Counter-Current Leaching for Lithium Battery Metal Recovery
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Solution Overview
Problem
Conventional methods for recovering valuable metals like cobalt, nickel, and lithium from lithium secondary battery wastes require excessive amounts of acids and neutralizing agents due to incomplete leaching, leading to increased operational costs and inefficiencies.
Innovation Solution
A two-step counter-current leaching process using a mixture of inorganic acid and hydrogen peroxide minimizes acid usage, followed by purification and solvent extraction with specific agents like D2EHPA, CYANEX 272, and VS-10 to achieve 100% leaching and separation of Co, Ni, Mn, and Li, reducing the need for neutralizing agents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional single-step leaching with highly concentrated acids is used, then leaching rate of metals is improved, but excessive amounts of acids remain in the leaching solution requiring large amounts of expensive neutralizing agents
Solution Approach 1:
The leaching process is divided into two distinct steps: first leaching with inorganic acid to dissolve metals, then a second leaching step with hydrogen peroxide to complete the dissolution. This segmentation allows each step to be optimized independently, achieving complete leaching while controlling acid consumption and enabling easier neutralization.
Solution Approach 2:
The invention changes the chemical parameters by introducing hydrogen peroxide as a secondary leaching agent. This parameter change enables complete oxidation and dissolution of metal compounds without requiring excessive inorganic acid, thereby reducing the amount of neutralizing agent needed in subsequent processing.
2Reliability
If excessive amounts of acids are used in the leaching process, then complete leaching of valuable metals is achieved, but the cost increases due to large amounts of neutralizing agents required
Solution Approach 1:
Hydrogen peroxide serves as an intermediary oxidizing agent that facilitates complete metal dissolution without requiring excessive inorganic acid. It mediates the leaching process by providing the necessary oxidation power while being easier to neutralize and remove from the solution, thus reducing neutralizing agent consumption.
Solution Approach 2:
The invention converts the potentially harmful effect of requiring large amounts of neutralizing agents into a benefit by using hydrogen peroxide, which decomposes into water and oxygen. This transforms a costly waste treatment problem into an environmentally friendly solution where the byproducts are harmless.
3Loss of substance
If conventional leaching methods are used, then metal recovery is achieved, but operational efficiency is reduced due to incomplete leaching requiring additional processing
Solution Approach 1:
The two-step leaching process ensures continuous and complete dissolution of all metal compounds. The first step with inorganic acid followed by the second step with hydrogen peroxide creates a continuous action that achieves complete leaching in a systematic manner, eliminating the need for repeated or extended processing and thereby improving operational efficiency.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method achieves complete recovery of high-purity Co, Ni, Mn, and Li while minimizing acid and neutralizing agent usage, enhancing operational efficiency and reducing costs, and allows for improved filtration properties.
Implementation Method 1
a two-step counter-current leaching using an inorganic acid solution or a mixed solution of an inorganic acid and hydrogen peroxide
Implementation Method 2
liquid-phase leaching a scrap powder containing Co, Ni, Mn, and Li, and purifying and solvent-extracting the resulting leaching solution
Implementation Method 3
purifying and solvent-extracting the resulting leaching solution to recover each of said Co, Ni, Mn, and Li
Data Source
AI summary
Valuable metals such as cobalt, nickel, manganese, and lithium can be economically recovered from various lithium secondary battery-related wastes by the inventive method which comprises liquid-phase leaching a scrap powder containing Co, Ni, Mn, and Li, and purifying and solvent-extracting the resulting leaching solution to recover each of said Co, Ni, Mn, and Li, wherein the liquid-phase leaching is performed by a two-step counter-current leaching using an inorganic acid solution or a mixed solution of an inorganic acid and hydrogen peroxide.