Mechanism and method of purification and regeneration of scrap metal by rotatinal segregation
Aiming at the problems of long process,low efficiency and slow mass transfer of traditional waste metal recovery methods,the mechanism of enhanced removal of impurities in rotational segregation process was studied by means of water model experiment,which provided a dynamic basis for recycling waste metal by rotational segregation technology.The flow field visualization and velocity measurement were used to analyze the transport of solute in waste metal melt,and it was found that the rotational segregation technology can effectively improve the mass transfer efficiency of impurity atoms in the melt and reduce the mass transfer resistance of impurities at the growth interface.The results of the water model experiment show that the circulation motion mode of the flow field in the rotational segregation furnace is conducive to the movement of impurities away from the growth interface,but the circulation flow is weak at low rotational speed.The exclusion ability of impurities increases with the increase of rotational speed.However,when the rotational speed increases to 800 r/min,the impurities cannot be effectively transported to the far crystallizer end,which is not conducive to the removal of impurities.The average flow velocity increases with the increase of the crystallizer speed.When the crystallizer speed increases from 200 r/min to 800 r/min,the average flow velocity at each point increases by 2 times.The average flow velocity of the flow field increased with the increase of the immersion depth of the crystallizer.When the speed of the crystallizer was 200 r/min,the flow velocity near the liquid surface of the crystallizer increased from 0.02 m/s to 0.04 m/s with the immersion depth of the crystallizer increasing by 1/2 to 4/5,and the flow velocity at other measurement sites increased significantly,and the average flow velocity increased by 1 times.The average flow velocity of the flow field increased with the increase of the ratio between the diameter of the crystallizer and the diameter of the crucible.The diameter ratio increased from 1/7 to 1/2,and the average flow velocity in the flow field increased by about 4 times.Experiments show that increasing the rotation speed,the immersion depth of the mold and the diameter ratio of the mold to the crucible can improve the rotation driving force,thus improving the transfer rate of the solute in the melt and efficient uniform concentration field.In this study,when the diameter ratio of the crystallizer to the crucible is 1/3 and the immersion depth of the crystallizer is 4/5,it has a good effect on the transport of impurities and the uniformity of the concentration field,which is conducive to the effective removal of impurities in the rotatonal segregation process.The results show that the removal efficiency of Pb can reach 66％when the crystallizer speed is 400 r/min.This proves that rotational segregation recovery of waste metal resources can solve the problems of long process and low efficiency of traditional recovery methods,achieve deep and efficient removal of metal impurities,and meet the needs of high-value recovery of metal resources.
non-ferrous metal regenerationseparation of impuritieswater physical modelenhanced mass transfer
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维普
