Mercury Fulminate

MERCURY FULMINATE, Hg(CNO)₂, the salt of fulminic acid. Mercury fulminate serves as a detonator for other explosives and is used on a wide scale. It is produced in small quantities at military plants. - Course of production of mercury fulminate. In small glass flasks, one part of metallic mercury is dissolved in 12 parts of nitric acid; this solution is then poured into a glass flask filled with 10 parts of 90% alcohol. During the first operation, nitrogen oxides are released; during the second, a large amount of various vapors (CO₂, HNO₃, acetic acid, ethyl acetate, volatile cyanide compounds). The heavy white crystals of mercury fulminate precipitating during the second operation are filtered and washed with water until even traces of acid are completely removed. The wet mercury fulminate is dried, after which it is transferred to assembly workshops, where explosive caps are filled with it (alone or in combination with other substances). Wet mercury fulminate is safe, whereas dry mercury fulminate detonates upon any mechanical impacts (friction, blow, drop, knock, from an electric spark, etc.). There have been many reports in the literature about mercury poisoning among workers in this industry. Studies by Koelsch and Ilzhofer in 1919 showed that neither acute nor chronic mercury poisoning is observed among workers in the actual production of mercury fulminate (which is explained by the good design of modern workshops). In workers, especially those engaged in the first two processes, black staining of the teeth and destruction of the front teeth, mainly the incisors, were found. Koelsch considers the latter to be the result of the action of HNO₃ vapors, while he explains the black coloration by the deposition of mercuric sulfide on the teeth (the effect of hydrogen sulfide formed in the mouth on mercury). Furthermore, workers frequently experience erythema and exanthema. These lesions are so frequent, and the sensitivity of workers to them is so great, that out of newly arriving workers, only 1/4 to 1/3 can remain at work. Skin lesions appear on uncovered parts of the body in the form of a sharply itching erythema with strong edematous swelling, especially of the face and eyelids; subsequently, nodules, vesicles, and pustules form. Healing (with peeling) occurs after 1-2 weeks, and relapses are very frequent. Workers engaged with the dry substance—during sifting, drying, mixing, weighing, and filling caps—fall ill more often. The disease is observed more frequently in the summer months (sweating). In the assembly workshops, minor explosions resulting from the slightest mechanical blow are very frequent, during which a certain amount of mercury vapors is formed (without poisoning). Cases of mild mercury poisoning have been described in workers engaged in disassembling caps and in shooting in enclosed spaces. - Preventive measures: large, bright, well-ventilated rooms. The first two operations must be conducted in closed cabinets equipped with strong exhaust ventilation. Strict personal hygiene (special care of the oral cavity, frequent showers, baths). Careful selection of workers and constant monitoring of their health status. Reduction of the working day (according to the legislation of the USSR, workers in the production of mercury fulminate work 6 hours, enjoy additional leave, and receive a bottle of milk per day). To prevent large explosions, there are rules for the construction of buildings, workshops, workstations, the course of the production process, labor regime, etc.

Figure 1. Rattler of a snake from the outside (1) and in longitudinal section (2).