An extraction method for separating and purifying heavy rare earth

Abstract

An extraction method for separating and purifying heavy rare earths, the method uses an organic relative sulfuric acid rare earth solution containing an extractant and a diluent for extraction; the extractant is an ether amide functional ionic liquid. The method adopts water as a back-extraction liquid to back-extract the rare earth elements extracted into the n-heptane to obtain a rare-earth-containing back-extraction liquid to realize the extraction and separation of the rare earth elements. In the present invention, because the ether oxygen bond in the ether amide functional ionic liquid structure improves its solubility in diluents and its affinity to rare earth ions, its separation ability between rare earth elements has been significantly improved, especially In the extraction process, the heavy rare earth elements are preferentially extracted, and there is no need for iron and aluminum pretreatment, and in the subsequent stripping process, the heavy rare earth stripping can usually be achieved with only water, reducing the consumption of acid and alkali. The present invention has good interface phenomenon in the extraction process, and the extraction and separation effect can be achieved without saponification of the extraction agent and without addition of a salting-out agent.

Description

technical field [0001] The invention relates to an extraction method for separating and purifying heavy rare earths, belonging to the technical field of rare earth extraction. Background technique [0002] Rare earths have excellent optical, electrical and magnetic properties, and are widely used in the fields of national defense and military industry and high-tech new materials, and have the reputation of "industrial vitamins". Among them, the distribution of medium and heavy rare earths (samarium to lutetium and yttrium) in southern ion-adsorption rare earth mines is as high as 30% to 80%. Close, the product has high added value, and its irreplaceable important application in the fields of high-tech and national defense and military industry really restricts the development of related foreign fields, and it is a strategic resource with absolute competitive advantages. [0003] At present, the separation of single rare earth mainly adopts the extraction and separation meth...

AI Technical Summary

Problems solved by technology

However, the separation of heavy rare earths in the P507 extraction system still has the problems of high acidity in stripping, incomplete stripping, and large acid-base consumption, which affects the separation and high purification of heavy rare earths.

In addition, with the gradual improvement of national environmental protection requirements, the existing P507 extraction system has increasingly prominent problems such as large acid-base consumption and ammonia nitrogen pollution. From the perspective of source prevention, the development of new extraction agents with low acid-base consumption and high selectivity and The extraction system is crucial to the development of a new process for the efficient and clean separation of rare earths

[0004] In recent years, functional ionic liquids have been widely concerned in the field of rare earth separation as a research hotspot in green chemistry. The prior art discloses a variety of methods for separating rare earths with functional ionic liquids as extraction agents. Publication No. CN101723975 discloses "A A kind of preparation method of quaternary ammonium bifunctional ionic liquid "This method adopts the neutralization reaction between quaternary ammonium base and organic phosphine (carboxylic) acid extractant to eliminate hydrogen ions on the extractant, and realizes non-saponification extraction. The prepared acid-base coupling type bifunctional ionic liquid extractant (code-named ABC-BIL) can effectively avoid the pollution caused by the saponification wastewater produced by the application of the phosphine (carboxylic) acid extractant; the publication number CN102618736 discloses a " "Extraction and Separation Method of Rare Earth Elements", using the above-mentioned ionic liquid to extract and separate rare earth elements; however, the functional ionic liquid generally used in the prior art has relatively weak ability to extract and separate trivalent rare earth elements in a sulfuric acid medium , especially for iron, aluminum, zinc and other divalent metals, the removal rate is low, making it difficult to obtain high-purity heavy rare earth products

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