Method for preparing cerium-containing rare earth permanent magnet material by adding nano metal powder into magnet steel scrap

Abstract

The invention discloses a method for preparing a cerium-containing rare earth permanent magnet material by adding nano metal powder into magnet steel scrap. The method comprises the following steps: according to the classifying standard that waste magnet steel with same batch, same model and same contained rare earth elements is classified as the same class, pre-classifying collected waste magnet steel into a pretreated magnet material; then, adding the obtained pretreated magnet material and prepared nano metal powder into a common electrolytic furnace to carry out smelting for enabling the pretreated magnet material and the prepared nano metal powder to form a molten alloy liquid; casting and cooling the molten alloy liquid to obtain alloy ingot, carrying out hydrogen-crushing and airflow milling and crushing on the alloy ingot to obtain fine powder, and carrying out static pressing, sintering and two-stage thermal treatment on the fine powder to obtain cerium-containing rare earth permanent magnet material blank; and finally, according to practical needs, carrying out mechanical processing, cutting and precision-grinding on the cerium-containing rare earth permanent magnet material blank, thereby obtaining the cerium-containing rare earth permanent magnet material. The fluorescent lifetime of the cerium-containing rare earth permanent magnet material is effectively prolonged by adding the nano metal powder; and the permanent magnet material has a relatively high activator critical concentration; and by virtue of pre-classifying, time of recycling waste magnet steel can be saved, and extraction process steps are reduced.

Description

technical field [0001] The invention relates to the technical field of rare earth permanent magnet materials, in particular to a method for preparing rare earth permanent magnet materials containing cerium by adding nanometer metal powder to magnetic steel waste. Background technique [0002] Due to the high brittleness of NdFeB magnet materials and miscellaneous specifications, problems such as missing corners and poor dimensions are prone to occur during the electroplating process; thus resulting in a very large amount of scrapped NdFeB magnets after electroplating, and due to other special requirements of customers. Lead to bad scrap phenomenon. The current recycling and reuse process for waste magnets is as follows: all the collected waste magnets are mixed together without pre-sorting, and returned to the recycling container in a unified way, and all the waste magnets contained in the waste magnets are collected in the recycling container. The rare earth elements are e...

AI Technical Summary

Problems solved by technology

However, since the above-mentioned metals are non-magnetic phases, they can only be added in a small amount, so they can only control the distribution and microstructure of the Nd-rich phase during the sintering temperature and tempering process within a small range.

On the other hand, the addition of rare earth elements such as lanthanum and cerium can reduce the sintering temperature, but the saturation magnetization of the lanthanum-iron-boron and cerium-iron-boron phases is lower than that of the neodymium-iron-boron phase, which reduces the remanence of the magnet, especially its anisotropy field Only one-third of the NdFeB phase

And its stability is poor, especially lanthanum and cerium are more active, and the ability to combine with oxygen is strong. The oxygen content in the magnet increases with the increase of lanthanum and cerium content.

However, the increase of oxygen content will easily lead to changes in the structure of the rare earth-rich phase, resulting in a further reduction in the coercive force of the magnet, making it difficult to meet the requirements of commercial magnets for comprehensive magnetic properties such as coercive force and magnetic energy product.