Detonation Performance And Application Of A New Emulsion Explosive Containing Common Clay

As one of the important components of industrial explosives,emulsion explosives are widely studied and used in the fields of mine metallurgy,controlled blasting etc.Specifically,in order to obtain some expected detonation parameters,operators often need to add some additives,including inert thinner,density regulator etc,for some special fields,like the explosion welding,explosion spraying etc.Unfortunately,all of these additives have their own defects.In order to take the place of traditional emulsion explosives with different drawbacks,this paper introduces a new cleaner emulsion explosive which adds common clay(never been used before in the civil explosive field)as the inert additive.After that,the detonation velocity,explosive brisance and underwater explosion experiments are performed to figure out how the content,particle of common clay and storage time effect its detonation performance.Results show that when the mass fraction of clay particles is between 0?20%,and the mass fraction of glass micro-spheres is between 5%?15%,the new explosive's detonation speed and explosive brisance can be calculated as follows:D=4923.1-99.3×a-29.8×6(m/s)and ?h=23.3-0.74×a-0.20×b(mm),respectively,where the a and b represent the mass fraction of HGM and common clay.From underwater tests,we also know that when the mass fraction of common clay increases to 20%,the peak over-pressure,impulse,specific shock energy,specific bubble energy and specific total energy of the new emulsion explosive decrease by 33.34%,13.19%,67.67%,71.73%and 70.96%,respectively.With respect to the propagation mechanism of the new emulsion explosives,clay particles and redundant glass micro-spheres both play the role of inert additives.And the mechanism of decreasing detonation speed of the new emulsion explosive can be explained from blocking effect and absorption effect.In other words,the wider the width of the post-wave reaction zone,the longer the full reaction time,and the lower the detonation velocity of the new emulsion explosive.During the storage time,the detonation velocity,explosive brisance and various underwater explosion parameters of the new emulsion explosive changed remarkably,too.The formula with 10 wt.%common clay and 15 wt.%HGM has the longest storage time.Although further increasing in clay particle content can weaken the explosive performance and decrease the overall cost of proposed emulsion explosives,too many clay particles will significantly shorten its failure time.And during the storage period of the new emulsion explosive,the phenomenon that common clay can further reduce the detonation speed,explosive brisance and various underwater explosion parameters can be explained by its adsorption effect on water steam and C18H3a steam(components of the emulsion matrix).Moreover,one of the new emulsion explosive formulas(detonation velocity is about 2350 m/s)is used in the T2-copper/1060-aluminum explosive welding,and the effect of normalizing treatment on its micro-structure and mechanical properties was studied.Results show that the welding interface of T2-copper/1060-aluminum presents a regular wavy bonding,with amplitude and period of about 45 ?m and 200?m,respectively.Besides,Al2Cu and AlCu phases are identified near the bonding interface of Cu-Al explosively-welded composites.The normalizing treatment facilitates the diffusion of elements at the bonding interface of T2/1060 composites.The longer the normalizing treatment time,the thicker and more uniform the diffusion layer thickness.The normalizing treatment also has a remarkable effect on the mechanical properties of T2/1060 explosively-welded plate.After normalizing,the micro-hardness,tensile strength and yield strain of the sample at the bonding interface changes from 215 HV,255.7 MPa and 3.64%to 170 HV,228.8 MPa and 22.4%,respectively,which means the hardness and tensile strength of the composite decrease,and the tough ness increases after the normalizing treatment.