Experimental Study On Energy Dissipation And Failure Mechanism Of Magnetite Ore Under Impact Loading

With the construction of ecological civilization in mines in China,enterprises are required to carry out green development and industrial transformation.However,in iron ore crush process of metal mines,there is a huge problem of energy consumption,which hinders transformation and upgrading of mines seriously.Through the impact crush test of ore specimens under different working conditions,energy dissipation pattern and failure mechanism of ore were studied systematically.The main findings are as follows:1)When the dip angle is 60°,actual failure angle coincides with shear angle of the coulomb criterion basically.Ore shows shear-slip failure along stratified bedding plane,dynamic strength is minimum,absorption energy is lowest.At other angles,ore shows a mixed failure mode of split and shear-slip,with higher strength and absorption energy.2)When total input energy is constant,compared with single-stage crush,the ore treated by multi-stage crushing has higher energy utilization ratio and heavier crushing degree.In multistage crushing,the method of “high?middle?low” is adopted in turn,which can improve the energy utilization rate and achieve higher crush effect effectively.3)From wave mechanics,the stress wave at free surface of ore produces axial crack after superimposed collision,elastic strain energy at the end of ore releases the ring crack,the failure degree is high at intersection of two free surfaces.Tensile wave causes spallation at free surface of ore.The impact failure model of ore is established.4)With increase of total work or the bedding dip angle,The brittle fracture of ore,which is dominated by intergranular crack and transgranular crack a little,is transformed into ductile fracture with both transgranular fracture and lamellar tear gradually.The energy consumption mode increases gradually and degree of broken deepens.Based on the impact crush test of ore,dynamic strength,failure process,energy dissipation,fragment distribution,macro and microscopic failure mechanism of ore are studied.It has a reference value for energy consumption control in crush magnetite ore.Figure 72;Table 11;Reference 85.