微波场中矿物颗粒裂纹分布及演化研究

以方铅矿和方解石组成的岩石颗粒为研究对象,采用离散单元法研究了在微波照射下矿物颗粒内部裂纹扩展演化过程及其分布特征,并分析了照射时间、功率密度、能耗、矿物尺寸等的影响。结果表明,矿物裂纹主要表现为拉伸裂纹,根据分布特征及所在位置可以将其分为三类:在方解石内的扩散型裂纹、在方解石和方铅矿交界处的环形裂纹和方铅矿内裂纹,前两者的形成是微波能辅助碎矿磨矿的根本原因。其中方解石内的扩散型裂纹和交界面处的环形裂纹的形成是微波辅助碎矿和磨矿的根本原因。矿物裂纹数目随微波照射时间及能量消耗增长的曲线可以分为两类:功率密度低的为三阶段增长形式,功率密度高的为两阶段增长形式。矿物形成裂纹数目相同的情况下,随着功率密度提高,能耗降低,但高于一定值后,能耗变化不大。微波辅助方法和其他碎矿磨矿的方式类似,矿物越小越难破碎。

Research on the Crack Distribution and Evolution in Mineral Particles in Microwave Field

The crack growth and distribution characteristics of rock particles composed of galena and calcite under microwave irradiation were studied via discrete element method. The effects of irradiation time, power density, energy consumption, and mineral size were analyzed. Research results demonstrated that tension crack is dominant in minerals. Mineral cracks can be divided into three types based on distribution characteristics and locations. The diffusion crack in calcite and the annular crack at the interface are the basic mechanisms of microwave-assisted ore crushing and grinding. Mineral cracks can be categorized into types following the relationship between crack number and irradiation time and energy consumption. Mineral crack has three growth stages under low power density and two growth stages under high power density. Given the same crack number in mineral particles, energy consumption decreases with increasing power density. However, energy consumption remains basically the same after increasing power density to a certain value. Similar with other ore crushing and grinding methods, microwave-assisted method cannot easily crush small minerals.