Study On The Influences Of The Crystalline Sodium Nitrite On Thermal Stability Of Emulsion Explosive

In order to study the influences of the crystalline sodium nitrite on thermal stability of ammonium nitrate (AN), ammonium nitrate emulsion (ANE) and emulsion explosive (EE), Differential Scanning Calorimeter (DSC), Accelerating Rate Calorimeter (ARC) and Modified Vent Pipe Test (MVPT) were used to investigate the thermal decomposition processes of AN, ANE and EE. At the same time, thermal stabilities of these three samples affected by crystalline sodium nitrite were carried out according to "Thermal stability test for ammonium nitrate emulsions, suspensions or gels".The test results indicated that, in small-scale tests (DSC and ARC), the initial decomposition temperatures of AN, ANE and EE were 203.67℃,243.13℃ and 224.02℃ in DSC, respectively; while they were 245.62℃,245.56℃ and 215.58℃ in ARC; in large-scale test (MVPT), significant thermal decomposition temperatures of AN, ANE and EE occurred at 150℃,173℃ and 160℃. These mean that the mass of the samples had a significant influence on the thermal decomposition characteristic, the larger the mass of the samples, the lower the temperatures of decomposition.Thermal stabilities of the mixed systems of AN, ANE and EE with crystalline sodium nitrite (10 g) in different environmental temperatures showed that there happened obvious exothermic reactions at 45℃ and 50℃ in mixed systems of AN and EE with 10 g crystalline sodium nitrite, while the system of ANE and sodium nitrite remained stable within 100℃. With the water content in samples increasing, the critical temperatures of vigorous reaction with crystalline sodium nitrite increase.The critical additions of crystalline sodium nitrite in AN, ANE and EE in critical temperature were 1 g,10 g,2 g, the higher the water content in samples, the larger the additions of crystalline sodium nitrite.