RU2421436C2 - Composition of granulated explosive substance (versions) and preparation method thereof - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to blasting works and can be used in preparing granulated explosives which can be used to blast mountain mass in the mining industry. The disclosed composition of granulated explosive substance contains granular ammonium nitrate, a water-resistant emulsion based on ammonia-carbamide solutions which contain mineral oil (industrial), ammonium nitrate, carbamide, water and an emulsifying agent, and dust-like combustible additives: coal and aluminium powder with particle size of 0.7-100 mcm. Two versions of the ratio of components are presented. The method of preparing the granulated explosive substance involves mixing ammonium nitrate with emulsions and solid combustible additives. In the process of preparing the explosive substance, aluminium powder, followed by the coal dust-like additive, is added to the granular ammonium nitrate after mixing with the emulsion.

EFFECT: composition of the explosive substance is easily processable and has good explosive properties.

3 cl, 1 tbl, 4 ex

Description

The invention relates to the development of granular explosive mixtures used for blasting on the earth's surface and in the face of underground workings of mines and mines that are not dangerous in gas and dust.

At present, granular explosives (granulites) are used in the mining industry of various countries, which are based on granular ammonium nitrate, combustible liquid additives (petroleum products) and special additives to stabilize the chemical and physical resistance of explosives.

Non-explosive solid combustible additives (aluminum powder, coal powder, urea, etc.) that prevent the flow of liquid additives from nitrate granules and increase the stability of explosive properties or explosives in the form of flaky or granular TNT are usually used as stabilizers.

Stabilizers are an essential component, since the quality of explosives and the energy of an explosion depend on their effectiveness (B.N. Kutuzov. Blasting operations. M: Nedra, 1980, p. 75).

Known mechanical mixtures of granular explosives (granulites, grammonites, igdanites, etc.) containing granular ammonium nitrate - 79-96% and combustible additives - 4-21%.

The manufacturing technology consists in the fact that in the preparation of granular explosives, "dense" ammonium nitrate is mixed with coal, carbon and nitrogen-containing organic substances in quantities that provide a stoichiometric ratio of the components.

A disadvantage of the known explosives is the instability and insufficient efficiency of explosive properties due to the low sensitivity of dense ammonium nitrate to the initiating impulse, as well as due to the poor holding ability of liquid combustible additives.

The closest to the proposed are explosive mixtures (patent RU No. 2230724, C1, 2003.02.12.), Which use granular ammonium nitrate of low bulk density, fine and polydispersed nitrate in various combinations. Liquid petroleum products or an oil-in-oil emulsion are used as fuel, including (wt.%): 60-69 ammonium nitrate, 11.7-16.2 sodium or calcium nitrate, 12-16 water, 4.1-8.5 liquid petroleum product or a mixture of liquid petroleum product with petrolatum, 1.0-2.0 emulsifier, 0.001-0.01 technological additives, or their mixture, or solid fuel - powdered organic fuel with a particle size of 0.007-4.05 mm, for example peat or lignin , wood flour, or coal, and / or urea with a particle size of 0.001-2.0 mm, and / or metal powders with a particle size of 0.005-0.07 m m, for example ferrosilicon or aluminum, or silicon aluminum, silicocalcium, and / or explosive individual compounds.

The compositions of explosive mixtures contain the following components, wt.,%:

Ammonium nitrate - 19-98;

Liquid or solid fuel - 81-2.

An addition of an oil-in-water emulsion and solid combustible additives to ammonium nitrate is made in order to stabilize and improve the explosive properties of explosive mixtures.

A method of manufacturing explosive mixtures is that all components included in their composition are mixed at the same time.

The disadvantages of the composition of the prototype and the method of their manufacture are:

- the joint use of granular nitrate and urea, especially when the content of granular explosive carbamide in the composition is more than 5% (especially with water), due to their hygroscopicity, significantly increases the moisture content of their mixtures, which leads to the washing off of liquid and solid combustible granules from nitrate , and sometimes turns this mixture into porridge during storage;

- the use of abrasive materials such as ferrosilicon, silicocalcium or silicic aluminum, especially with a particle size of 0.005-0.7 mm, leads to the flaking of combustible additives from the surface of the granules and their clumping, which impairs the technological and detonation properties of explosives (flowability, caking, uniformity of composition and stable explosive characteristics of explosives up to their failure in explosions). In this case, wear and tear of equipment for the preparation of explosives;

- when the particle size of the solid fuel (dust or powder) is more than 100 microns, it is impossible to obtain a uniform distribution of combustible additives on the surface of the nitrate granules, especially when the methods of their preparation are either mixing all components of explosives simultaneously or mixing solid combustible additives first with an emulsion , and then with granules of nitrate;

- the use of an emulsion containing perlite sand, glass or silicate (ash) microspheres (by the way, also abrasive materials), is a mixing of granular nitrate with emulsion explosives, because emulsions containing air inclusions are explosives. The introduction into the emulsion of sodium nitrite 6% (mass.) Or technological additives (for example, oxalic acid) is simply dangerous, because may lead to decomposition of nitrate and explosion;

- the use of liquid petroleum products with a low flash point of 35-80 ° C (fuel oil, diesel fuel, etc.) also poses an explosion hazard, especially if the water in the emulsion is less than 15%, given that waterproof emulsions are prepared at a temperature of 80-95 ° C.

