Method for producing praseodymium neodymium fluoride from fluorine-containing wastewater

Abstract

The invention discloses a method for producing praseodymium neodymium fluoride from fluorine-containing wastewater. The method comprises the following steps of: S1, regulating the pH value of fluorine-containing wastewater mother liquor to 5-9 by using acid, adding a soluble calcium salt into the fluorine-containing wastewater mother liquor to react, filtering the fluorine-containing wastewater mother liquor after the reaction is ended, and removing the filter residue; S2, adjusting the acidity of the fluorine-containing wastewater mother liquor obtained in S1 to 0.1+ / -0.05mol / L by using acid,adding the fluorine-containing wastewater mother liquor serving as a precipitator into the pulpified praseodymium-neodymium carbonate mixed solution, and keeping the pH value of the whole solution system at or below 2.0 during mixing reaction; S3, after the reaction is completed, performing filtering to obtain the filter residue, and performing subsequent treatment on the filter residue to obtaina praseodymium neodymium fluoride product. Fluorine-containing wastewater generated in bastnaesite hydrometallurgy is used as the raw material and auxiliary material for producing praseodymium neodymium fluoride, so that the problem of high cost for producing praseodymium neodymium fluoride can be solved, fluorine resources in the fluorine-containing wastewater can be recycled, and the defects ofthe existing praseodymium neodymium fluoride production process are overcome.

Description

Technical field [0001] The invention relates to the technical field of the production of neodymium praseodymium fluoride, in particular to a method for producing neodymium praseodymium fluoride by using fluorine-containing wastewater. Background technique [0002] Rare earth fluoride is an important raw material for the preparation of rare earth metals and alloys by the oxide electrolysis method and the calcium thermal reduction method. For the praseodymium neodymium alloy, the praseodymium neodymium fluoride is used as the raw material of the electrolytic metal to produce the praseodymium neodymium alloy. There are three production processes for neodymium praseodymium: one is the hydrofluoric acid method (wet method) made from neodymium praseodymium carbonate and hydrofluoric acid; the other is the ammonia hydrogen fluoride method (dry method) made from ammonium bifluoride and neodymium praseodymium oxide. ; The third is the hydrogen fluoride gas method (gas method) obtained by ...

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Problems solved by technology

[0005] The purpose of the present invention is to provide a method for producing praseodymium-neodymium fluoride from fluorine-containing waste water mainly aiming at the high cost problem existing in the production of praseodymium-neodymium fluoride. The fluorine-containing wastewater is used as the raw and auxiliary materials for the production of NdPrF, which can not only solve the problem of high cost of producing NdPrF, but also recover the fluorine resources in the wastewater containing fluorine, reducing the cost of bastnaesite wet smelting. Reduce the cost of fluorine-containing wastewater treatment, and at the same time solve the problems existing in the existing production process of praseodymium and neodymium fluoride and bastnaesite hydrometallurgy process

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