Preparation And Characterization Of Heat-resistant ANFO Explosive

High-temperature blasting is a major technical and safety bottleneck for coal resource exploitation in the fire zone.While thousands of tons of explosives are demanded in fire zone blasting each year,there are no specialized heat-resistant civilian explosives and related blasting technologies yet in China.To meet the engineering blasting needs,improve the safety of blasting operation in high temperature fire area and promote the blasting efficiency,a heat-resistant porous prilled ammonium nitrate fuel oil explosive(ANFO)with good explosive power was initially designed by adding thermal decomposition inhibitors and inert substances.In this paper,the effects of various additives on the thermal decomposition of ANFO were analyzed by C80 micro calorimeter,large-dose constant temperature oven thermal analysis test,high-temperature blast hole simulation test,explosion property calculation and test.The formula of the heat-resistant ANFO was initially determined;the heat resistance and rock breaking ability of explosive was verified on site blasting operation in a coal mine with high temperature overburdens.The following conclusions were obtained:(1)Through theoretical analysis and experimental verification,the thermal safety of ANFO is obviously higher than that of emulsion explosive,and ANFO should be the main used in high temperature overburdens blasting.(2)The addition of polyamine,ammonium sulfate,sodium sulfate and marble powder could significantly improve the heat resistance of ANFO,the order was marble>polyamine>sodium sulfate>ammonium sulfate;while ammonium oxalate and dihydrogen phosphate had no obvious effect.The addition of polyamine,ammonium sulfate,sodium sulfate and marble powder could affect the explosive power of ANFO,among which marble powder had the largest impact on the explosive performance.Taken together,polyamine,ammonium sulfate,and sodium sulfate could be selected as thermal decomposition inhibitors for heat-resistant ANFO.(3)Through deep-hole loose blasting of coal mines in high temperature overburdens,the heat-resistant ANFO has obvious heat resistance effect,and the blasting rock capacity is similar to that of the ordinary ANFO.It is suitable for coal mine blasting operations and improves the operation efficiency and construction safety.(4)A new type of heat-resistant ANFO was initially designed.The formula is:porous granulated ANFO plus 4%polyamine and 3%sodium sulfate in porous granulated ANFO,the mass ratio of porous ammonium nitrate to diesel oil is 94:6.Figure[41]table[36]reference[69]...