Use of synergistic mixture of extractants for extracting rare earth elements from an aqueous medium comprising phosphoric acid

Patent metadata

Field	Value
Publication number	US-2022010409-A1
Application number	US-201917279411-A
Country	US
Kind code	A1
Filing date	Sep 24, 2019
Priority date	Sep 26, 2018
Publication date	Jan 13, 2022
Grant date	—

Abstract

The use of a synergistic mixture of extractants for extracting at least one rare earth element from an aqueous medium comprising phosphoric acid. The mixture comprises: —a first extractant of formula (I):

wherein R 1 and R 2 , which are identical or different, represent a linear or branched, saturated or unsaturated hydrocarbon group, comprising from 6 to 12 carbon atoms, or a phenyl group optionally substituted by a linear or branched, saturated or unsaturated hydrocarbon group, comprising from 1 to 10 carbon atoms; and —a second extractant of formula (II):

in which R 3 represents a linear or branched alkyl group, comprising from 6 to 12 carbon atoms.
Use of the synergistic mixture in the treatment of phosphate minerals with a view to recovering the rare earth elements contained in the minerals.

First claim

What is claimed is:

1 . A method for extracting at least one rare earth from an aqueous medium comprising phosphoric acid, said method comprising contacting the aqueous medium with a mixture of extractants comprising:
a first extractant of formula (I):

wherein R 1 and R 2 , the same or different, represent a saturated or unsaturated, linear or branched hydrocarbon group, comprising from 6 to 12 carbon atoms, or a phenyl group, optionally substituted by a saturated or unsaturated, linear or branched hydrocarbon group, comprising from 1 to 10 carbon atoms; and
a second extractant or formula (II):

wherein R 3 represents a linear or branched alkyl group, comprising from 6 to 12 carbon atoms; and then separating the aqueous medium from the mixture of extractants.

2 . The method of claim 1 , wherein R 1 and R 2 represent a linear or branched alkyl group, comprising from 6 to 12 carbon atoms, or a phenyl group substituted by a linear or branched alkyl group comprising from 1 to 10 carbon atoms.

3 . The method of claim 2 , wherein R 1 and R 2 represent a linear or branched alkyl group comprising from 8 to 10 carbon atoms, or a phenyl group substituted by a linear or branched alkyl group, comprising from 6 to 10 carbon atoms.

4 . The method of claim 1 , wherein R 1 and R 2 are identical to each other.

5 . The method of claim 1 , wherein the first extractant is di(2-ethylhexyl)phosphoric acid.

6 . The method of claim 1 , wherein R 3 represents a linear or branched alkyl group comprising from 8 to 10 carbon atoms.

7 . The method of claim 6 , wherein the second extractant is N,N,N′,N′-tetraoctyl-diglycolamide.

8 . The method of claim 1 , wherein the mixture of extractants comprises di(2-ethylhexyl)phosphoric acid and N,N,N′,N′-tetraoctyl-diglycol amide.

9 . The method of claim 1 , wherein the mixture of extractants is used in solution in an organic diluent.

10 . The method of claim 1 , wherein contacting the aqueous medium with the mixture of extractants comprises contacting the aqueous medium with an organic solution that is not miscible with water, comprising the mixture of extractants in an organic diluent, and separating the aqueous medium from the mixture of extractants comprises separating the aqueous medium from the organic solution, whereby an organic solution comprising at least the rare earth is obtained.

11 . The method of claim 10 , wherein the organic solution comprises from 0.2 mol/L to 2 mol/L of the first extractant and from 0.05 mol/L to 2 mol/L of the second extractant.

12 . The method of claim 10 , further comprising contacting the organic solution comprising at least the rare earth with an acid or basic aqueous solution, and then separating the organic solution from the aqueous solution, whereby an aqueous solution comprising at least the rare earth is obtained.

13 . The method of claim 1 , wherein the aqueous medium comprises from 0.5 mol/L to 10 mol/L of phosphoric acid.

14 . The method of claim 1 , wherein the aqueous medium is an aqueous solution of phosphoric acid resulting from the lixiviation of a phosphate ore by sulfuric acid.

15 . The method of claim 1 , wherein the rare earth is yttrium, lanthanum, neodymium, dysprosium, or ytterbium.

Assignees

• Commissariat Energie Atomique
• Ocp S A

Inventors

• Andreiadis Eugen
• Duchesne Marie-Thérèse
• Ouaattou Abla
• Mazouz Hamid
• Dhiba Driss

Classifications

• Y02P10/20

  Recycling · CPC title

• C22B3/402

  of acyclic or carbocyclic compounds of different types · CPC title

• C22B3/302

  Ethers or epoxides · CPC title

• C22B59/00 Primary

  Obtaining rare earth metals · CPC title

• C22B3/409

  at least one compound being an organo-metallic compound · CPC title