Research on Mechanical Property Deterioration and Energy Evolution Mechanisms of Iron Ore under Microwave Irradiation

To systematically reveal the influence of laws of microwave radiation parameters (power, time) on the degradation of the mechanical properties of iron ore and the energy dissipation mechanism, and to improve the crushing efficiency of iron ore, this iron ore from Sishanling in Liaoning Province is the research object. By adopting a method combining microwave pretreatment, multi-scale mechanical tests, and microscopic tests, this thesis conducts static and dynamic impact tests as well as XRD tests on iron ore samples under different microwave actions. By analyzing the mechanical properties of iron ore subjected to various microwave treatments and utilizing the principles of energy conservation, this study elucidates the damage evolution characteristics and the laws governing energy evolution of iron ore under the coupled action of microwave and mechanical forces. The research results show that: (1) With an increase in microwave power and irradiation time, the sample mass decreases slightly, and the longitudinal wave velocity, uniaxial compressive strength, and elastic modulus exhibit a linear degradation trend. Microscopic tests have confirmed that the damage is caused by thermal stress cracking, rather than a change in composition. (2) The analysis of energy evolution indicates that microwave pretreatment diminishes the total input energy density of the sample, reduces the proportion of elastic energy, and elevates the proportion of dissipated energy. This phenomenon suggests a deterioration in the ore’s storage capacity and a transition toward plastic yielding. (3) Dynamic impact tests show that an increase in microwave damage leads to a 45.58% increase in reflected energy, a 16.12% decrease in transmitted energy, and an increase in energy dissipation to 37.49%.