Lithium-Ion Battery Metal Extraction With Selective Impurity Removal
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Solution Overview
Problem
Existing hydrometallurgical processes for recovering metals from lithium-ion battery black mass are prone to carrying impurities along with the metals of interest, necessitating additional purification steps, particularly due to the unpredictable behavior of hydrogen peroxide as a reducing agent.
Innovation Solution
A process involving acid leaching with sodium thiosulfate as a reducing agent, followed by pH adjustment to form aluminum precipitates, and subsequent use of oxidizing agents to remove iron and manganese, minimizes impurity co-extraction, resulting in a Li/Co-rich solution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hydrogen peroxide is used as a reducing agent in acid leaching, then cobalt is reduced to a more soluble form, but impurities such as copper and phosphorus are carried along with the metals of interest
Solution Approach 1:
The patent changes the chemical parameter by substituting hydrogen peroxide with sodium thiosulfate as the reducing agent. This parameter change fundamentally alters the leaching chemistry to prevent impurity dissolution while maintaining effective cobalt reduction, thereby resolving the contradiction between metal recovery efficiency and impurity co-extraction
Solution Approach 2:
The patent converts the harmful effect of unpredictable reducing agent behavior into a benefit by selecting sodium thiosulfate, which provides consistent and selective reduction. This converts the previously harmful impurity co-extraction into a beneficial selective separation process where only target metals are extracted
2Manufacturing precision
If additional purification steps are added to remove impurities, then metal purity is improved, but process complexity and time increase
Solution Approach 1:
The patent applies preliminary action by using sodium thiosulfate to selectively extract only the desired metals (lithium and cobalt) in the first place, preventing impurities from entering the solution. This preliminary selective extraction eliminates the need for subsequent purification steps, thereby reducing process complexity while maintaining high metal purity
Solution Approach 2:
The patent takes out only the necessary components (lithium and cobalt) through selective leaching with sodium thiosulfate, leaving impurities behind in the solid residue. This selective extraction approach achieves high purity without requiring additional separation or purification equipment
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
This process effectively reduces impurity co-extraction, enhances metal recovery efficiency, and simplifies subsequent purification steps, leading to high-purity lithium and cobalt extraction.
Implementation Method 1
contacting the combination with a reducing agent so as to form an acid leachate, wherein the reducing agent comprises sodium thiosulfate
Implementation Method 2
adjusting the pH of the acid leachate so as to form a precipitate comprising aluminum
Implementation Method 3
removing Fe(II) and Mn(II) from the acid leachate by contacting the acid leachate with an oxidizing agent
Data Source
AI summary
Processes are described for extracting metals from a combination derived from spent lithium-ion batteries and comprising such metals, a liquid, an acid, and other components.