Xiamen Institute of Rare Earth Materials

Yamin Dong

Yanliang Wang

Xiaoqi Sun

Sen Qiu

A method for recovering thorium and rare earth elements from rare earth waste residues includes the steps of (1) mixing rare earth waste residues with an inorganic acid and heating to obtain a stock solution containing thorium and rare earth elements; (2) extracting thorium and rare earth elements from the stock solution with an organic phase containing an extractant; (3) washing the organic phase obtained after extraction in step (2) with a washing solution to move rare earth elements into the aqueous phase and leave thorium in the organic phase; (4) back-extracting the organic phase containing thorium obtained in step (3) with a back-extraction solution to extract move thorium in the organic phase into the aqueous phase. The extractant contains alkyl phosphonic acid monoalkyl ester and dialkylphosphinic acid.

Method for recovering thorium and rare earth elements from rare earth waste residues

An extractant and a method for the extraction and separation of yttrium are disclosed in the invention. Cations of said extractant are selected from the group of quaternary phosphonium or quaternary ammonium, and the anion is sec-octylphenoxy acetate. The extractant has a simple composition, the formulated organic phase has stable properties and can be recycling used without significantly decreased concentration. The present invention used a mixed organic phase consisting of an extractant and a diluent to extract a rare earth feed liquid containing yttrium, and then washed and back extracted it with deionized water so that the consumption of acid and alkali in all the processes of extraction, washing and back extraction was avoided. Therefore, the extraction is carried out under a low acidity and a high extraction efficiency was ensured. The organic phase can be recycling used without saponification, so that no ammonia wastewater was produced in the processes.

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Fujian, China

Yamin Dong