Process for extracting and recovering tantalum present in an acid aqueous phase by means of an ionic liquid, and use of such an ionic liquid for extracting the tantalum from an acid aqueous phase

Patent metadata

Field	Value
Publication number	US-2018230572-A1
Application number	US-201615751307-A
Country	US
Kind code	A1
Filing date	Aug 10, 2016
Priority date	Aug 10, 2015
Publication date	Aug 16, 2018
Grant date	—

Abstract

A method for extracting the tantalum from an acid aqueous phase A1 comprising at least one step comprising the bringing of the aqueous phase A1 into contact with a phase A2 not miscible with water, and then the separation of the aqueous phase A1 from the phase A2, the phase A2 consisting of one ionic liquid or a mixture of ionic liquids as an extractant. A method for recovering the tantalum that implements this extraction method and to a use of an ionic liquid or of a mixture of ionic liquids as an extractant, in order to extract the tantalum from such an aqueous phase A1.

First claim

What is claimed is:

1 . Method for extracting the tantalum from an acid aqueous phase A1 comprising at least one step comprising the bringing of the aqueous phase A1 into contact with a phase A2 that is not miscible with water, and then the separation of the aqueous phase A1 from the phase A2, characterised in that the phase A2 consists of one ionic liquid or a mixture of ionic liquids as an extractant.

2 . Extraction method according to claim 1 , wherein the phase A2 consists of one ionic liquid.

3 . Extraction method according to claim 1 , wherein the ionic liquid or the ionic liquids comprise an organic cation and an anion, said organic cation comprises a nitrogen group chosen from the group consisting of a quaternary ammonium, which is cyclical or non-cyclical, a phosphonium, a piperidinium, a pyridinium, a pyrrolidinium, a piperazinium and an imidazolium.

4 . Extraction method according to claim 3 , wherein the organic cation is chosen from the group consisting of a piperidinium, a pyridinium, a pyrrolidinium, a piperazinium and an imidazolium.

5 . Extraction method according to claim 4 , wherein the organic cation is chosen from the group consisting of a dialkylpiperidinium, an alkylpyridinium, an N,N′-dialkylpiperazinium and an N,N′-dialkylimidazolium.

6 . Extraction method according to claim 3 , wherein the organic cation further comprises at least one functional group chosen from a ketone, an alcohol, a phosphonate and a phosphine oxide.

7 . Extraction method according to claim 6 , wherein the functional group is a phosphonate.

8 . Extraction method according to claim 3 , wherein the anion is chosen from bis-(trifluoromethanesulfonyl)imide, hexafluorophosphate and bis-(fluorosulfonyl)imide and is advantageously bis-(trifluoromethanesulfonyl)imide.

9 . Extraction method according to claim 8 , wherein the ionic liquid is chosen from:
N-ethyl-N-(4-methyl-2-oxopentyl)-piperidinium bis-(trifluoromethanesulfonyl)imide, N-methyl-N-(4-methyl-2-oxopentyl)imidazolium bis-(trifluoromethanesulfonyl)imide, N-(4-methyl-2-oxopentyl)pyridinium bis-(trifluoromethanesulfonyl)imide, (4-(dibutoxyphosphoryl)-butyl)ethylpiperidinium bis-(trifluoromethanesulfonyl)imide, ethylbutylpiperidinium bis-(trifluoromethanesulfonyl)imide, and methylimidazolium bis-(trifluoromethanesulfonyl)imide.

10 . Extraction method according to claim 1 , carried out at ambient temperature.

11 . Method for recovering the tantalum present in an acid aqueous phase A1, characterised in that it comprises:
(a) the extraction of the tantalum from the aqueous phase A1 by an extraction method according to claim 1 ; and (b) the stripping of said tantalum present in the phase A2 as obtained after step (a), or (b′) the electrodeposition of said tantalum present in the phase A2 as obtained after step (a).

12 . Recovery method according to claim 11 , wherein the step (b) of stripping comprises the bringing of this phase A2 into contact with an aqueous phase A3 having a pH that is less than or equal to 7, and then the separation of the phase A2 from the aqueous phase A3.

13 . Recovery method according to claim 11 , wherein the step (b′) of electrodeposition involves applying a difference in potential between a cathode and a reference electrode, in the presence of a working electrode, all of these electrodes being placed in this phase A2, between −0.8 V and −2.4 V.

14 . Extraction method according to claim 1 , wherein the aqueous phase A1 is an acid digestion solution of a concentrate of a natural or urban ore comprising said tantalum.

15 . Extraction method according to claim 14 , wherein the aqueous phase A1 comprises at least one inorganic acid chosen from the group consisting of hydrofluoric acid, sulphuric acid, nitric acid, phosphoric acid and hydrochloric acid.

16 . Extraction method according to claim 15 , wherein the aqueous phase A1 has a total molar concentration of inorganic acid(s) of at least 0.1 mol/L, advantageously from 1 mol/L to 14 mol/L and, preferably, from 3 mol/L to 9 mol/L.

17 . Use of one ionic liquid or of a mixture of ionic liquids as an extractant, in order to extract the tantalum from an acid aqueous phase A1, said ionic liquid(s) comprising an organic cation and an anion, said organic cation comprising a nitrogen group chosen from the group consisting of a piperidinium, a pyridinium, a pyrrolidinium, a piperazinium and an imidazolium.

18 . Use according to claim 17 , wherein the organic cation is chosen from the group consisting of a dialkylpiperidinium, an alkylpyridinium, an N,N′-dialkylpiperazinium and an N,N′-dialkylimidazolium.

19 . Use according to claim 17 , wherein the organic cation further comprises at least one functional group chosen from a ketone, an alcohol, a phosphonate and a phosphine oxide.

20 . Use according to claim 17 , wherein the anion is bis-(trifluoromethanesulfonyl)imide.

21 . Use according to claim 17 , wherein the extraction is carried out via the technique of liquid-liquid extraction.

22 . Recovery method according to claim 11 , wherein the aqueous phase A1 is an acid digestion solution of a concentrate of a natural or urban ore comprising said tantalum.

23 . Recovery method according to claim 22 , wherein the aqueous phase A1 comprises at least one inorganic acid chosen from the group consisting of hydrofluoric acid, sulphuric acid, nitric acid, phosphoric acid and hydrochloric acid.

24 . Recovery method according to claim 23 , wherein the aqueous phase A1 has a total molar concentration of inorganic acid(s) of at least 0.1 mol/L, advantageously from 1 mol/L to 14 mol/L and, preferably, from 3 mol/L to 9 mol/L.

Assignees

• Centre Nat Rech Scient
• Univ Montpellier
• Univ De Chambery
• Enscm
• TND

Inventors

• Turgis Raphael
• Arrachart Guilhem
• Pellet-Rostaing Stéphane
• Draye Micheline
• Legeai Sophie
• Virieux David
• Thomas Christian

Classifications

• C22B34/24 Primary

  Obtaining niobium or tantalum · CPC title

• C22B3/0005

  Chemistry & Metallurgy · mapped topic

• C25C1/06

  or iron group metals, refractory metals or manganese · CPC title

• C22B3/42

  by ion-exchange extraction · CPC title

• C01G35/003

  Preparation involving a liquid-liquid extraction, an adsorption or an ion-exchange · CPC title