Regenerated neodymium-iron-boron magnetic powder, preparation method thereof and application of regenerated neodymium-iron-boron magnetic powder in preparation of sintered magnet

Abstract

The invention provides regenerated neodymium-iron-boron magnetic powder, a preparation method thereof and application of the regenerated neodymium-iron-boron magnetic powder in preparation of a sintered magnet, and the regenerated neodymium-iron-boron magnetic powder is prepared by taking sintered neodymium-iron-boron processing oil sludge as a main raw material through the steps of pretreatment, reduction heat treatment, crushing powder preparation, powder screening and the like. The reduction heat treatment is two-stage reduction heat treatment, and flowing hydrogen is used as a reducing agent in the first-stage reduction heat treatment, so that the oxygen content in the oil sludge is reduced, and the consumption of the reducing agent in the second-stage reduction heat treatment process is reduced; at least one of rare earth elements La, Ce and Sm is used as a reducing agent in the second-stage reduction heat treatment, and the performance of the regenerated magnetic powder and the regenerated magnet cannot be remarkably influenced even if the reducing agent is not completely removed in the subsequent treatment step. According to the preparation method of the regenerated neodymium-iron-boron magnetic powder, the regenerated neodymium-iron-boron magnetic powder does not make contact with solvents such as water, methyl alcohol and ethyl alcohol any more, and a sintered magnet prepared from the regenerated neodymium-iron-boron magnetic powder has good performance.