Process for extracting and separating rare-earth elements

Abstract

The invention provides a process for extracting and separating rare-earth elements. In the process, acid organic extracting agents such as P507, P204, C272 and naphthenic acid, aqueous solution of organic acid salt of magnesium and / or calcium, and rare-earth solution are mixed for pre-extraction; rare earth ions are extracted into an organic phase; and the organic phase is clarified to form a rare earth ion loaded organic phase used for extracting and separating mixed rare earth feed liquor. A single rare-earth compound or a concentrate of several rare-earth elements is obtained through multi-stage extraction-washing-back extraction. The aqueous solution of organic acid salt of magnesium and / or calcium is prepared by roasting minerals such as magnesite, limestone, calcite and dolomite and dissolving with organic acid; the contents of impurities such as silicon, iron and aluminium are low; three-phase substances are not generated in the pre-extraction and extraction and separation processes; the purity of rare earth products is not influenced; the organic phase is not subjected to ammonia saponification, and ammonia nitrogen wastewater is not generated; the production cost of the rare earth products is greatly reduced; and a great amount of three-waste treatment cost is saved.

Description

technical field [0001] The invention relates to a process for extracting and separating rare earth elements with an acidic organic extractant. Specifically, an acidic organic extractant is mixed with an aqueous solution of an organic acid salt of magnesium and / or calcium and a rare earth solution for pre-extraction, and the rare earth ions are extracted into the organic phase, and after clarification, a loaded organic extractant containing rare earth ions is obtained. The invention relates to the extraction and separation of mixed rare earth feed liquid, and belongs to the field of rare earth solvent extraction and separation. Background technique [0002] At present, the separation and purification of a single rare earth element in industry generally adopts solvent extraction. Phosphoric acid), C272 (two (2,4,4-trimethylpentyl) phosphonic acid) and other extractants extract and separate rare earth elements in hydrochloric acid system ([1] Collected Papers on Rare Earth Che...

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Problems solved by technology

[0009] The above three invention patent applications use alkaline earth metal minerals containing calcium and magnesium, or alkaline earth metal compound powder or slurry containing magnesium and / or calcium, that is, containing magnesium and / or calcium oxides, hydroxides, carbon Salt powder or water slurry is used to pretreat or pre-extract the organic phase. Since alkaline earth metal minerals containing calcium and magnesium and their oxides and hydroxides contain more impurities such as silicon, iron, and aluminum, solid-liquid reaction The speed is slow and incomplete, resulting in three-phase substances in the pretreatment or extraction process, which affects the smooth progress of the extraction process, and impurities such as iron and aluminum are easily extracted into the organic phase, thereby affecting product quality

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