Method and apparatus for extracting lithium from solution using bipolar electrodes

Patent metadata

Field	Value
Publication number	US-2023212769-A1
Application number	US-202218086697-A
Country	US
Kind code	A1
Filing date	Dec 22, 2022
Priority date	Jan 4, 2022
Publication date	Jul 6, 2023
Grant date	—

Abstract

An electrochemical method and an apparatus for extracting lithium from a solution using bipolar electrodes are provided. The apparatus adopts electrodes respectively coated with a lithium-rich electroactive material and a lithium-deficient electroactive material as end plates, which are separated by a plurality of bipolar electrodes coated with a lithium-rich electroactive material and a lithium-deficient electroactive material respectively on two sides, where the side of the bipolar electrode facing the end plate of the lithium-rich electroactive material is coated with the lithium-deficient electroactive material, and the side of the bipolar electrode facing the end plate of the lithium-deficient electroactive material is coated with the lithium-rich electroactive material. The apparatus adopts a conventional voltage, requires a small total current and a simple power supply, greatly reduced the amount of busbar required, allows for easy process control, and is suitable for industrial production.

First claim

What is claimed is:

1 . An apparatus for extracting lithium from a solution using bipolar electrodes, comprising a cell body, end electrodes, at least one conductive separator, and anion membranes, wherein a number of the anion membranes is greater than a number of the at least one conductive separator;
wherein the end electrodes comprise a first end electrode and a second end electrode respectively disposed at two ends of the cell body, the first end electrode is configured to connect to a first electrode, and the second end electrode is configured to connect to a second electrode; a surface of the first end electrode facing the second end electrode is coated with a lithium-deficient electroactive material, and a surface of the second end electrode facing the first end electrode is coated with a lithium-rich electroactive material; wherein the at least one conductive separator is disposed inside the cell body to physically divide the cell body into two or more independent chambers, and the at least one conductive separator is located between the first end electrode and the second end electrode; a first surface of the at least one conductive separator facing the first end electrode is coated with the lithium-rich electroactive material, and a second surface of the at least one conductive separator facing the second end electrode is coated with the lithium-deficient electroactive material; and wherein one of the anion membranes is disposed in each of the independent chambers to divide the each of the independent chambers into two working areas, one of the two working areas is on a lithium-deficient electroactive material side and is used for introducing a lithium-containing raw material solution and is called a first working area, and the other of the two working areas is on a lithium-rich electroactive material side and is used for introducing a supporting electrolyte solution and is called a second working area.

2 . The apparatus for extracting the lithium from the solution using the bipolar electrodes according to claim 1 , wherein the first end electrode, the second end electrode, the at least one conductive separator, and the anion membranes are disposed in parallel with each other, and a plurality of the at least one conductive separator is spaced apart from each other by a same distance.

3 . The apparatus for extracting the lithium from the solution using the bipolar electrodes according to claim 1 , wherein at least one engagement groove for mounting the at least one conductive separator is provided in the cell body.

4 . The apparatus for extracting the lithium from the solution using the bipolar electrodes according to claim 1 , wherein the lithium-rich electroactive material is at least one of LiFePO 4 , LiMn 2 O 4 , LiMeO 2 , and doped derivatives of the LiFePO 4 , the LiMn 2 O 4 , and the LiMeO 2 , wherein Me is one or more of Ni, Co, or Mn; and the lithium-deficient electroactive material is prepared by oxidizing the lithium-rich electroactive material to remove a part or all of the lithium.

5 . The apparatus for extracting the lithium from the solution using the bipolar electrodes according to claim 1 , wherein the at least one conductive separator is a carbon paper; a carbon fiber sintered cloth; a graphite plate; a corrosion-resistant intermetallic compound plate; a ruthenium-coated titanium sheet; a plate of gold, a platinum group metal, and/or an alloy of the gold and the platinum group metal; or a plate of titanium, zirconium, hafnium, tantalum, niobium, and/or an alloy of the titanium, the zirconium, the hafnium, the tantalum, and the niobium.

