Preparation method of rare earth fluoride

Abstract

The invention provides a preparation method of rare earth fluoride, and belongs to the technical field of chemical salt preparation. The method provided by the invention comprises the following steps:mixing rare earth carbonate and ammonium fluoride, then carrying out a fluorination reaction, and performing heating to remove residual ammonium fluoride to obtain rare earth fluoride, wherein the molar ratio of the rare earth carbonate to the ammonium fluoride is 1:(6-18). According to the method provided by the invention, rare earth carbonate and ammonium fluoride are used as raw materials, thepreparation process is divided into a fluorination process and an impurity removal process, rare earth carbonate is firstly fluorinated by utilizing ammonium fluoride, and then the characteristic that the decomposition temperature of the ammonium fluoride is relatively low is utilized, so that the residual ammonium fluoride is heated to be decomposed into gaseous substances to volatilize, and theaim of separating impurities from a product is further achieved. Compared with the existing dry process, the method provided by the invention has the advantages that the temperature required by the fluorination reaction is greatly reduced, the corrosivity of ammonium fluoride is lower than that of hydrogen fluoride, the manufacturing cost of used equipment is low, the ammonium fluoride decomposition product is easy to recycle, and the production cost is low.

Description

technical field [0001] The invention relates to the technical field of chemical salt preparation, in particular to a preparation method of rare earth fluoride. Background technique [0002] The traditional production process of rare earth fluoride is a wet process. Specifically, fluoride (such as hydrofluoric acid, ammonium bifluoride, etc.) is added to the rare earth compound solution, and the resulting precipitate is washed and dried to obtain rare earth fluoride. The wet process has a long production process, many impurities are introduced, and the cost is high. It also produces a large amount of fluorine-containing wastewater, and the cost of environmental protection treatment is high. In addition, rare earth oxyfluoride is easily produced during the drying process, which affects the purity of the product. Therefore, the wet production process of rare earth fluoride is gradually replaced by the dry production process. [0003] The existing dry production process uses hy...

AI Technical Summary

Problems solved by technology

Dry production of rare earth fluoride has the advantages of short process flow, high fluorination rate, difficulty in producing rare earth oxyfluoride, and high product purity, but it needs to be carried out at high temperature (generally higher than 600°C), and the material resistant to hydrogen fluoride gas under high temperature conditions High cost, fast consumption, and high price of hydrogen fluoride gas, resulting in high cost of dry production process

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