Science and Technology of Energetic Materials

Vol.75, No.1 (2014)

Research paper

Thermal hazard evaluation of ammonium nitrate emulsions by DSC and 1.5 L pressure vessel test
Ken Okada, Ai Funakoshi, Miyako Akiyoshi, Shu Usuba, and Takehiro Matsunaga


Bulk emulsion explosives have been generally used for blasting systems in many countries but not in Japan. As ammonium nitrate emulsion (ANE) is sensitized as an explosive precursor only at the time of use, its thermal hazard evaluation during the storage and the transportation is essentially important ; ANE is composed of ammonium nitrate, water, oil and emulsifier. For evaluation of its thermal stability, 1.5 L pressure vessel tests (1.5L-PVT) have been newly developed in the present work as a testing method on an intermediate scale. The vessel of the 1.5L-PVT is composed of a thermocouple, a pressure sensor, an orifice plate and a bursting disk. Some kinds of ANEs with different water contents have been prepared. The ANEs of 100 g order have been heated by gas burners, and the temperature and the pressure have been measured simultaneously. The bursting disk is adjusted to relieve the pressure above 2MPa. In the case of 1.5 L-PVT, orifice blocking is fully expected not to occur so readily as in the current Koenen test. The DSC before 1.5L-PVT has also supplied useful information as a screening test. The water contents of the ANEs are found to be one of the key factors for reducing a probability of thermal hazard.

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ammonium nitrate emulsion, thermal hazard evaluation, DSC, 1.5 L-pressure vessel test

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