Explosives - Nitrate esters
Nitrate (NO3-) (CAS No. 014797-55-8) is an inorganic anion resulting from the oxidation of elemental nitrogen. It is an essential nutrient for plant protein synthesis and plays a critical role in the nitrogen cycle of soil and water. Nitrates are produced by natural biological and physical oxidations and therefore are ubiquitous in the environment (Ridder and Oehme 1974). Most nitrate compounds are strong oxidizing agents and some can react violently with oxidizable substances and may explode if exposed to heat or shock.
Nitrates are produced by natural biological and physical oxidations and therefore are ubiquitous in the environment. Most of the excess nitrates in the environment originate from inorganic chemicals manufactured for agriculture. Organic molecules containing nitrate groups are manufactured primarily for explosives or for their pharmacological effects
For many centuries gunpowder was the world's only explosive, and was not superseded until the discovery of guncotton. So long ago as 1832 Bracon discovered that woody fiber could be turned into an explosive by the action of concentrated nitric acid; and a few years later a French inventor, Dumas, tried to make cartridges of paper treated in similar fashion. If he had succeeded these would have been the first smokeless cartridges, but he failed; and it was not until 1845 that Schönbein, a German chemist, hit upon the proper method of treating cotton wool with nitric and sulphuric acids, so as to turn it into guncotton.
In 1847 an English firm, Messrs. Hall and Son of Faversham, began to manufacture guncotton, and military experts hailed it as the new explosive which would take the place of gunpowder. But this explosive was so terribly powerful that, when used in a gun or rifle, it blew the barrel to pieces. Worse than that, it was most dangerous to manufacture.
Two main problems had to be solved before it could be used as a gun propellant. First, the velocity of the explosion had to be reduced so that the charge weight required to propel the projectile would not shatter the gun tube. second, the density had to be increased so that a given charge weight would pack into a reasonable space. The first problem was solved in part by igniting NC instead of firing it with a detonator. The solution to the second problem actually solved both. In 1886, Vielle first colloided or gelatinized NC with alcohol and ether and, thus reduced the burning rate to acceptable levels. The procedure significantly increased the loading density of NC, establishing it as the foundational element in gun propellants used through the present day. Further developments resulted in materials that could be added to improve stowage qualities, reduce or eliminate flash, reduce hygroscopicity, reduce flame temperature, and even increase the propellant force or impetus.
Munitions manufacturing processes may generate nitrocellulose (NC) fines. Disposal of these fines is difficult because of their reactive nature. Composting has potential to be a safe and cost effective means of disposal. Open burning is no longer permitted in several states and is expected to banned nationally in the future. Open detonation is also the least acceptable form of disposal because of uncontrolled pollution by-products. In its role as the Department of Defense Manager for conventional munitions, Army must be able to dispose of Propellants/Explosives/Pyrotechnics production wastes. In composting, a controlled biological process, microorganisms convert biodegradable hazardous material to innocuous, stabilized by-products, typically at elevated temperatures between 50 - 55 °C. The increased temperatures result from heat produced by the microorganisms as they degrade the organic material in the waste. The NC fines are mixed with bulking agents and organic amendments, such as wood chips and animal and vegetable wastes, to enhance the porosity of the mixture. Maintaining moisture content, pH, oxygenation, temperature, and the carbon-to-nitrogen ratio achieves maximum degradation efficiency.
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