Mercury fulminate development

Explosives. Mercury, in the form of organic complexes, eg, mercury fulminate [628-86-4] has had long usage in explosives (see Explosives and propellants). In the United States all mercury for use in explosives is diverted to military uses. An explosive based on mercuric 5-nitrotetra2ole [60345-95-1] has been developed, but its use is on a small scale and in research and development only (3). 

Chandelon Also spelled Chandelen. A process for making mercuric cyanate, (mercury fulminate) by dissolving mercuiy in nitric acid and pouring the solution into aqueous ethanol. Developed by Chandelon in Belgium in 1848. 

Mercury Fulminate. Ryabinin suggests that these cases, which appear to be exceptions, may be due to greater ease of developing high temp in expl on initiation at high pressure, and to higher thermal conductivity... 

According to Romocki [2], in 1630, the Dutchman, van Drebbel was the first chemist to investigate mercury fulminate, and explosive gold . The first description of the laboratory preparation of mercury fulminate is given in Kunkel s book Laboratorium Chymicum published in 1690 [3]. This substance was described again by Howard in 1799-1800 [4]. No further discoveries of other primary explosives were made until the development of modern chemistry. 

Thus, at a pressure of 200 kg/cm2 the substance nears the condition of being dead pressed . In spite of the fact that burning under this condition passes to detonation with difficulty, when greatly compressed the material maintains its ability to be detonated by a cap. Thus, 0.4 g of tetrazene, pressed under a pressure of 200 kg/cm2, develops its maximum power, i.e. 21.1 g of sand crushed, when initiated with 0.4 g of mercury fulminate. The difficulty in passing from burning to detonation makes tetrazene unsuitable for detonators and its application is thus limited to... 

The pivoted magazine was too complicated and subsequent development by other workers was geared toward a more convenient and efficient means of presenting the mercury fulminate to the firearm. 

In 1805 the Reverend Alexander Forsyth used mercury fulminate as the basis of his primer composition, and from this time the percussion system developed into today s highly reliable, universally used, percussion primer compositions. This development which started in 1805 still continues today, and manufacturers are very reluctant to release details of their compositions. 

Up to this time primers had fallen into three categories mercuric and corrosive, nonmercuric but corrosive, and mercuric but noncorrosive. Because of the disadvantages of mercury fulminate and potassium chlorate the main objective of primer development was to produce a primer with satisfactory ignition properties without the use of these two compounds. An early NCNM priming composition used copper ammonium nitrate to replace mercury fulminate, and potassium nitrate to replace potassium chlorate. The composition was ... 

Another similar design contains a firing pin which on impact detonates 0.42 g of mercury fulminate (42%) and potassium chlorate (58%) mixture. An exploding/incendiary bullet with its own firing pin was also developed,... 

At the start of 1978 the particle analysis method183 replaced the flameless atomic absorption bulk elemental method184 as the firearm residue detection method in the NIFSL. Since then the particle analysis method has been substantially improved by the use of a sample concentration/cleanup procedure,185 the addition of a backscattered electron detector, and the development of an automated residue detection system.186 187 Despite these improvements the technique remains costly and labor intensive. Certain aspects of the system required further work, in particular, the particle classification scheme discharge particles from mercury fulminate-primed ammunition and discharge particles from new primer types (Sintox). 

The particle classification scheme, developed as described in reference 200, did not include mercury fulminate-primed ammunition, which is frequently encountered in Northern Ireland, and is currently manufactured in some Eastern Bloc countries. 

Swedish inventors Emmanuel Nobel and his son Alfred took an interest in this powerful liquid explosive and produced it commercially in 1862. However, its transportation and its handling were very hazardous, and eventually Alfred Nobel discovered that NG absorbed into a granular type of material (kieselguhr) was still explosive, but was much safer to handle and use than the straight liquid. This new invention, called dynamite, was difficult to ignite by the usual methods used for pure NG. Therefore, also in 1867, Alfred Nobel devised the blasting cap using mercury fulminate. With this development dynamite became the foundation of the commercial explosives industry. 

Silver fulminate is much more sensitive than mercury fulminate. Since its detonation development distance is very short, its initiation effect is superior to that of mercury fulminate, but the compound is too sensitive to be used commercially. 

By 1867, Alfred Nobel was on the market with a nonelectric blasting cap filled with mercury fulminate, for use with his new dynamite a replacement for black powder. The fulminate-filled cap became a spark actuated or high-tension blasting cap under the development of American inventor, H. Julius Smith in 1868 (Figure 24.7). 

A few initiating co lpositions with tetrazene have been described in the En-O clopedia [148]. The most important seems to be Sinonydsatz developed in Germany as a replacement for mercury fulminate mixtures, h proved to be non corrosive and did not erode barrels of firearms. Their composition was lead styphnate 25-55, tetrazene 1.2—5.0, barium nitrate 25—45, lead dioxide 5-10, anlhymony sulphide 0-10, calcium silicide 3-15, powdered glass 0-5%. 

Nitro Compounds as Explosives.—Nitro compounds prepared from aromatic hydrocarbons and certain of their derivatives were very important explosives used in the recent war. The compounds differ markedly in the properties which are characteristic of explosives namely, (1) sensitiveness to shock, (2) explosive force, and (3) the velocity of the explosion through the substance. If (1) is very high the explosive can not be transported very safely (2) determines the amount of the explosive to be used if (3) is very high the pressure is developed to its maximum so suddenly that rupture of the gun in which it is used may take place. Substances which are very sensitive to shock are used as detonators or boosters a small amount of the material is exploded by the trigger and the explosive wave set up causes the explosion of the less sensitive material. Mercury fulminate, lead azide, Pb(Ns)2, and several nitro derivatives of aniline (see below) are used for this purpose. 

Dependence of detonation velocity on density is shown in Fig. 2.1. Mercury fulminate belongs to the group of primary explosives with a long predetonation zone. In other words, it means that it takes a long time, and uses significant amounts of charge, before the decomposition reaction accelerates from simple initial impulse to fully developed detonation (slow deflagration to detonation transition... 

---