6 . A method for extracting lithium from a solution using bipolar electrodes, comprising the following steps:
step 1: taking the apparatus for extracting the lithium from the solution using the bipolar electrodes according to claim 1 , introducing the lithium-containing raw material solution into the first working area, and introducing the supporting electrolyte solution into the second working area; step 2: connecting the first end electrode to a negative electrode of a power supply, connecting the second end electrode to the negative electrode of the power supply, turning on the power supply, a current flowing in from the second end electrode and being outputted from the first end electrode, and at the same time, the following changes occur: lithium ions in the lithium-containing raw material solution in the first working area are intercalated in the lithium-deficient electroactive material, and the lithium-deficient electroactive material becomes the lithium-rich electroactive material; and lithium ions are deintercalated from the lithium-rich electroactive material in the second working area and enter the supporting electrolyte solution, and the lithium-rich electroactive material becomes the lithium-deficient electroactive material; step 3: when the lithium-containing raw material solution has changed into a lithium-deficient solution and the supporting electrolyte solution has changed into a lithium-rich solution, disconnecting the power supply, discharging the lithium-deficient solution, and collecting the lithium-rich solution; and step 4: cleaning the cell body, connecting the first end electrode to a positive electrode of the power supply, connecting the second end electrode to the negative electrode of the power supply, and repeating the steps 1-3.

7 . The method for extracting the lithium from the solution using the bipolar electrodes according to claim 6 , wherein the lithium-rich solution from one cycle is used as the supporting electrolyte solution in a next cycle for a lithium extraction to increase a concentration of the lithium in the solution; and the lithium-deficient solution from the one cycle is used as the lithium-containing raw material solution for the lithium extraction in the next cycle to improve a recovery rate of the lithium.

8 . The method for extracting the lithium from the solution using the bipolar electrodes according to claim 6 , wherein the lithium-containing raw material solution for a lithium extraction is at least one of a raw salt lake brine, a brine of any stage obtained by a treatment of an original brine, an old brine, an underground brine, an oil field brine, a lithium-containing solution obtained from an ore decomposition and a secondary resource recovery, or a lithium precipitation mother liquor.

9 . The method for extracting the lithium from the solution using the bipolar electrodes according to claim 6 , wherein a value of a voltage of the power supply is (0.1-1.0)×n V, wherein n is a number of the independent chambers.

10 . The method for extracting the lithium from the solution using the bipolar electrodes according to claim 9 , wherein
when the lithium-rich electroactive material is LiFePO 4 or a derivative of the LiFePO 4 , an external voltage applied is (0.1-0.5)×n V; when the lithium-rich electroactive material is LiMn 2 O 4 or a derivative of the LiMn 2 O 4 , an external voltage applied is (0.3-0.6)×n V; when the lithium-rich electroactive material is LiMeO 2 or a derivative of the LiMeO 2 , an external voltage applied is (0.4-0.8)×n V; when the lithium-rich electroactive material is LiMn 2 O 4 , LiFePO 4 , and a derivative of the LiMn 2 O 4 or the LiFePO 4 , an external voltage applied is (0.3-0.7)×n V; when the lithium-rich electroactive material is LiMn 2 O 4 , LiMeO 2 , and a derivative of the LiMn 2 O 4 or the LiMeO 2 , an external voltage applied is (0.4-0.9)×n V; or when the lithium-rich electroactive material is LiFePO 4 , LiMeO 2 , and a derivative of the LiFePO 4 or LiMeO 2 , an external voltage applied is (0.4-1.0)×n V.

11 . The method for extra

Assignees

• Univ Central South

Inventors

• Zhao Zhongwei
• He Lihua
• Liu Xuheng

Classifications

• C25C7/04

  Diaphragms; Spacing elements · CPC title

• C25C7/02 Primary

  Electrodes (consumable anodes for the refining the metals C25C1/00 - C25C5/00); Connections thereof · CPC title

• C25C1/02 Primary

  of light metals · CPC title

• C25C7/08

  Separating of deposited metals from the cathode · CPC title

• Y02P10/20

  Recycling · CPC title