The present disclosure provides a sintered neodymium-iron-boron permanent magnet, a preparation method and use thereof. The permanent magnet described herein comprises a grain and a grain boundary phase. The grain boundary phase is located on an epitaxial layer of the grain. The grain boundary phase comprises at least an RH. The grain comprises at least Nd.sub.2Fe.sub.14B. In the grain boundary phase within a depth of 100 ?m from the surface to the center of the sintered neodymium-iron-boron permanent magnet, the area of the grain boundary phase with an RH content of more than 6 wt % accounts for 50% or more of the total area of the grain boundary phase. The present disclosure adopts an RH and an RL as the diffusion source for composite diffusion, significantly improving the coercivity of the permanent magnet and the utilization rate of the RH in the diffusion source.

A rare earth permanent magnet, and a preparation method therefor are provided. The rare earth permanent magnet M and the preparation method may effectively improve the grain boundary anisotropy of the magnet, provide more diffusion channels through which a heavy rare earth diffusion source can enter the inside of the magnet, such that the heavy rare earth diffusion source is more effectively diffused into the magnet, the intrinsic coercivity of the magnet is greatly improved, and a magnet N having high intrinsic coercivity is obtained. Using the same amount of a heavy rare earth diffusion source material, the method produces magnet N having high intrinsic coercivity amplification with reduced production costs.

A metal power recycling system has at least one chamber into which metal scraps are placed, at least one transmission line enabling metal scraps to be transferred out of the chamber, at least one pretreatment unit into which the metal scraps are transferred through the transmission line and in which oxygen removal, hydrogenation, cooling, grinding and sieving processes are performed for the metal scraps, at least one gathering chamber into which the sieved powder-form metal scraps are transferred from the pretreatment unit through the transmission line is disclosed.

The present disclosure discloses a cerium-added RE-T-B-M series sintered neodymium-iron-boron magnet, which relates to the technical field of neodymium-iron-boron permanent magnets, the structure of the magnet contains a RE.sub.2Fe.sub.14B main phase, a RE-rich phase, a REFe.sub.2 phase, and a sandwich grain boundary phase, wherein the sandwich grain boundary phase includes a RE-rich phase, a Fe-rich phase, and a REFe.sub.2 phase, and in the sandwich grain boundary phase, starting from the side near the grains of RE.sub.2Fe.sub.14B main phase, the first layer is the RE-rich phase, the second layer is the Fe-rich phase, and the third layer is the REFe.sub.2 phase, where RE includes cerium element and at least one of other rare earth elements, and the cerium element accounts for 3.0-15.0% by mass of the total elements, T is iron element and cobalt element, B is boron element, and M is Al, Cu, Ga, and Ti elements. A cerium-added RE-T-B-M series sintered neodymium-iron-boron magnet according to the present disclosure can alleviate the negative effects on the magnet due to the addition of cerium element.

A method of processing NdFeB magnetic powder comprises: providing a source of hydrogenated NdFeB powder (101, 102, 103); feeding said powder into an inlet of a cyclone separator (104); separating the powder into an overflow enriched in Nd-rich grain boundary phase and an underflow enriched in Nd.sub.xFe.sub.yBH.sub.z matrix phase particles (106); optionally feeding the underflow back into the inlet of the cyclone separator whereby to further enrich the underflow in the Nd.sub.xFe.sub.yBH.sub.z matrix phase particles (108a); and collecting the underflow (108).

There is provided a method for manufacturing a rare earth sintered magnet by many times repetitively finely pulverizing a rare earth alloy on a jet mill by supplying high-pressure nitrogen gas to narrow grain size distribution to make an easy alignment in a magnetic field, and by micronizing crystal grains by using a hydrogenation-disproportionation-desorption-recombination (HDDR) process, to improve the coercivity and thermostability of the rare earth sintered magnet.

There is provided a method for manufacturing a rare earth sintered magnet by many times repetitively finely pulverizing a rare earth alloy on a jet mill by supplying high-pressure nitrogen gas to narrow grain size distribution to make an easy alignment in a magnetic field, and by micronizing crystal grains by using a hydrogenation-disproportionation-desorption-recombination (HDDR) process, to improve the coercivity and thermostability of the rare earth sintered magnet.

The invention relates to a body (2), at least one mill (3) located on the body (2) so as to rotate about its axis, more than one ball (b) being located in said mill (3), said balls (b) acting on a material to be ground (m) therein by exerting frictional and impact forces on the material to be ground (m) so that the material to be ground (m) is brought to a pulverized form.

The invention relates to a body (2), at least one mill (3) located on the body (2) so as to rotate about its axis, more than one ball (b) being located in said mill (3), said balls (b) acting on a material to be ground (m) therein by exerting frictional and impact forces on the material to be ground (m) so that the material to be ground (m) is brought to a pulverized form.

To provide a rare earth magnet ensuring excellent magnetic anisotropy while reducing the amount of Nd, etc., and a manufacturing method thereof.

A rare earth magnet comprising a crystal grain having an overall composition of (R2.sub.(1-x)R1.sub.x).sub.yFe.sub.100-y-w-z-vCo.sub.wB.sub.zTM.sub.v (wherein R2 is at least one of Nd, Pr, Dy and Tb, R1 is an alloy of at least one or two or more of Ce, La, Gd, Y and Sc, TM is at least one of Ga, Al, Cu, Au, Ag, Zn, In and Mn, 0<x<1, y=12 to 20, z=5.6 to 6.5, w=0 to 8, and v=0 to 2), wherein the average grain size of the crystal grain is 1,000 nm or less, the crystal grain consists of a core and an outer shell, the core has a composition of R1 that is richer than R2, and the outer shell has a composition of R2 that is richer than R1.