Molten salt electrorefiner

Patent metadata

Field	Value
Publication number	US-11401617-B2
Application number	US-201816767591-A
Country	US
Kind code	B2
Filing date	Nov 28, 2018
Priority date	Nov 29, 2017
Publication date	Aug 2, 2022
Grant date	Aug 2, 2022

Abstract

The present invention provides a molten-salt electrolytic refining apparatus for refining a raw-material alloy containing indium using a molten-salt electrolytic refining method. The molten-salt electrolytic refining apparatus includes a reaction crucible provided in a reaction container so as to be filled with a molten-salt electrolytic solution, an anode and a cathode immersed in the molten-salt electrolytic solution, an anode crucible in which a liquid raw-material alloy is contained, a cathode crucible in which at least one raw-material metal included in the raw-material alloy is recovered in a liquid phase, and a heater provided so that the temperature of the molten-salt electrolytic solution is adjusted to be equal to or greater than the melting temperature of the raw-material alloy. The present invention also provides a molten-salt electrolytic refining method which includes recovering indium (In) from an indium-tin (In—Sn) alloy using a molten-salt electrolytic solution containing fluoride.

First claim

The invention claimed is:

1. A molten-salt electrolytic refining apparatus comprising:
a reaction container having a hollow portion therein and an upper cover provided at an opened top portion thereof to be sealed;
a reaction crucible provided in the reaction container so as to be filled with a molten-salt electrolytic solution;
an anode and a cathode immersed in the molten-salt electrolytic solution;
an anode crucible in which a raw-material alloy is contained so that a lower end of the anode is immersed in a liquid raw-material alloy to be refined;
a cathode crucible in which a lower end of the cathode is positioned so that at least one raw-material metal included in the raw-material alloy is recovered in a liquid phase through an electrolytic refining process;
a heater provided between the reaction container and the reaction crucible so that a temperature of the molten-salt electrolytic solution is adjusted to be equal to or greater than a melting temperature of the raw-material alloy; and
a holding plate on which the reaction crucible is seated,
wherein an electrolytic refining process is performed when the holding plate is moved upwards so as to bring a molten-salt electrolytic solution into contact with an anode and a cathode, and the electrolytic refining process is stopped when the holding plate is moved downwards so as to enable the molten-salt electrolytic solution to be spaced apart from the anode and the cathode.

2. The molten-salt electrolytic refining apparatus of claim 1 , wherein an electrolytic refining process is performed when an anode and a cathode are moved downwards so as to be brought into contact with a molten-salt electrolytic solution, and the electrolytic refining process is stopped when the anode and the cathode are moved upwards so as to be spaced apart from the molten-salt electrolytic solution.

3. The molten-salt electrolytic refining apparatus of claim 1 , wherein the anode includes a hollow portion therein, and the raw-material metal is continuously supplied in the liquid phase through the hollow portion to the anode crucible.

4. The molten-salt electrolytic refining apparatus of claim 1 , further comprising:
a discharge unit for discharging an unreacted alloy remaining in the anode crucible; and
a recovery unit for recovering the raw-material metal from the cathode crucible.

5. The molten-salt electrolytic refining apparatus of claim 1 , wherein an indium-tin (In—Sn) alloy is charged as the raw-material alloy and indium (In) is recovered as the raw-material metal.

6. A molten-salt electrolytic refining method comprising:
recovering indium (In) from an indium-tin (In—Sn) alloy using a molten-salt electrolytic solution containing a fluoride,
filling a reaction crucible provided in a reaction container with the molten-salt electrolytic solution, immersing an anode and a cathode in the molten-salt electrolytic solution, immersing a lower end of the anode in an anode crucible in which the liquid indium-tin (In—Sn) alloy is contained, and disposing a cathode crucible in which a lower end of the cathode is positioned;
adjusting a temperature of the molten-salt electrolytic solution to be equal to or greater than a melting temperature of the indium-tin (In—Sn) alloy using a heater provided between the reaction container and the reaction crucible;
applying an electric current to the anode and cathode, thus performing an electrolytic refining process; and
recovering the indium (In) from the cathode crucible using the electrolytic refining process,
wherein the reaction crucible is seated on a holding plate,
wherein the electrolytic refining process is performed when the holding plate is moved upwards so as to bring the molten-salt electrolytic solution into contact withe the anode and the cathode, and the electrolytic refining process is stopped when the holding plate is moved downwards so as to enable the molten-salt electrolytic solution to be spaced apart from the anode and the cathode.

7. The molten-salt electrolytic refining method of claim 6 , wherein the fluoride includes lithium fluoride (LiF) and potassium fluoride (KF).

8. The molten-salt electrolytic refining method of claim 6 , wherein the indium-tin (In—Sn) alloy is continuously supplied through a hollow portion in the anode to the anode crucible.

9. The molten-salt electrolytic refining method of claim 6 , wherein the molten-salt electrolytic refining method is continuously performed in such a way that the indium (In) is recovered from the cathode crucible while an unreacted alloy remaining in the anode crucible is discharged.

10. The molten-salt electrolytic refining method of claim 6 , further comprising:
performing a vacuum distillation process on the recovered indium (In).

11. The molten-salt electrolytic refining method of claim 10 , wherein the performing the vacuum distillation process includes:
a first step of removing at least one impurity having a saturation vapor pressure that is relatively higher than a saturation vapor pressure of the indium (In) using a first vacuum distillation process in a predetermined temperature range; and
a second step of volatilizing the indium (In) using a second vacuum distillation process in a temperature range relatively higher than in the first step, thus recovering high-purity indium (In).

Assignees

• Korea Inst Ind Tech

Inventors

• Park Kyoung-Tae
• Kim Taek-Soo
• Choi Sang-Hoon
• Lee Hyun-Gyu
• Sim Jae-Jin
• Lim Jae-Hong

Classifications

• C22B58/00

  Obtaining gallium or indium {(treatment or purification of solutions by liquid-liquid extraction, by ion-exchange or by adsorption C22B3/20)} · CPC title

• C25C3/34

  of metals not provided for in groups C25C3/02 - C25C3/32 · CPC title

• C25C7/00

  Constructional parts, or assemblies thereof, of cells; Servicing or operating of cells (for the production of aluminium C25C3/06 - C25C3/22) · CPC title

• C25C7/08

  Separating of deposited metals from the cathode · CPC title

• C25C7/005 Primary

  of cells for the electrolysis of melts (C25C7/02 - C25C7/06 take precedence) · CPC title