Discrete element method （DEM） has been used to investigate the effects of particle elastic modulus and coefficient of inter-particle sliding friction on milling of mineral particles. An autogeneous mill of 600 mm di...Discrete element method （DEM） has been used to investigate the effects of particle elastic modulus and coefficient of inter-particle sliding friction on milling of mineral particles. An autogeneous mill of 600 mm diameter and 320 mm length with 14,500 particles has been selected for the simulation. Various mill performance parameters, for example, particle trajectories, collision frequency, collision energy and mill power have been evaluated to understand the effects of particle elastic modulus and inter-particle sliding friction during milling of particles. For the given model, it has been concluded that at high energy range, as the elastic modulus and particle sliding friction increase the energy dissipated among the particles increases. The collision frequency increases with the increase in elastic modulus, however, this trend is not clearly observed with increasing inter-particle sliding friction. The power draw of the mill increases with the increase in fraction of mill critical speed.展开更多
Internal friction and modulus measurements of nano ZrO_2 solids for different particle sizes (including original compacted and annealed samples) were systematically carried out from room temperature to -200℃. It was ...Internal friction and modulus measurements of nano ZrO_2 solids for different particle sizes (including original compacted and annealed samples) were systematically carried out from room temperature to -200℃. It was found that the three peaks (P_1, P_2 and P_3 corresponding to ascending measurement, or P_1~', P_2~' and P_3~' corresponding to descending measurement) appeared. By investigating the behavior of internal friction peaks (P_1, P_2, P_3 orP_1~' P_2~', P_3~'), it is indicated that the origin of peak P_3 or P_3~' can be attributed to grain boundary relaxation, that is, it is caused by slip of the grain boundaries in nano ZrO_2 solids. The peak P_2 (or P_2~')and P_1 (or P_1~') may possibly be associated with phase transformation of nano ZrO_2 solids at low temperature range. The energy dispersion decreases and the modulus increases notably with the increase in annealing temperature of the nano samples.展开更多
文摘Discrete element method （DEM） has been used to investigate the effects of particle elastic modulus and coefficient of inter-particle sliding friction on milling of mineral particles. An autogeneous mill of 600 mm diameter and 320 mm length with 14,500 particles has been selected for the simulation. Various mill performance parameters, for example, particle trajectories, collision frequency, collision energy and mill power have been evaluated to understand the effects of particle elastic modulus and inter-particle sliding friction during milling of particles. For the given model, it has been concluded that at high energy range, as the elastic modulus and particle sliding friction increase the energy dissipated among the particles increases. The collision frequency increases with the increase in elastic modulus, however, this trend is not clearly observed with increasing inter-particle sliding friction. The power draw of the mill increases with the increase in fraction of mill critical speed.
基金Project supported by Laboratory of Internal Friction and Defects in Solids, Academia Sinica
文摘Internal friction and modulus measurements of nano ZrO_2 solids for different particle sizes (including original compacted and annealed samples) were systematically carried out from room temperature to -200℃. It was found that the three peaks (P_1, P_2 and P_3 corresponding to ascending measurement, or P_1~', P_2~' and P_3~' corresponding to descending measurement) appeared. By investigating the behavior of internal friction peaks (P_1, P_2, P_3 orP_1~' P_2~', P_3~'), it is indicated that the origin of peak P_3 or P_3~' can be attributed to grain boundary relaxation, that is, it is caused by slip of the grain boundaries in nano ZrO_2 solids. The peak P_2 (or P_2~')and P_1 (or P_1~') may possibly be associated with phase transformation of nano ZrO_2 solids at low temperature range. The energy dispersion decreases and the modulus increases notably with the increase in annealing temperature of the nano samples.
