Rare-earth ferroalloy and preparation process thereof

Abstract

The invention relates to a rare-earth ferroalloy for producing a rare-earth permanent magnetism material with high performance and a preparation process thereof. The ferroalloy comprises the contents according to the weight percentage: 30-90 of neodymium or didymium rare earth, and the balance ferrum and less than 1 of unavoidable impurities, wherein the O content is less than or equal to 0.1, the C content is less than or equal to 0.1 and the N content is less than or equal to 0.05. The alloy is prepared by an electrolytic method of fluoride molten salt system oxide, and an electrolyte of the alloy comprises rare-earth fluoride and lithium fluoride.

Description

technical field [0001] The invention relates to the field of metal materials and belongs to rare earth pyrometallurgy. Background technique [0002] Rare earths are widely used in the manufacture of various new functional materials due to their unique magnetic, optical, electrical and other superior properties, and are the basic raw materials for the preparation of rare earth functional materials. For example: NdFeB permanent magnet material occupies a very important position in the rare earth permanent magnet material. During the preparation process, rare earth metals such as Nd and Pr need to be added to obtain higher magnet coercive force and good temperature characteristics. In the preparation process of traditional NdFeB magnets, the above-mentioned single rare earth metal is directly added. Therefore, a high melting temperature is required, resulting in a large burning loss of the rare earth metal and an increase in production cost. In addition, due to the high melting...

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Problems solved by technology

This method has the following disadvantages: (1) do anode with graphite tank, graphite tank consumption is faster, can not be produced continuously, in addition, graphite tank is replaced frequently, causes current efficiency and rare earth metal yield to be low, and product quality fluctuates greatly , especially the high carbon content in the product; (2) the crucible used in this method is suspended in the molten salt, which is difficult to realize, and the patent does not provide a realization method; (3) this method is not suitable for large-scale industrialization Production

This method has the following disadvantages: (1) The raw material for electrolysis is rare earth fluoride, and rare earth fluoride must be obtained by fluorination of other compounds such as rare earth oxides, which will obviously increase the cost compared with direct electrolysis of oxides. (2) Electrolysis of rare earth Fluoride will produce a large amount of harmful gas containing fluorine, causing environmental pollution

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