Mercury fulminate manufacture

Beside this basic method of manufacturing mercury fulminate, which is widely practised, there are alternate processes. Angelico [11] recognized that mercury fulminate is formed by treating a mercury solution in an excess of nitric acid with a concentrated aqueous solution of malonic acid in the presence of a small amount of sodium nitrate. The reaction results in a considerable rise of temperature, C02 evolution and the precipitation of the fulminate (L. W. Jones [12]). 

Fig. 38. General view of plant for manufacturing mercury fulminate in Atlas Powder Company, according to Davis [62]. On the left, conical flasks with mercury nitrate in nitric acid. On the right, reaction flasks.

Use Nitration of aromatic organic compounds, felt manufacture, mercury fulminate manufacturing. 

The original initiating explosive used by Nobel and all manufacturers for many years was mercury fulminate. This had the disadvantage of decomposing slowly in hot climates, particularly under moist conditions. For this reason mercury fulminate is no longer widely used. In most countries it has been replaced by a mixture of dextrinated lead azide and lead styphnate. In the U.S.A. some detonators are made containing diazodinitrophenol. 

Uses Determining fat content in milk solvent for alkaloids, fats, oils manufacturing isovaleric acid, isoamyl or amyl compounds, esters, mercury fulminate, artificial silk, smokeless powders, lacquers, pyroxylin photographic chemicals pharmaceutical products microscopy in organic synthesis. 

Mercury fulminate [Hg(CNO)2] is very explosive and is used to manufacture blasting caps and detonators. 

The unsaturated nature of fulminic acid accounts for its tendency to polymerize and suggests that polymers constitute the brown impurity produced in the manufacture of mercury fulminate. The ability of fulminic acid to polymerize is also proved by the formation of cyamelide (I). It has also been established that an ether solution of fulminic acid is converted into metafulminuric acid on standing ... 

There are numerous specifications for the technical manufacture of mercury fulminate. They may be divided into three groups ... 

One of the earliest descriptions of the manufacture of mercury fulminate given by Chevalier [59] is as follows 300 g of mercury are dissolved in 3000 g of cold nitric acid (54% HN03, s.g. 1.34) and the solution is poured into a flask containing 1900 g of 90% alcohol. After few minutes a vigorous reaction begins and crystals are precipitated. On completion of the reaction 238 g and 158 g of alcohol are added in turn. The fulminate is filtered off through a cloth filter and carefully washed free of acid with water. The yield is 118-128 parts of fulminate per 100 parts of mercury, i.e. 83-90% of theoretical. 

Solonina [10] gives two methods for the manufacture of mercury fulminate the first (a) produces a white fulminate and the second (b) a grey one. 

Waste substances from the manufacture of mercury fulminate are ... 

Curtius added lead acetate to a solution of sodium or ammonium azide resulting in the formation of lead azide. In 1893, the Prussian Government carried out an investigation into using lead azide as an explosive in detonators, when a fatal accident occurred and stopped all experimental work in this area. No further work was carried out on lead azide until 1907 when Wohler suggested that lead azide could replace mercury fulminate as a detonator. The manufacture of lead azide for military and commercial primary explosives did not commence until 1920 because of the hazardous nature of the pure crystalline material. 

Fulminic acid. HONC, and the fulminates are violently explosive. Utilizing this properly, mercuric fulminate. Hg(ONC) - HiO. is used as a detonator for other explosives. Mercury fulminate is made by the reaction of ethyl alcohol and mercuric nitrate in excess of nitric acid, from which insoluble mere-uric fulminate separates. Silvei fulminate. Agl ONC). is more explosive than mercuric fulminate, and is used in the manufacture of firecrackers Free fulminic acid may be obtained by reaction of potassium fulminate and excess of ether. It volatilizes with the ether upon distilling, and changes rapidly to meiufulminic acid. Related to fulminic acid is fulminuric acid, (HONCn. or NOy-CH(CN)-CONH-. 

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. 

Mercury fulminate/potassium chlorate-based primer compositions are currently manufactured by some Eastern Bloc countries, although they also manufacture compositions based on lead styphnate. 

It is interesting to note that the primer appears to be based on mercury fulminate, antimony sulfide, and potassium chlorate, that is, mercuric and corrosive, and that the ammunition was manufactured in 1982. 

The analysis of primers supports the statement that Communist Bloc countries frequently use mercury fulminate primers and it is also worth noting that the same applies to ammunition manufactured in France, at least for the time period involved. According to the literature there has been no mer-... 

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. 

A percentage recovery of 48.73 is disappointing. The variation in the amount of mercury initially present in the ammunition (see Table 22.4) is probably due to deterioration of the mercury fulminate over a long period, the ammunition having been manufactured in 1943. The variation would... 

If small amounts of copper and hydrochloric acid are added to the reaction mixture, a white product is obtained. Mercury fulminate is stored under water. It is dried at 40 °C (104 °F) shortly before use. Owing to its excellent priming power, its high brisance, and to the fact that it can easily be detonated, mercury fulminate was the initial explosive most frequently used prior to the appearance of lead azide. It is used in compressed form in the manufacture of blasting caps and percussion caps. The material, the shells, and the caps are made of copper. 

Mercury fulminate has no longer a monopoly as a primer. In some of its uses it has been replaced by azides, particularly lead azide in some others chlorate primers have taken its place. Chlorates and perchlorates are also being used in industrial explosives and can now be readily manufactured by means of electrochemical processes. 

Lead azide is a more efficient detonating agent than mercury fulminate. It requires a higher temperature for its spontaneous explosion, and it does not decompose on long continued storage at moderately elevated tem )cratures. It cannot be dead-pressed by any pressure which occurs in ordinary manufacturing operations. Lead azide pressed into place in a detonator capsule takes the fire less readily, or explodes from spark less readily, than... 

Similarly, there was no correlation between urinary mercury levels (60-245 g/L) or the duration of exposure (11-34 years) and increased frequency of structural aberrations and micronuclei in the lymphocytes of 29 male workers exposed to mercury fulminate (Anwar and Gabal 1991). From the overall results, the authors concluded that mercury in the manufacturing process may not have been the clastogen. Other genotoxicity studies are discussed in Section 2.5. 

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