KR-20260065251-A - Lithium Carbonate Precipitation System based on Chemical-free pH Adjustment Using Electrodialysis Systems

KR20260065251AKR 20260065251 AKR20260065251 AKR 20260065251AKR-20260065251-A

Abstract

The present invention provides an electrodialysis system for lithium carbonate precipitation, comprising: a first electrode configured to become a negative electrode when voltage is applied; a second electrode configured to become a positive electrode when voltage is applied; a redox solution storage unit configured to provide a redox reaction material to the first electrode and the second electrode; and a passage connected to the redox solution storage unit configured to allow the redox reaction material to circulate, wherein a bipolar membrane, an anion exchange membrane, and a cation exchange membrane are spaced apart and disposed between the first electrode and the second electrode.

Inventors

윤홍식
전성범
민태진
임성일

Assignees

한국기계연구원

Dates

Publication Date: 20260508
Application Date: 20241101

Claims (13)

As an electrodialysis system for lithium carbonate precipitation, A first electrode configured to become a negative electrode when voltage is applied; A second electrode configured to become a positive electrode when voltage is applied; A redox solution storage unit configured to provide a redox reaction material to the first electrode and the second electrode; and It includes a passage connected to the above redox solution storage unit and configured to allow the redox reaction material to circulate, A bipolar membrane, an anion exchange membrane, and a cation exchange membrane are spaced apart and disposed between the first electrode and the second electrode. Electrodialysis system.
In paragraph 1, The anion exchange membrane is located between the bipolar membrane and the second electrode, and the cation exchange membrane is located between the bipolar membrane and the anion exchange membrane. Electrodialysis system.
In paragraph 1, A method further comprising an input solution storage tank configured to supply a solution containing water or lithium ions between the above-mentioned bipolar membrane and the above-mentioned cation exchange membrane. Electrodialysis system.
In paragraph 3, The above-mentioned input solution storage tank is configured to receive a purified solution from between the cation exchange membrane and the anion exchange membrane, Electrodialysis system.
In paragraph 1, The above redox reaction material is Characterized by being, Electrodialysis system.
In paragraph 1, Characterized that the first electrode and the second electrode are carbon electrodes made of fiber material. Electrodialysis system.
In paragraph 1, It further includes a voltage application unit configured to apply voltage to the first electrode and the second electrode, and The above voltage application unit is configured to apply a voltage of 0V or higher and 1.23V or lower, Electrodialysis system.
In paragraph 1, The above bipolar membrane is composed of a combination of a cation exchange membrane and an anion exchange membrane, and The cation exchange membrane coupled to the above bipolar membrane is directed toward the first electrode, The anion exchange membrane coupled to the above-mentioned bipolar membrane is characterized by being positioned to face the second electrode. Electrodialysis system.
As a lithium carbonate precipitation system, A reaction solution storage unit configured to store a reaction solution containing lithium ions and to allow a lithium carbonate precipitation reaction to occur; A carbon dioxide supply unit configured to supply carbon dioxide to the above reaction solution; A microbubble generating unit configured to generate microbubbles in the above reaction solution; and A system comprising an electrodialysis system according to any one of paragraphs 1 through 8, Lithium carbonate precipitation system.
In Paragraph 9, The above reaction solution storage unit is configured to supply a reaction solution between the cation exchange membrane and the anion exchange membrane of the electrodialysis system. Lithium carbonate precipitation system.
In Paragraph 9, The above electrodialysis system is configured to supply a reaction solution from between the bipolar membrane and the cation exchange membrane to a microbubble generating unit. Lithium carbonate precipitation system.
In Paragraph 9, The above reaction solution storage unit is configured to supply a reaction solution between the bipolar membrane and the cation exchange membrane of the electrodialysis system. Lithium carbonate precipitation system.
In Paragraph 11, Characterized by the pH of the above reaction solution being 9.4 or higher and 14 or lower, Lithium carbonate precipitation system.

Description

Lithium Carbonate Precipitation System based on Chemical-free pH Adjustment Using Electrodialysis Systems The present invention relates to a drug-free pH-controlled lithium carbonate precipitation system using an electrodialysis system, and more specifically, to a system capable of concentrating lithium and controlling pH without the use of drugs using a bipolar membrane electrodialysis system and a redox couple channel (RC). The use of lithium in battery technology began after the first lithium-ion battery (LiB) was commercialized in 1991, and since then, LiBs have become an essential component of portable electronic devices. Additionally, LiBs are growing rapidly across various industries, from power tools to electric vehicles (EVs), and thanks to this rapid development, global lithium production tripled from 2010 to 2020. Lithium is commercially traded in the form of compounds such as lithium carbonate ( Li₂CO₃ ) or lithium hydroxide, with lithium carbonate accounting for the majority (about 60%). As the demand for LiBs increases , the trading volume of lithium carbonate is expected to reach approximately 2 million tons by 2030. Lithium carbonate is produced by separating it from lithium ore or lithium brine lakes, and recently, a method of recovering it from spent batteries through the precipitation of lithium carbonate has been gaining attention. In the lithium carbonate precipitation reaction, sodium carbonate has primarily been used as the main raw material for carbonates. However, the use of sodium carbonate has limitations in that sodium salts become impurities. An alternative method to sodium carbonate is to use carbon dioxide ( CO₂ ) as the raw material for carbonates. This method is superior to the method using sodium carbonate as the raw material for carbonates in terms of purity and recovery rate, and is an eco-friendly technology that can contribute to CO₂ reduction. However, lithium carbonate precipitation technology using carbon dioxide has a problem in that recovery efficiency tends to decrease as the lithium ion concentration in the solution decreases and the pH drops as lithium carbonate precipitation proceeds. To solve this problem, the pH must be maintained at a certain range of 9.4 or higher, which necessitates the addition of chemicals such as sodium hydroxide or calcium hydroxide; however, this results in a decrease in the purity of lithium carbonate due to impurities. Therefore, a technology capable of controlling pH without adding chemicals is required. A brief description of each drawing is provided to help to better understand the drawings cited in this specification. FIG. 1 is a diagram showing a lithium carbonate precipitation system using an electrodialysis system according to one embodiment of the present invention. FIG. 2 is a diagram showing a lithium carbonate precipitation system using an electrodialysis system according to one embodiment of the present invention. FIG. 3 is a diagram showing an electrodialysis system for lithium carbonate precipitation according to one embodiment of the present invention. Figure 4 is a graph showing the change over time in pH and lithium ion concentration (mM) of a reaction solution according to the operation of an electrodialysis system for lithium carbonate precipitation according to one embodiment of the present invention. The technology disclosed in this specification is subject to various modifications and may have various embodiments. Specific embodiments are illustrated in the drawings and described in detail in the detailed description. However, this is not intended to limit the technology disclosed in this specification to specific embodiments, and it should be understood that the technology disclosed in this specification includes all modifications, equivalents, and substitutions that fall within the spirit and scope of the technology disclosed in this specification. In describing the technology disclosed in this specification, if it is determined that a detailed description of related prior art could unnecessarily obscure the essence of the technology disclosed in this specification, such detailed description is omitted. Additionally, numbers used in the description of this specification (e.g., 1st, 2nd, etc.) are merely identification symbols to distinguish one component from another. In addition, when a component is described in this specification as being "connected" or "connected" to another component, it should be understood that the component may be directly connected to or directly connected to the other component, but unless otherwise specifically stated, it may also be connected or connected through another component in between. In addition, components expressed as '~part' in this specification may consist of two or more components combined into a single component, or a single component may be divided into two or more components according to more detailed functions. Furthermore, each component described below may addi