The Impact of pH Value on the Performance of a Novel Ammonium Nitrate-based Explosive
Y.-A. Chen1,2, W.-Y. Huang1, G.-J. Fang1, Y.-C. Sun1, Q.-A. Wang1
1School of Chemical and Blasting Engineering, Anhui University of Science and Technology, Huainan, China
2Anhui Key Laboratory of Explosive Energy Utilization and Control, Huaibei, China
Keywords: hexamethylenetetramine (HMTA), ammonium nitrate (AN), ammonium amine explosives, pH value, detonation velocity, water resistance
Abstract
To improve inherent safety and reduce energy consumption in industrial explosives production, the water-soluble compound hexamethylenetetramine is being used to replace the traditionally used insoluble fuel oil in ammonium nitrate-based explosives. This oxidizer and fuel, combined in water, create an intermolecular explosive called an ammonium amine explosive. The effect of pH in the range of 4.0 to 5.8 on the density of this explosive, crosslinking time, microbubble formation, detonation velocity, and water resistance was determined. The studies were conducted using density measurements, a digital viscometer, an optical microscope, detonation velocity tests, and a conductivity meter. The results show that ammonium amine-based explosives prepared at various pH levels form numerous chemically sensitized microbubbles, the average diameter of which decreases as the pH decreases. Lower pH values are associated with higher foaming rates and shorter crosslinking and foaming times. The detonation velocity of ammonium amine-based explosives is 3,500-4,200 m/s, slightly lower than that of conventional emulsion explosives. Furthermore, a comparison of the water resistance of ammonium amine-based explosives with crosslinking times of 1 and 24 hours yields contrasting results. A pH of approximately 5.2 sets the boundary between in-situ mixed and packaged ammonium amine-based explosives. Packaged explosives show significant advantages at pH values above 5.2, while in-situ mixed explosives are more advantageous at lower pH values. These results provide a theoretical basis for improving the performance of this new water-resistant nitrated substance and simplify its industrial application.
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