Effect of Low Temperature Environments on the Explosive Properties of Emulsion Explosives

The decline of explosive properties of emulsion explosives will seriously affect the blasting effect in the environment of low temperature. The study on the evolution law of explosive properties of the emulsion explosives in coordination with the temperature variation of the emulsion explosives presents a certain engineering application value. A series of precise temperature control devices for emulsion explosives were designed, and then the detonation velocity, the brisance, the working capacity and the overpressure of air shock wave were measured with various temperature of 25, 0, −5, −10 and −15 ℃. Meanwhile, the microstructure of the emulsion explosives was characterized. The experimental results showed that when the temperature of the emulsion explosives was reduced from 25 ℃ to −15 ℃, the detonation velocity of the explosive was reduced from 4227 m/s to 3291 m/s, the brisance of the explosive was reduced from 13.0 mm to 5.2 mm, the working capacity of the explosives was reduced from 323 mL to 208 mL, and the overpressure of air shock wave was reduced from 284.9 kPa to 115.8 kPa. With the decrease of the temperature of the emulsion explosives, the precipitation of ammonium nitrate crystal increased along with the partial structure failure of the emulsion particles, resulting in changes in the microstructure and declines in the explosive properties of the emulsion explosives. Low-temperature environment mostly affected the brisance of emulsion explosives, but slightly affected the detonation velocity. With the decrease of temperature, the decline amplitude of explosive properties would be accelerated. It is suggested that the design of blasting properties should be adjusted according to the decline amplitude of explosive properties.