Method for preparing rare earth fluoride by taking rare earth oxide as raw material

Abstract

The invention relates to a method for preparing rare earth fluoride by taking rare earth oxide as a raw material, which comprises the steps of: (1) mixing the rare earth oxide with water, and adding concentrated hydrochloric acid into the mixture to generate rare earth chloride solution; (2) increasing the temperature of the rare earth chloride solution to be between 70 and 90 DEG C, adding a precipitator into the rare earth chloride solution, and performing thermal insulation for 10 to 30 minutes; (3) adding hydrofluoric acid into a reaction liquid, and performing a fluoridation reaction for 5 to 30 minutes at a temperature of between 70 and 90 DEG C until the reaction is complete; and (4) obtaining the rare earth fluoride by a precipitate generated by the reaction through washing, settlement, filtration and drying. The method ensures that the formed rare earth fluoride has large particles and is easy to filter, wash and precipitate after the precipitator, namely propane diacid is added, and effectively overcomes the disadvantages that the rare earth fluoride is easy for penetration filtration and is difficult to precipitate in the prior art; a fluorination endpoint determination method is adopted, which avoids the various problems caused by adding excessive hydrofluoric acid; and at the same time, mother solution containing hydrochloric acid can be circularly used, which has less discharge of waste liquid and is favorable for environmental protection.

Description

technical field

[0001] The invention relates to a preparation method of rare earth fluorides, in particular to a method for preparing rare earth fluorides by using rare earth oxides as raw materials. Background technique

[0002] my country is rich in rare earth resources, and various rare earth products are widely used in many industries. Among them, rare earth fluorides are important raw materials and electrolytes for the production of rare earth metals by metallothermic reduction, and are also additives for steel and nonferrous metals. They are also used in special optical fibers, lasers, etc. It is also widely used in new functional materials such as materials, and is also used as an additive for ceramics and glass.

[0003] The preparation of rare earth fluorides is divided into dry process and wet process. The dry process is a gas-solid phase fluorination reaction between hydrogen fluoride gas and rare earth oxides at high temperature to directly generate solid rare ear...