Closest to the invention is a method of preparing a granular explosive (patent No. 2303023, С05В 31/28, 07/20/2007), which consists in the fact that the emulsion is first mixed with Poremite or Emulsolite in an amount of 5-10 wt.% from the composition of explosives with granular ammonium nitrate, and then the resulting mixture is mixed with coal dust and aluminum powder, the amount of which is 5-10 wt.% of the composition of granular explosives.

The disadvantage of this method is that it uses oxygen-balanced compositions (oxygen balance close to zero), well-known emulsions of Poremites, Emulsolites. Therefore, when air enters them from outside, for example, during their manufacture, transportation, transfusion, dosing, etc., these emulsions (with a decrease in their density) turn into explosive mixtures, which presents certain difficulties and increases the danger to the process of preparing granular BB Spontaneous explosions of Poremit emulsions are known during their manufacture and transportation. This requires the use of an increased amount of additional solid fuel (coal, aluminum) to obtain mixtures of granular explosives stoichiometric in composition, which requires longer and more thorough mixing of all components of the explosive.

Close to the invention are prepared using water-urea emulsions granular compositions of explosives (patent No. 2120927, C06B 21/00, 10.27.1998), including, wt.%:

Granular Ammonium Nitrate 84.6 Urea 3.2 Ferrosilicon 7.4 Diesel fuel 1.7 Water 2.2 Emulsifier 0.2

A disadvantage of the known explosives is the instability of the physicochemical and explosive properties due to the relatively high content of urea (which increases the hygroscopicity of nitrate) and water in the compositions of granular explosives. Since it is known that when moistened to 1.5%, nitrate granules reduce strength to such an extent that they break when rubbed in the fingers. (Z.G. Pozdnyakov, B.D. Rossi "Handbook of industrial explosives and explosives", Publishing house "Nedra", 1977, p.133,).

The essence of the invention lies in the fact that in the composition of granulite containing granular ammonium nitrate, liquid and solid combustible additives, a waterproof emulsion based on aqueous ammonia-urea solutions is used as a liquid combustible additive, and the mass fraction of components during their dosing during the manufacturing process of the proposed granular BB is, wt.%:

granular ammonium nitrate 85-89 emulsion matrix 7-5 pulverized coal 5.5-4.5 aluminum powder 2.5-1.5

Moreover, in the composition of the proposed granular explosive containing granular ammonium nitrate, emulsion and solid combustible additives, the components are presented in the following ratios, wt.%:

(ammonium nitrate, urea) - in total - 89 -93 (industrial oil, emulsifier), - in total - 0.5-0.15 pulverized coal - 4,5-5,5 aluminum powder - 1.5-2.5

For the preparation of explosives, it is proposed to use an emulsion (emulsion matrix) (Emulast AS-30FP TU 7276-014-163592200-2004) of the following composition wt.%: Mineral oil (industrial) - 4.5-7, ammonium nitrate 68-73, urea - 4-6, water - 15-20, emulsifier - 1.5-2.5, and as solid combustible materials coal and aluminum powder (non-abrasive materials) with a particle size of from 0.7 microns to 100 microns.

By introducing such an emulsion into the composition of granulite, new properties are achieved that increase the detonation stability of granular explosives. In particular, due to the exclusion of liquid petroleum products, the uniformity of mixing of combustible additives with granular nitrate properties is ensured. The content of urea in the emulsion and granular explosive increases their safety, because carbamide neutralizes undesirable acids that cause autocatalytic decomposition of ammonium nitrate. At the same time, urea (oxygen balance (- 80)) refers to combustible substances, which makes it possible to use additional combustible additives in explosives in a smaller amount.

In addition to the above, a new property is an increase in the explosive characteristics of granulite (brisance) due to the use of finely dispersed coal and aluminum powder in the explosive composition, due to the increased completeness of combustion of solid combustible additives during the explosion of explosives.

Thus, the combined use of granular ammonium nitrate, emulsion and combustible dusty additives in the composition of granulite provides a new effect - increasing the stability of explosive properties due to the uniform distribution of dusty additives and increasing the efficiency of technological and detonation properties, as well as the safety of explosives.

