Military explosives manufacture

Wayne Cocroft, Dangerous Energy The Archaeology of Gunpowder and Military Explosives Manufacture (Swindon English Heritage, 2000), 158-159. 

POLLUTION abatement IN THE US MILITARY EXPLOSIVES AND PROPELLANTS MANUFACTURING INDUSTRY... 

N.E.C. is the major manufacturer with a complete range of explosives and accessories, with factories in Scotland, Wales and England. Explosives and Chemical Products Ltd., with factories in England, is the other manufacturer of explosives for sale. The major commercial manufacturer of ammunition is Imperial Metal Industries (Kynoch) Ltd. at Witton near Birmingham. The British Government has of course a number of Royal Ordnance Factories and establishments to cover all aspects of military explosives. 

From the days of Nobel to about 1950 the scientific basis of commercial explosives remained relatively unchanged, although continuous and numerous improvements in manufacturing methods occurred throughout the world. There were, however, many advances in military explosives, note of which will be made later. These advances were, of course, largely due to the two world wars, which occurred since the death of Alfred Nobel. There were also many advances in the development of permitted explosives designed for use in gassy coal mines. 

The military explosives RDX and HMX are manufactured from the 3 components using the Bachman process. Some of the possible mixtures may lead to fires in open vessels and explosions under confinement, and the exothermic and other effects (some calculated by the CHETAH program) for a wide range of mixtures are presented as ternary diagrams. It was also found that acetic anhydride layered onto solutions of ammonium nitrate in nitric acid exploded, owing to formation of acetyl nitrate. 

Industrial activities involving transportation, pipelines, laboratories, minerals extraction, mining, explosives manufacturing, pyrotechnic manufacturing, or military uses are not considered. 

At the same time, the need to manufacture military explosives created a demand for toluene to make TNT. Ironically, the chemistry that makes for good octane characteristics has little to do with that of explosives. 

Military explosives are required to meet stringent criteria because apart from a requirement for high performance, the military needs to be able to safely store them for decades, transport them anywhere from the poles to the equator, handle them under battlefield conditions, and still have them fuUy functional. In addition, availability of raw materials, ease of manufacture, and cost are important factors. Most candidate explosive compounds do not meet all these requirements. 

The most important nitrolysis reaction to date is the formation of RDX (3) and HMX (4) from the caged methylenediamine known as hexamine (104). These important military explosives were first mass manufactured by this route towards the end of the Second World War and they are still prepared by this route today. The process uses a mixture of acetic anhydride, ammonium nitrate and nitric acid. The nitrolysis of hexamine is one of the most widely studied reactions in the history of explosives. Many other cyclic and linear polynitramines have been isolated from these reactions and this rich chemistry is discussed in more detail in Section 5.15. 

Uses. Once widely used as a military explosive but no longer manufactured or used in the United States... 

The most widely used inorganic ester of cellulose is cellulose nitrate (CN), also called nitrocellulose or gun cotton. Celluloid is produced from a mixture of CN and camphor. It was first made in 1833 when cellulose-containing linen, paper, or sawdust was reacted with concentrated nitric acid. It was the first synthetic cellulose product that was recognized. Initially, CN was used as a military explosive and improvements allowed the manufacture of smokeless powder. A representation of CN is given in structure 9.7. 

Military explosives must be physically and chemically stable over a wide range of temperatures and humidity for a long period of time. They must be reasonably insensitive to impact, such as those experienced by artillery shells when fired from a gun or when they penetrate steel armor. They are used for a number of applications. They are fired in projectiles and dropped in aerial time bombs without premature explosion. The raw materials necessary to manufacture such explosives must be readily available for production in bulk during wartime. 

The preparation of infusible (loose powder) ammonium nitrate mixtures is usually carried out in the same way as the manufacture of composite mining explosives. Since the military explosives are not very sensitive to mechanical stimulants, and it is important to obtain a high density, mixing is usually performed by edge runner mills. 

TNT has a number of advantages which have made it widely used in military explosives before World War I and up to the present time. These include low manufacturing costs and cheap raw materials, safety... 

