| At present,the problem of high-temperature(fire area)blasting in open-pit coal mine is a technical and safety bottleneck.So far,there has not been much research and development of heat-resistant civil explosives and related application technologies in China.However,the annual demand for industrial explosives for high-temperature(fire area)blasting has reached a certain scale,which affects the improvement of rescue mining safety in spontaneous combustion mining areas.Therefore,considering the safety conditions of industrial explosives used in high-temperature(fire area)blasting at present,this paper adds heat-resistant inhibitor-x to ordinary emulsion explosives,appropriately adjusts the formula of emulsion explosives,and discusses the heat-resistant effect of a heat-resistant emulsion explosive in high-temperature blast holes,so as to provide appropriate feasible ideas for improving the safety and efficiency of high-temperature blasting in open-pit coal mines.In order to study the thermal safety performance of the heat-resistant emulsion explosive and make it have reliable technical parameters in blasting operation,the adiabatic thermal decomposition experiment of ordinary and heat-resistant emulsion explosive matrix is carried out by arc micro adiabatic calorimeter in this paper,the thermal decomposition kinetic parameters of two emulsion explosive matrix are obtained,and the dynamic results are calculated and analyzed to obtain the three factors of thermal decomposition kinetics,The thermal safety performance of heat-resistant emulsion explosive is discussed;According to the thermal explosion theoretical model of Semenov and frank kamenetskii,the self accelerating decomposition temperature(SADT)and explosion delay period of two kinds of emulsion explosives were calculated under the conditions of hole depth of 10 m and 15 m and hole diameter of100 mm and 200 mm respectively.By simulating the experiment of high-temperature blast hole oven,several steel cylinders with different sizes are designed.Under the high-temperature state of 250 ℃,the heat resistance of the two emulsion explosives with the length diameter ratio of the steel cylinder is explored,in order to provide appropriate guidance for the parameter design of high-temperature blast hole network in open-pit coal mine.The main conclusions of this experiment and analysis are as follows:(1)Through the arc micro adiabatic calorimeter experiment,it is found that the heat-resistant emulsion explosive matrix has higher initial decomposition temperature t0 and reaction activation energy EA than the ordinary emulsion explosive matrix,and the addition of heat-resistant inhibitor-x should not be too much.Among them,the emulsion explosive matrix with 5% X has the best heat-resistant effect,the highest tmrad value of sample reaction and higher safety factor.(2)According to the calculation results of Semenov and frank kamenetskii thermal explosion theoretical model,it is found that the temperature of heat-resistant emulsion explosive is about 50 ℃ higher than that of ordinary emulsion explosive SADT,and has good heat-resistant behavior;In the two thermal explosion models,the change of hole depth and aperture has a certain impact on SADT temperature.Among them,the change of aperture in Frank kamenetskii model is more obvious,and the calculation results are more conservative;Through the calculation of thermal explosion delay period,it is found that the critical explosion temperature of heat-resistant emulsion explosive is about 40 ℃ higher than that of ordinary emulsion explosive at the same time,which has higher heat-resistant safety expectation.(3)In the simulated high-temperature blast hole oven experiment,through the judgment of different temperature gradients,it is found that the ignition state of the emulsion explosive matrix of the two samples occurs between 200 ～ 250 ℃,but the ignition delay period of the heat-resistant emulsion explosive matrix is about 1000 s later than that of the ordinary emulsion explosive matrix;According to the high-temperature oven experiment of steel cylinder with different length diameter ratio,it is found that the larger the length diameter ratio,the shorter the ignition delay period of emulsion explosive matrix in the high-temperature oven.Therefore,it is suggested to make the value of blast hole as small as possible in the actual high-temperature blasting.Figure [16 ] Table [14] Reference [91]... |
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