To date, waterproof emulsions based on a mixture of aqueous solutions of nitrate and urea with liquid petroleum products and an emulsifier have been used as the main component of cartridge emulsion explosives (Emulast AS-30FP TU 7276-014-163592200-2004), where by introducing gas-forming additives into them achieved the conversion of the emulsion from non-explosive to explosives.

The technology for preparing the cartridge-based Emulast explosive consists in introducing 30% of granulated nitrate into 70% of the previously obtained emulsion, and then an aqueous solution of sodium nitrite is added to the liquid plastic mixture at a temperature of 65-80 ° C, which, reacting with ammonium nitrate, it forms gas-air inclusions in the emulsion, which act as a sensitizer.

In the present invention, this emulsion, on the contrary, in contrast to the above-mentioned technology for producing emulsion explosives, is introduced into granular nitrate, as a result of which granular granular mixture is obtained, and the role of a sensitizer is played by combustible additives (coal, aluminum), which are then alternately introduced into it.

In the proposed explosive, the emulsion is used for a new purpose with a new positive effect. The amount of the added additive from the emulsion to granulite is limited to certain limits from 5 to 7%, which is due, firstly, to the carbamide content in the granular explosive composition (the most effective additive that helps to slow the thermal decomposition of ammonium nitrate is urea. It is known that the introduction of 0 , 2-0.3 urea significantly inhibits the decomposition of ammonium nitrate (Kilman Ya.I., Barkhatova G.S., Kuzina M.A. - Transactions of the GIAP, M., 1971, issue 6, p. ), secondly, the detonation ability of explosives, depending on the content Ania them granulated ammonium nitrate and fuel additives, and thirdly, uniformly distributed in the composition of explosive components.

A new method for the preparation of granular explosives, including mixing granular ammonium nitrate with emulsions and solid combustible additives, is that in the process of preparing explosives, aluminum powder is first introduced into it after mixing it with the emulsion, and then a coal dust additive. If the explosive composition is prepared in a different sequence, there is a likelihood of an uneven distribution of explosive components in the composition, as well as a deterioration in technological properties (loss of flowability).

The set of features, including the fact that after mixing the emulsion with granular nitrate, it is dusted first with one and then with another pulverulent additive, meets the criterion of “Novelty”.

By introducing an emulsion containing urea and liquid petroleum products with a flash point of at least 160 ° C, as well as non-abrasive solid fuels in the granulite composition, new properties are achieved that allow the technical solution to be recognized as meeting the criterion of “Significant Differences”.

In particular, by eliminating liquid petroleum products with a low flash point and abrasive coarse combustible additives, the safety of the explosive preparation process and the uniformity of mixing of combustible additives with granular nitrate increase the stability of granulite detonation. During the development and research under production conditions, it was found that the presence of urea (negative oxygen balance (-80)) instead of the ammonia part (oxygen balance (+20)) or sodium nitrate (oxygen balance (+40)) in the emulsion allows to increase its ductility and reduce its positive oxygen balance.

In this regard, in comparison with the manufacture of the granular composition according to patent No. 2303023, the process of preparing explosives is simplified (the mixing time of all components) and safety (air dust reduction) is reduced by reducing the amount of emulsion by 3%, and coal powder and aluminum powder by 2 %

The essence of the proposed method and the achieved results can be more clearly illustrated by the following examples.

Example 1. 150 g of coal powder and 150 g of aluminum powder were added to 700 g of the Emulast emulsion. All this was mixed in a mechanical stirrer. Got a plastic non-fluid mixture. Then, 140 g of the resulting mixture were added to 860 g of granular nitrate. Stirred in the auger. Got clumping and non-flowing mixture.

Example 2. Pre-mixed in a mechanical mixer 700 g of coal powder with 300 g of aluminum powder. Got a poorly flowing powder. Then 900 g of granular nitrate was mixed in the screw with 100 g of Emulsion Emulsion. Got a granular mixture, loose to the touch, greasy to the touch. Then, 930 g of granular nitrate, oiled with an emulsion, was mixed in a screw with 70 g of powder (a mixture of coal and aluminum). A satisfactorily granular granular mixture was obtained. However, its intergranular space was partially filled with combustible powder. When pouring this mixture from one container to another, dust emission was noticeable. At the same time, part of the combustible powder remained on the auger cavities.

Example 3. First, 900 g of granular nitrate was mixed with 100 g of Emulast emulsion, then 950 g of the above mixture was mixed with 50 g of coal powder. Then 980 g of this mixture was mixed with 20 g of aluminum powder. Mixing was carried out in the auger with the alternating supply of combustible components in granular nitrate. A well-granulated mixture of granular explosives was obtained. Then, in accordance with standard methods, the characteristics of this explosive were determined. The critical diameter is 120 mm; brisance - 26 mm; explosion efficiency - 36 mm. Static angle of repose, 44 degrees.

