Method of separating and recovering cobalt salt and nickel salt

Patent metadata

Field	Value
Publication number	US-12403427-B2
Application number	US-202117928262-A
Country	US
Kind code	B2
Filing date	May 28, 2021
Priority date	May 29, 2020
Publication date	Sep 2, 2025
Grant date	Sep 2, 2025

Abstract

A method of separating and recovering a cobalt salt and a nickel salt includes a separation step of separating, by using a nanofiltration membrane, a cobalt salt and a nickel salt from a rare metal-containing aqueous solution containing at least both the cobalt salt and the nickel salt as rare metals, in which the nanofiltration membrane has a glucose permeability of 3 times or more a sucrose permeability, the sucrose permeability of 10% or less, and an isopropyl alcohol permeability of 50% or more when a 1,000 mg/L glucose aqueous solution, a 1,000 mg/L sucrose aqueous solution, and a 1,000 mg/L isopropyl alcohol aqueous solution, each having a pH of 6.5 and a temperature of 25° C., individually permeate through the nanofiltration membrane at an operating pressure of 0.5 MPa.

First claim

The invention claimed is:

1. A method of separating and recovering a cobalt salt and a nickel salt, the method comprising a separation step of separating, by using a nanofiltration membrane, a cobalt salt and a nickel salt from a rare metal-containing aqueous solution containing at least both the cobalt salt and the nickel salt as rare metals,
wherein the nanofiltration membrane has a glucose permeability of 3 times or more a sucrose permeability, the sucrose permeability of 10% or less, and an isopropyl alcohol permeability of 50% or more when a 1,000 mg/L glucose aqueous solution, a 1,000 mg/L sucrose aqueous solution, and a 1,000 mg/L isopropyl alcohol aqueous solution, each having a pH of 6.5 and a temperature of 25° C., individually permeate through the nanofiltration membrane at an operating pressure of 0.5 MPa.

2. The method according to claim 1 , wherein the nanofiltration membrane comprises a base material, a support membrane on the base material, and a separation function layer on the support membrane, and
the separation function layer comprises a polyamide having a structure derived from a polyfunctional aliphatic amine and a structure derived from a polyfunctional acid halide.

3. The method according to claim 2 , wherein the polyfunctional aliphatic amine is a compound represented by formula (1),

provided that R 1 and R 2 each independently represent an alkyl group having 1 to 6 carbon atoms, a phenyl group, a benzyl group, COOR 5 , CONHR 5 , CON(R 5 ) 2 , or OR 5 , and R 5 represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a phenyl group, or a benzyl group; and R 3 and R 4 each independently represent hydrogen, an alkyl group having 1 to 6 carbon atoms, a phenyl group, a benzyl group, COOR 6 , CONHR 6 , CON(R 6 ) 2 , or OR 6 , and R 6 represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a phenyl group, or a benzyl group.

4. The method according to claim 2 , wherein the polyamide is a crosslinked aromatic polyamide having a structure represented by formula (2),

provided that R 1 and R 2 each independently represent an alkyl group having 1 to 6 carbon atoms, a phenyl group, a benzyl group, COOR 5 , CONHR 5 , CON(R 5 ) 2 , or OR 5 , and R 5 represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a phenyl group, or a benzyl group; R 3 and R 4 each independently represent hydrogen, an alkyl group having 1 to 6 carbon atoms, a phenyl group, a benzyl group, COOR 6 , CONHR 6 , CON(R 6 ) 2 , or OR 6 , and R 6 represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a phenyl group, or a benzyl group; R 7 is an aliphatic chain or an aliphatic ring comprising only a carbon atom and a hydrogen atom as a constituent element; and Ar 8 is an aromatic ring having 6 to 14 carbon atoms which may have a substituent.

5. The method according to claim 1 , further comprising a complex forming step of adding a complex forming agent to the rare metal-containing aqueous solution before the separation step,
wherein the complex forming agent has a solubility in water of 100 mg/L or more.

6. The method according to claim 5 , wherein the complex forming step comprises a step of adjusting a pH of the rare metal-containing aqueous solution to 1 or more and 9 or less.

7. The method according to claim 5 , wherein the complex forming step comprises a step of adding an amine-based ligand as the complex forming agent.

8. The method according to claim 1 , further comprising, before the separation step, an acid treatment step of bringing a material containing at least both cobalt and nickel as rare metals into contact with an acid aqueous solution to obtain the rare metal-containing aqueous solution.

9. The method according to claim 8 , further comprising a mixing step of mixing a permeated water generated in a concentration step with the rare metal-containing aqueous solution obtained in the acid treatment step,
wherein, in the separation step, the permeated water and a concentrated water are obtained from a mixed water obtained in the mixing step.

10. The method according to claim 1 , wherein the separation step comprises at least a first separation step and a 2a-th separation step which use the nanofiltration membrane, and
a permeated water obtained in the first separation step is treated in the 2a-th separation step.

11. The method according to claim 10 , wherein the permeated water obtained in the first separation step is diluted to be treated in the 2a-th separation step.

12. The method according to claim 1 , wherein the separation step comprises at least a first separation step and a 2b-th separation step which use the nanofiltration membrane, and
a non-permeated water obtained in the first separation step is treated in the 2b-th separation step.

13. The method according to claim 12 , wherein the non-permeated water obtained in the first separation step is diluted to be treated in the 2b-th separation step.

14. The method according to claim 1 , further comprising, before the separation step, a pre-separation step of separating an alkali metal salt and a polyvalent rare metal salt by using the nanofiltration membrane, to obtain a permeated water in which an alkali metal ion concentration (mg/L) is 100 times or more a polyvalent rare metal ion concentration (mg/L).

15. The method according to claim 1 , further comprising a concentration step of concentrating an aqueous solution obtained in the separation step with a reverse osmosis membrane.

Assignees

• Toray Industries

Inventors

• Yoshizaki Tomoya
• Soya Takanori
• Koiwa Masakazu
• Hanada Shigehisa

Classifications

• B01D69/10

  Supported membranes; Membrane supports · CPC title

• B01D69/12

  Composite membranes; Ultra-thin membranes · CPC title

• C22B23/0453

  Treatment or purification of solutions, e.g. obtained by leaching (C22B23/0407 takes precedence) · CPC title

• C22B23/0407

  Leaching processes · CPC title

• C22B3/22

  by physical processes, e.g. by filtration, by magnetic means {, or by thermal decomposition} (treatment or purification of solutions by liquid-liquid extraction C22B3/26) · CPC title