Cobalt is essential for producing lithium-ion batteries and is extensively used in electric vehicles, computers, and smartphones. As demand for electric vehicles rises, global cobalt demand is projected to quadruple.
Beyond batteries, cobalt is crucial for producing specialized blue pigments, medical devices, and various alloys, underscoring its importance across multiple sectors; however, cobalt extraction presents serious environmental and human rights issues, therefore, recycling and reusing this metal is receiving more attention.
Recycling valuable metals from used lithium-ion batteries
US patent US10741890B2 describes a method and apparatus for recycling lithium-ion batteries to recover valuable metals such as cobalt (Co), nickel (Ni), manganese (Mn), and lithium (Li) from used battery cathodes.
The process includes physical separation, acid leaching, pH adjustment, precipitation, and sintering to process valuable recovered metals into active materials for new batteries. This method addresses the challenges of traditional high-temperature recycling processes by achieving high recovery rates through chemical leaching and co-precipitation and producing high-quality recycled materials that promote environmental sustainability and resource conservation. In summary, the key recycling steps encompass physical separation, acid leaching, pH adjustment, precipitation, sintering, and treatment of ferric phosphate (FePO₄) and graphite.
US patent US11769916B2 from Worcester Polytechnic Institute (WPI) outlines a method for recycling lithium-ion batteries by dissolving cathode materials from discarded batteries to extract elements like cobalt, nickel, aluminum, and manganese. These elements are then used to manufacture active cathode materials for new batteries, eliminating the need for high temperatures or complex separation processes.
This approach allows recycled active materials to be reused in the production of new lithium-ion batteries, thereby reducing waste and the need for new raw material extraction. This process is capable of handling various lithium-ion battery chemicals, making it suitable for a broad range of battery recycling applications.
Electrochemical dissolution for recovering precious metals from ruthenium-cobalt (RuCo) alloys
Taiwanese patent TWI404830B involves an electrochemical dissolution method for ruthenium-cobalt (RuCo) alloys. This method utilizes an electrolyte containing sulfuric acid and various solutes or salts to effectively recover precious metals from RuCo alloys through electrochemical dissolution. The patented method allows for the direct electrochemical dissolution of large materials without the need for pre-treatment, thereby streamlining the process and reducing costs.
With optimized concentrations of sulfuric acid and salts, the method maintains high dissolution efficiency. It applies to diverse compositions of RuCo alloys and can also include other precious metals such as platinum, rhodium, palladium, iridium, osmium, titanium, and chromium, enhancing the ability to recover different alloys. The optimized conditions ensure high dissolution efficiency while maintaining safety and cost-effectiveness in the recovery process.
Applications of cobalt in integrated circuits
US patent US11894437B2 uses ruthenium as a liner and cobalt as a filler material to create a metal coating in integrated circuits (IC). The patent aims to form source-drain conductive structures by sequentially depositing ruthenium and cobalt metals, followed by reflow and planarization processes.
This technique results in reduced resistance and enhanced integration characteristics, wherein the source-drain structure consists of a cobalt core surrounded by a ruthenium liner. This hybrid structure, known as a mixed conductive structure, combines two different metals to optimize performance.
The mixed conductive structure delivers enhanced electrical performance and is compatible with existing CMOS processes while reducing overall resistance. The cobalt core primarily provides a low-resistance electrical signal pathway.
Applications of cobalt in anode materials for secondary batteries
Taiwanese patent TWI736105B introduces a new material for anode applications in secondary batteries, comprising composite metal oxides and oxide mixtures with four or more elements. This innovation aims to enhance battery capacity and stability.
The materials include cobalt-copper-tin oxides, such as Co₅Cu₁Sn₃MOₓ₁ and Co₂Cu₁Sn₁MOₓ₂. The preparation methods for these composite oxides include hydrothermal synthesis, co-precipitation, sol-gel processes, and solid-state reactions. The choice of method depends on the desired crystal structure and stoichiometry, optimizing lithium ion mobility and structural stability during battery cycles.
Prioritizing cobalt recycling
Recycling and reusing cobalt are essential for protecting the environment, managing resources, and providing economic benefits.
1. Resource conservation: cobalt is a limited natural resource. Recycling and reuse can reduce the need for new cobalt mining, conserving valuable resources
2. Reducing environmental impact: the extraction and refining of cobalt can have significant environmental consequences. Recycling and reuse can help mitigate these impacts.
3. Economic benefits: cobalt recycling and reuse can provide economic advantages. For instance, Apple aims to use 100% recycled cobalt in its batteries by 2025. Additionally, by 2030, the global market for recycled and reused batteries is expected to reach US$40.6 billion.
4. Reducing energy consumption and carbon emissions: the refining process for cobalt requires significant energy and generates carbon dioxide. Recycling and reuse can help lower energy consumption and reduce carbon emissions.
Risks associated with cobalt export
Cobalt is indeed a critical mineral with crucial applications across various fields. For example, its importance in manufacturing electric vehicle batteries is comparable to that of crude oil in the automotive industry.
However, according to a report by the Organisation for Economic Co-operation and Development (OECD), critical raw materials like lithium and cobalt are increasingly subject to export restrictions.
These critical materials are concentrated in a few countries, affecting supply and prices. With the intensifying geopolitical risks between China and the US, export controls are often used as a tool to navigate the complex bilateral relationship. Such restrictions could severely hinder global progress toward green economies, and cobalt's export carries certain risks.
This article explores cobalt recycling processes and their applications in integrated circuits and secondary batteries, offering insights for industries in Taiwan. (The views and opinions expressed in this article are solely those of the author and do not necessarily reflect the position of their affiliated organization.)
