Study On The Effect Of Tracer On The Performance Of Chemically Sensitized Emulsified Explosives And Its Tracer Sensitivity

Explosives are widely used in aerospace,military confrontation,mining and building demolition.With the popularity of common explosives formulations,coupled with relatively simple production methods,they pose a great threat to world public safety,so whether explosives can be detected quickly,accurately and safely has been a long-standing issue of widespread concern in all walks of life.In this paper,a certain rare earth element oxide with excellent stability as a tracer marker for explosives（hereinafter referred to as tracer）is added to the most commonly used industrial explosives-emulsion explosives,and a series of experimental studies are conducted.In order to study the influence of tracer on the performance of chemically sensitized emulsion explosives and the sensitivity of the security check,0%,1%,3%,5%mass fraction of tracer was added in the preparation of chemically sensitized emulsion explosives and labeled as 1#,2#,3#and 4#samples,and the explosive performance and thermal decomposition tests were carried out on each sample,mainly including:explosion velocity test,slamming test,spherical packet aerial explosion test and iron plate test;using STA synchronous thermal analyzer and C80 microcalorimeter,thermal weight loss（TG）test and microcalorimetry test were carried out on four sample matrices at different heating rates.The emulsified explosives added with 0.05%tracer were wrapped and blocked using common materials such as foam board,plastic film and luggage,and the tracer sensitivity detection experiments were conducted by X-ray fluorescence spectrometer with different excitation voltages and currents.The main conclusions of the experiments are as follows:（1）The addition of a few tracers did not significantly affect the microstructure,blast performance and thermal susceptibility of the chemically sensitized emulsified explosives.With the increase of tracer content,the number and size of sensitization bubbles in the microstructure of chemically sensitized emulsion explosives did not change significantly,and the observed bubbles were all below 100μm in diameter,which were all effective sensitization bubbles that could form hot spots.compared to 1#,2#of the lead column compression decreased by 1.115 mm,burst speed increased by 44m/s;3#of the lead column compression decreased by 0.581 mm,burst speed increased by 143 m/s;4#of the lead column compression decreased by 0.45 mm,burst speed increased by 56 m/s.The addition of 1%,3%,5%tracer of the sample emulsion explosives compared to the non-tracer samples of its.Comparedwith 1#samples,2#samples of lead column compression decreased by 1.115 mm,burst speed increased by44 m/s;3#samples of lead column compression decreased by 0.581 mm,burst speed increased by 143 m/s;4#samples of lead column compression decreased by 0.45 mm,burst speed increased by 56 m/s.2#,3#,4#samples compared to 1#samples,the peak overpressure of the air explosion in turn decreased by 3.2%,2.9%and 5.4%,in 200℃constant temperature heating,the four samples did not appear burning or explosion phenomenon,showing a positive sense.（2）The thermo-weight loss curves of all 4 emulsified explosive matrix samples could be classified into three phases with the same trend.By performing TG-DTG analysis on four specimens at the same temperature rise rate,the DTG peak temperature difference value?Tmax was merely 5.3℃.As the tracer content increased from 0%to 5%,the kinetic mechanism function of the specimens changed from a one-dimensional diffusion model to a three-dimensional diffusion model.The C80 heat flow curves of the four emulsified explosive matrix specimens showed a consistent trend,showing a sharp exothermic peak at about 270℃ and increasing until the peak was reached.Combined with the RRI calculation,the results showed that the reactivity risk index of specimens 1^#-4^#showed an overall decreasing trend.（3）The characteristic X-ray fluorescence of the tracer has good penetration and can be detected accurately.In the same coating medium,the Net Rate,Net Area,Gross Area and other parameters gradually increased with the increase of voltage value under the same excitation current condition;the fluorescence intensity increased continuously with the increase of excitation current,and compared with the blank control group,the fluorescence intensity of the experimental group with blocking medium increased significantly.Comparing the count rates,it is concluded that the tracer contained in the emulsion explosives can be effectively detected in the range of excitation energy of 15.4-17.9 keV and 19.27-202.22 keV,and the most optimal excitation energy is 17.3824keV.