Example 4. First, 930 g of granular nitrate was mixed with 70 g of Emulast emulsion. Then, 940 g of the above mixture was mixed with 60 g of coal powder. Then 980 g of this mixture was mixed with 20 g of aluminum powder. Mixing was carried out in the auger with the alternating supply of combustible components in granular nitrate. A well-granulated mixture of granular explosives was obtained. However, in the intergranular space of the mixture, the presence, in a small amount, of combustible powders in the form of agglomerates was recorded. Then, in accordance with standard methods, the characteristics of this explosive were determined. The critical diameter is 100 mm; brisance - 28 mm; explosion efficiency - 38 mm. Static angle of repose, 36 degrees.

Example 5. First, 930 g of granular nitrate was mixed with 70 g of Emulast emulsion, then 980 g of this mixture was mixed with 20 g of aluminum powder. Then, 950 g of the above mixture was mixed with 50 g of coal powder. Mixing was carried out in the auger with the alternating supply of combustible components in granular nitrate. A well-granulated mixture of granular explosives was obtained. Then, in accordance with standard methods, the characteristics of this explosive were determined. The critical diameter is 100 mm; brisance - 28 mm; explosion efficiency - 38 mm. Static angle of repose, 32 degrees.

The results of comparative tests are shown in the table.

From the above examples, as well as from the table it is seen that the granulite compositions containing the proposed emulsion have increased explosive characteristics compared to granulites taken as a prototype. In addition, granulites containing an emulsion based on solutions of nitrate and urea are more loose and more stable in detonation properties than explosives prepared on other types of emulsions. In this case, explosive compositions prepared by mixing nitrate first with an emulsion, then with aluminum powder, and then with pulverized coal are the most effective.

The proposed granulites have the following advantages over the known explosives:

- have increased explosive properties;

- provide stable explosive properties during storage of explosives.

- ensure the safety of the preparation of explosives.

Table Test results of mixed explosives with different contents of emulsion and combustible additives Components and characteristics of explosives Granulitis (prototype) Samples of the compositions (experienced) Ammonium nitrate (prototype),% 86 - - - - - - - - Ammonium nitrate (proposed),% 90 90 89 81 80 86 86 87 Emulsion (prototype),% 7 - - - - - - - - Emulsion (proposed),% - four 5 5 10 eleven 7 7 5 Coal powder (prototype),% 5 - - - - - - - - Coal powder (proposed),% - four four 4,5 7 7 6 5.5 5.5 Aluminum powder,% 2 - - - - - - - - Aluminum powder,% 2 one 1,5 2 2 one 1,5 2.5 The value of indicators Bang day one thirty one thirty one thirty one thirty one thirty one thirty one thirty one thirty one thirty Brisance, mm 22 16 eighteen eighteen twenty 28 28 28 eighteen eighteen eighteen eighteen 24 24 28 28 26 26 Efficiency mm 36 32 34 34 35 35 38 38 34 34 34 34 36 36 38 38 37 37 Critical diameter of an open charge, mm 140 180 120 120 120 120 one hundred one hundred 120 120 120 120 120 120 one hundred one hundred one hundred one hundred Static angle natural slope, hail 62 80 36 36 36 36 32 32 57 62 57 62 38 42 40 42 36 36 Dynamic angle of repose, degrees 60 76 32 32 34 36 thirty thirty 54 62 55 56 36 40 38 40 34 34

Claims (3)

1. The composition of the granular explosive containing granular nitrate, a water-tight emulsion and dusty solid combustible additives, characterized in that an emulsion (emulsion matrix) based on aqueous ammonia-carbamide solutions of the following composition is used: mineral oil (industrial) - 4.5-7%, ammonia saltpeter - 68-73%, urea - 4-6%, water - 15-20%, emulsifier - 1.5-2.5%, and as solid combustible materials coal and aluminum powder with a particle size of 0.7 up to 100 microns, and the mass fraction of the components when they are dosed in the process the manufacture of granular explosives is, wt.%:
granular ammonium nitrate 85-89% emulsion matrix 5-7% pulverized coal 5.5-4.5% aluminum powder 2.5-1.5% 2. The composition of the granular explosive containing granular nitrate, a waterproof emulsion and dusty solid combustible additives, characterized in that the components are taken in the following proportions, wt.%:
(ammonium nitrate, urea) - in total 89-93 (industrial oil, emulsifier) - total 0.5-0.15 pulverized coal 4.5-5.5% aluminum powder 1.5-2.5% 3. The method of preparing a granular explosive according to claim 1, comprising mixing ammonium nitrate with emulsions and solid combustible additives, characterized in that during the preparation of an explosive in granular nitrate after mixing it with an emulsion, aluminum powder is first introduced, and then a coal dust additive.