Preparation method of rare earth fluoride

Abstract

The invention discloses a preparation method of rare earth fluoride. The preparation method comprises the following steps: dissolving salt containing rare earth elements into a hydroxyl ether solvent;carrying out ultrasonic treatment for 3-15 minutes to obtain a uniform solution; adding liquid containing fluorine ions into the uniform solution and uniformly mixing to obtain turbid liquid containing rare earth fluoride; extracting precipitate in the turbid liquid; and vacuum-drying the precipitate at the temperature of 60-100 DEG C for 1 h or longer to obtain rare earth fluoride, wherein the water oxygen content of the rare earth fluoride is smaller than 100ppm. According to the preparation method of the rare earth fluoride provided by the embodiment of the invention, the salt containing rare earth elements is dissolved in the hydroxyl ether solvent, the viscosity of the hydroxyl ether solvent is relatively high, the rare earth fluoride is prepared in a high-viscosity environment, thereaction environment is liquid, the reaction selectivity is relatively high, and the reaction is complete. Moreover, the whole process is carried out in liquid, hydrogen fluoride is not needed, no tail gas is generated, and the reaction process is energy-saving and environment-friendly. No water is contained in the whole reaction process, and the water oxygen content of the product is low.

Description

technical field [0001] The invention relates to the field of rare earth elements, in particular to a preparation method of rare earth fluorides. Background technique [0002] There are two existing techniques for preparing rare earth fluorides: wet method and dry method. [0003] The wet process is obtained by reacting rare earth hydroxide aqueous solution or rare earth chloride aqueous solution with hydrofluoric acid. Due to the reaction between aqueous solutions, the rare earth fluoride prepared by this process is easy to form compounds such as crystal water, resulting in the prepared rare earth Fluoride impurities have high water and oxygen content; if rare earth oxides are used as raw materials, an acid-dissolving step is added, which is easy to introduce additional impurities, high water and oxygen content, and the process is long and the amount of wastewater treated is large. Rare earth fluorides usually obtained by wet process have oxygen content above 3000ppm and hi...

AI Technical Summary

Problems solved by technology

[0004] There are two common dry processes, one is obtained by the reaction of hydrogen fluoride and rare earth oxides, but the hydrogen fluoride tail gas produced by this method is more difficult to treat

If the exhaust gas is not treated cleanly, it will cause danger to people

Another dry process is to use ammonium bifluoride to react with rare earth oxides. This method is a solid-solid reaction. On the one hand, there will be problems of incomplete reaction. On the other hand, there will be deamination and dehydration treatment, and the steps are more complicated.

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