Method for preparing high purity rare earth metal and its apparatus

Abstract

The invention relates to a method for preparing a high purity rare earth metal and its apparatus, which is characterized in that a lithium thermal reduction-vacuum distillation combined technology is used for preparing the high purity rare earth metal. The method comprises the following steps: taking rare earth chloride as a raw material and lithium metal as a reducing agent, placing in a reaction container, in a reaction system, carrying out a liquid-liquid displacement reaction of lithium metal and rare earth chloride under the inert gas protection (the pressure is 0.1-0.5 MPa) and the temperature of 850-1100 DEG C, then vacuum-pumping the reaction system to 10<-1>-10<-3> Pa, wherein the temperature is controlled at 900-1200 DEG C, evaporating lithium metal and lithium chloride, separating slag and metal to obtain the high purity rare earth metal. The reaction apparatus is composed of a furnace cover (1), a communicating pipe (2), a collector (3), a furnace body (4), a thermal baffle (5), a reactor (6), a heating device (7), an inflation system (8) and a vacuum system (9). The invention has the advantages of short process flow, high yield of rare earth metal and low production cost; the purity of the prepared rare earth metal is high. The used apparatus is simple and is easy to enlarge, and is suitable for large batch of industrial production.

Description

technical field [0001] The invention relates to a method and a device for preparing high-purity rare earth metals by a combination method of metallothermic reduction and vacuum distillation, belonging to the field of rare earth pyrometallurgy. Background technique [0002] Due to their irreplaceable excellent magnetic, optical and electrical properties, rare earths have become indispensable basic raw materials for high-tech functional materials such as magnetism, luminescence, laser, hydrogen storage, and superconductivity. They are widely used in computers, high-density information storage, and communications. , conversion, high-precision guidance, ray particle detection and recording, information highway and national security protection and other high-tech fields, such as Magneto NdFeB permanent magnets are widely used in VCM, motors, MRI and audio, etc., high specific energy Ni-MH battery materials Widely used in communications and electric vehicles, TbDyFe giant magnetos...

AI Technical Summary

Problems solved by technology

The disadvantages of this process are: 1) the removal effect of impurities other than carbon is very small, and the removal effect of carbon impurities itself is not ideal, and the purity of the metal is not high; 2) due to the use of neodymium oxide, Neodymium fluoride and calcium oxide, therefore, it is inevitable to introduce a large amount of oxygen, and because of the high melting point of neodymium oxide and calcium oxide, there will be a large amount of inclusions of neodymium oxide and calcium oxide in metal neodymium

The disadvantages of this process are: 1) rare earth metals with high purity cannot be obtained, especially the gas impurity content is high; 2) this process uses calcium chloride as an auxiliary salt bath, which will cause a large amount of chlorides to exist in the metal

The disadvantages of this process are: 1) the metal gas impurities and non-rare earth metal impurities obtained by this process have high content; 2) this process has high requirements for the purity of raw materials and related auxiliary materials, even reaching the fluorescence level

The disadvantages of this process are: 1) the metal gas impurity and non-rare earth metal impurity content obtained by this process are high, and the removal effect is not good for impurity elements such as Fe, Ni, Cu, etc. whose vapor pressure is close to the vapor pressure of metal terbium; 2 ) The absolute purity of terbium metal obtained by this process is not high, mainly because the crude terbium metal preparation process for purification is long, resulting in serious pollution of crude terbium metal

The disadvantage of this process is that the reduction process is a gas-phase reduction reaction. On the one hand, it is inevitable that a considerable part of the chloride and lithium will be taken away, or evaporated and cooled in a low temperature area and cannot react with each other, resulting in loss of raw materials; Two, at this temperature, the evaporation rate of rare earth chlorides is low, and the chlorides cannot be completely evaporated into a gaseous state in a short period of time, and the gas phase reduction reaction takes a long time, which makes this method take a long time, consume high energy, and have low production efficiency.

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