Frozen nitroglycerin

A very dangerous fire hazard when exposed to heat, flame, or by spontaneous chemical reaction. A severe explosion hazard when shocked or exposed to O3, heat, or flame. Nitroglycerin is a powerful explosive, very sensitive to mechanical shock, heat, or UV radiation. Small quantities of it can readily be detonated by a hammer blow on a hard surface, particularly when it has been absorbed in filter paper. It explodes when heated to 215°C. Frozen nitroglycerin is somewhat less sensitive than the liquid. However, a half-thawed or partially thawed mixture is more sensitive than either one. When heated to decomposition it emits toxic fumes of NOx. 

Explosives with nitroglycerine should be protected from Irce/ing and the thaw ing of frozen nitroglycerine can cause disasters ( ol. Ill, p. 518). Currently in most countnes a non-freezing mixture of nitroglycerine with nitroglycol is used. The change of explosive properties on storage w as discussed in Vol. Ill, pp.436 438. 

Frozen (that is entirely, not partly, frozen) dynamite is less sensitive to blow, shock, shot, and heat than non-frozen dynamite. The reasons for this are of course the same as in the case of frozen nitroglycerine. 

Frozen pure nitroglycerin (52° F) is relatively insensitive and easily kept froz g... 

All straight nitroglycerin explosives can be frozen. Straight dynamite when frozen becomes less sensitive to shock and to initiation, but blasting gelatin becomes slightly more sensitive. 

Unlike nitroglycerin, blasting gelatin takes fire easily from a flame or from the spark of a fuse. Its combustion is rapid and violent, and is accompanied by a hissing sound. If a large quantity is burning, the combustion is likely to become an explosion, and the same result is likely to follow if even a small quantity of the frozen material is set on fire. 

Nitroglycerine may freeze at +10 °C (50°F). The frozen cartridges are unsafe to handle, because improvised thawing operations are risky. Freezing is prevented by adding nitroglycol to the nitroglycerine. 

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