Explosives ammonium nitrate used

As noted above (p. 36), the ammonium nitrate used for these explosives should be porous and should retain 7% of the oil without tendency to segregate on standing. A further requirement in modem practice is that the mixture, when blown into boreholes by compressed air, should break down to give a proportion of fine powder which increases both the density of loading and the sensitiveness of the mixture (see p. 141). 

Miedziankit was one of the most widely used non-military explosives in Germany, Russia and Poland before, during and immediately after World War I, when there was a need to economize in the nitrates, including ammonium nitrate, used for military purposes. 

Nitrate explosives. The term explosion is applied to the effect produced by a sudden change in the pressure of one or more gases. This may be the result of either chemical or physical changes—that is, the sudden liberation or absorption of gases in chemical reactions or the sudden formation of gases from either liquids or solids. Because certain nitrates decompose readily with liberation of gaseous products, these substances are useful in compounding a variety of commercial explosives. Ammonium nitrate is stable under ordinary atmospheric conditions and may be handled safely in small quantities, even at elevated temperatures. When the dry salt is heated, it decomposes with liberation of nitrous oxide and water,... 

A mixture of ammonium nitrate and light oil forms a low strength explosive which is used as a blasting compound for mines and in industrial engineering. This class of explosives is named ANFO explosives (ammonium nitrate fuel oil explosives). The density of ANFO explosives is 800-900 kg/m3 and the detonation velocity is 2500-3500 m/s. The sensitivity to initial detonation is very low, and the handling of ANFO explosives is thus easier than that of other industrial explosives. 

A prill is a small, porous pellet of ammonium nitrate formed by a series of chemical and physical processes. Prilled ammonium nitrate used in blasdng operations is referred to as explosives grade, low density, or industrial grade ammonium nitrate. 

It is prepared by the direct nitration of toluene with a mixture of nitric and sulphuric acids. TNT is a very stable, violent and powerful high explosive, but less sensitive to shock and friction than picric acid. It is widely used as a filling for shells, bombs, etc. often mixed with ammonium nitrate and other high explosives. The lower grades of TNT may contain isomers which under hot storage conditions may give rise to exudation. 

Picric Acid and Ammonium Picrate. Picric acid (PA) (2,4,6,-trinitrophenol) was the first modem high explosive to be used extensively as a burster ia gun projectiles. It was first obtained by nitration of iadigo, and used primarily as a fast dye for silk and wool. It offered many advantages when compressed, it was used as a booster for other explosives, and when cast (melting poiat 122.5°C) served as a burster ia shell it was stable, iasensitive, nonhygroscopic, relatively nontoxic, and of high density when cast, and could be made economically by simple nitration. 

Ammonium nitrate-based explosives account for about 97% of total U.S. industrial explosive consumption. Coal mining in the United States formed about 65—68% of the demand for explosives in 1991. The remaining uses were quarrying and nonmetal mining, 15% metal mining, 10% constmction, 7% miscellaneous uses, 3—4%. The properties of ammonium nitrate are given in Table 18 (173,239—242). 

Ammonia from coal gasification has been used for fertilizer production at Sasol since the beginning of operations in 1955. In 1964 a dedicated coal-based ammonia synthesis plant was brought on stream. This plant has now been deactivated, and is being replaced with a new faciUty with three times the production capacity. Nitric acid is produced by oxidation and is converted with additional ammonia into ammonium nitrate fertilizers. The products are marketed either as a Hquid or in a soHd form known as Limestone Ammonium Nitrate. Also, two types of explosives are produced from ammonium nitrate. The first is a mixture of fuel oil and porous ammonium nitrate granules. The second type is produced by emulsifying small droplets of ammonium nitrate solution in oil. 

Most limestone quarries use either 100% ammonium nitrate [6484-52-2] (fertilizer grade) and fuel oil (ANFO), or a combination of ANFO and ammonium or gelatin dynamite, for blasting (see Explosives and propellants, explosives). After blasting, oversized boulders usually are reduced to manageable sizes by drop ball cranes. 

In commercial practice, powdered explosives on an ammonium nitrate basis are used in most cases. Typical detonation velocities are between 1800 and 3500 m/s depending on the metal system to be bonded. The lower detonation velocity range is preferred for many metal systems in order to minimize the quantity of solidified melt associated with the bond-zone waves (12). In addition, subsonic detonation velocity explosives are required for the parallel cladding technique in order to avoid attached shock waves in the coUision region, which preclude formation of a good bond. 

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