

 The aim of the proposed invention is to increase the efficiency of destruction by optimizing the dynamic effects both in energy and in the direction of impact while reducing the complexity and material consumption of destruction, allowing the use of blasting in the waste dump of a metallurgical plant, as well as achieving a very definite result of destruction.

 This is achieved due to the fact that in the method of destruction of objects, for example, waste from metallurgical production or any structural elements, the energy exerted by the dynamic impact on the object is provided by the kinetic energy of the propelled body at the time of impact on the object and is determined by the value (1.5 3) of the product the mass of the object by the amount of energy spent on crushing a unit mass of the substance of which the object consists, and the mass of the explosive is chosen from the level that it will be 2-6 masses of missile a, while throwing is carried out aiming in the zone of the alleged location of the center of mass of the object with a radius of 0.05 0.03 from the overall size of the object in the frontal plane, and after the onset of crack formation in the body of the object after the introduction of the body thrown by the explosion, the gaseous products of the explosion are fed into the cracks, then gaseous products are scattered outside the object. If the structure of the object includes several very different substances, then the throwing body is provided with kinetic energy, which is not less than the sum of the products of the masses of the substances that make up the object, by the energies used to fragment the mass units of the corresponding substances. When the destruction of the object of the layered structure, which consists of several components, throwing is carried out from the side of the exit to the surface of the component with more energy, which goes to the crushing of a unit mass, along the geometric center of the outer surface of this component.

 Comparison of the claimed technical solution with the prototype made it possible to establish compliance with the criterion of "novelty." When studying the known technical solutions in the art, the features that distinguish the claimed invention from the prototype were not identified and therefore they provide the claimed technical solution with the criterion of "inventive step".

 In FIG. 1 shows the initial position of the object intended for destruction and the explosive charge with a missile striker; in FIG. 2 the process of interaction formed by the explosion of the projectile and the object; in FIG. 3 - the moment of introduction of the striker into the body of the object, crack formation, leakage of gaseous products of explosion into the cracks and the beginning of the destruction of the object.

 In FIG. 1 3 1 explosive charge; 2 missile element; 3 destructible body; 4 explosion-shaped hammer; 5 high pressure zone at the moment of dynamic impact of the striker; 6 gaseous explosion products; 7 - cracks.

The explosive charge 1 with the propelled body 2 is located at some distance from the body 3 intended for destruction. When the explosive charge is initiated, a projectile 4 weighing 2-4 kg is formed, which is thrown into the destructible body by the gaseous products of the explosion. As a result of the dynamic impact of the projectile in the body, a high pressure zone 5 with a level of 10 ⁵ MPa (10 ⁶ atm) arises, and the crystal structure of the substance is destroyed. The consequence of this is either the transition of the substance to another phase state (melting, evaporation), or the mechanical crushing of the substance with the subsequent expansion of the pieces from the place of impact. A propagating shock wave will move the compression zone throughout the body, causing the desired transformation of the substance throughout the volume.

где ρ_ув давление на фронте ударной волны;
ρ_a и ρ_н начальные плотности первой и второй среды

ρ_1у, ρ_2у- плотности этих сред на фронте ударной волны
U_т скорость удара
U_цв скорость движения раздела двух сред, можно установить минимальные величины давления и скорости метания ударника, необходимые для достижения той или иной степени разрушения вещества, в частности, для механического дробления:

где ε_к энергия, идущая на дробление единицы массы среды.Using the known relation (4)

where ρ _uv pressure at the front of the shock wave;
ρ _a and ρ _{n are the} initial densities of the first and second medium

ρ _1y , ρ _2y are the densities of these media at the shock front
U _t impact speed
U _{cv the} speed of movement of the separation of the two media, you can set the minimum pressure and throwing speed of the projectile necessary to achieve a degree of destruction of the substance, in particular, for mechanical crushing:

where ε _{k is the} energy used for crushing a unit mass of the medium.

Obviously, for the destruction of the whole body (object), the condition must be met:
E _k = K • M • ε _k (4)
where K = (1,5 3) the safety factor;
M is the mass of the destructible body (object);
k the energy of fragmentation of the unit mass of the component of the object;
E _{to the} kinetic energy of the propelled body.

The values of ε _k for various materials range from 10 ⁹ erg / g for iron to 5 10 ⁵ erg / g for granite and slag.

 Studies show that the maximum energy of detonation products is transferred to the projectile with a ratio of the mass of the explosive to the mass of the propelled body 2-6. Outside the interval, either the mass of the explosive is insufficient to accelerate the striker, or it is excessive, which is economically and environmentally unreasonable.

 To increase the efficiency of the method, it is necessary that the aiming when throwing the hammer is carried out in the zone of the proposed location of the center of mass in the frontal projection of the body being destroyed, since in this case, the compression wave in the body will propagate to its boundaries more evenly. The pressure difference in the wave front at the boundary of the body in its various parts will be minimal, i.e. explosive energy will be used rationally and body fragmentation will occur throughout the entire volume.

 In order to reduce the complexity of the destruction in the method, an aiming zone is set, the dimensions of which avoid the need for devices and aiming devices and provide sufficient reliability of destruction. The shift of the contact zone of the projectile from the center of mass by more than 0.3 of the overall size of the object being destroyed reduces the efficiency of the method due to asymmetric loading and edge energy dissipation.

 When bodies or objects consisting of several components are destroyed, the law of additivity comes into force when the properties of an object are characterized by the sum of the properties of its constituent components.

 Before exposure, the explosive charge is placed in such a way and at such a distance that after the formation of the initial cracks, the gaseous products of the explosion flow into them and increase the stress gradient in the destructible body due to the fact that the dispersion of the gaseous products of the explosion from the outside occurs much faster than the outflow of gas from the cracks. In the end, this leads to an increase in the efficiency of the method due to the spalling effect under the influence of internal exposure to gases.

 When the destruction of the object of the layered structure, which consists of several components, throwing is carried out from the side of the exit to the surface of the component with more energy, which goes to crushing a unit mass, along the geometric center of the outer surface of this component in the direction of the proposed center of gravity and close to the normal of the outer surface . Naturally, in this case, the difference in size of the crushed pieces of various components is reduced, because most of the energy is spent on crushing the most durable component, the remaining part of the energy is crushing less strong components. Otherwise, the energy of the projectile would immediately be spent on the destruction of the less strong component into very small fractions, and its balance would not be enough to crush the strong component.

 The proposed method was tested during the development of the dump of the Tula Metallurgical Combine NPF TIOM and confirmed its effectiveness, efficiency and acceptable environmental friendliness by optimizing the required blast power when a certain fracture result is achieved.

Claims (2)

1. The method of destruction of large-sized objects, mainly waste of metallurgical production, using an explosion, characterized in that the destruction of waste in the form of scrap or a solid structural object is carried out by a hammer, driven by a cumulative charge with a mass equal to 2 6 masses of the hammer, and calculate the distance from the cumulative charge with the striker to the surface of the object of destruction and throw the striker aiming at the center of mass of the destroyed object in the frontal plane with the kinetic nergiey E, corresponding to the ratio of
E = K • M • ε _k ,
where K (1,5 3) safety factor;
M is the mass of the destroyed object;
ε _to - specific energy of crushing of the object.  2. The method according to claim 1, characterized in that for the destruction of a large-sized object from several dissimilar components, a zone of location of a component having a higher specific crushing energy is determined, and throwing is carried out from the side of this zone at the geometric center of its outer surface.

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