Most military explosives are solid compounds which are manufactured in granular form, with bulk densities of less than 1 g cm-3. These granular compounds are then mixed with other explosive or inert additives to give explosive compositions with densities between 1.5 and 1.7 g cm 3. The explosive compositions are then cast, pressed or extruded into their final form. 

See in Vol 8, P317-L to P324-L, under Pollution Abatement in the US Military Explosives and Propellants Manufacturing Industry N85-R to N86-L, under Nitration and under sub-topic Disposal of Waste TNT in article on TNT in Vol 9... 

According to the U.S. Standards ammonium nitrate for production of military explosives should contain 99.0% of NH4N03, no more than 0.02% free nitric acid, 0.18% of water-insoluble material, 0.50% of ammonium sulphate and 0.5% of ammonium chloride. The product should be free from alkalis and metal nitrates. A substance of similar purity is used for the manufacture of mining explosives. 

Wilbrand, in 1863. first prepared tnniiromluenc (TNT). C(,H (CH-.) (NO ),. The material was not manufactured in production quantifies until about 1900. The German military recognized the advantages of TNT as a replacement for picric acid, which they had used earlier. TNT was used extensively during World Wat I and became a standard military explosive. 

The Manufacture and Testing of Military Explosive s ,McGraw-Hill,NY (1920), 114-17 5)Van Gelder 8t Schlatter(1927),3fF(History of BkPdt in the US) 6)H.S.Deck,Army0rd 7,34 (1926)(Impact test value for BkPdr dust)... 

In each step several isomers are formed—only one of the possibilities in each case is indicated above—and the ortho and para compounds both go through similar series of reactions. The product is too sensitive and in the wrong physical state (liquid) for use as a military explosive. In short, for the manufacture of... 

Remotely deployable submersible sensors capable of monitoring contaminants both in time and in location have a variety of applications [19]. Such ability to perform in situ measurements of explosives is important for improving the efficiency of characterization and remediation of sites that are former military munitions manufacturing, storage, and demilitarized zones and are contaminated with high levels of explosive compounds. 

The demand for nitrogen in a chemically fixed form (as opposed to elemental nitrogen gas) drives a huge international industry that encompasses the production of seven key chemical nitrogen products ammonia, urea, nitric acid, ammonium nitrate, nitrogen solutions, ammonium sulfate and ammonium phosphates. Such nitrogen products had a total worldwide annual commercial value of about US 50 billion in 1996. The cornerstone of this industry is ammonia. Virtually all ammonia is produced in anhydrous form via the Haber process (as described in Chapter 2). Anhydrous ammonia is the basic raw material in a host of applications and in the manufacture of fertilizers, livestock feeds, commercial and military explosives, polymer intermediates, and miscellaneous chemicals35. 

Tetryl is a synthetic compound that does not occur naturally. It was once widely used as a military explosive but is no longer manufactured or used in the United States (see Chapter 4). Effluents and... 

RDX forms orthorhombic crystals with a melting point of 206 Celsius. 1 Gram dissolves in 25 milliliters of acetone, but its solubility in alcohol, ether, ethyl acetate, and glacial acetic acid is even less. It is insoluble in water, carbon tetrachloride, and carbon disulfide. RDX is one of the most important military explosives known to man. It is highly versatile, being resistant to heat, shock and percussion, and is capable of being alloyed with many different secondary explosives. RDX is very well known in several of the most important explosives compositions. These compositions include semtex, C4, and composition B, all of which are widely used in military operations. RDX is by far one of the most important explosives in occurrence, and it is manufactured on an industrial scale. 

The art of using mixtures of chemicals to produce explosives is an ancient one. Black powder—a mixture of potassium nitrate, charcoal, and sulfur—was being used in China well before 1000 a.d. and has been used through the centuries in military explosives, in construction blasting, and in fireworks. The DuPont Company, now a major chemical manufacturer, started out as a manufacturer of black powder. In fact, the founder, Eleuthere du Pont, learned the manufacturing technique from none other than Lavoisier. 

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