Lithium-Ion Battery Metal Extraction With Selective Impurity Control
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Solution Overview
Problem
Existing hydrometallurgical processes for recovering metals from lithium-ion battery black mass are prone to carrying impurities like copper and phosphorus along with lithium and cobalt, necessitating additional purification steps.
Innovation Solution
A process involving acid leaching with sodium thiosulfate as a reducing agent, followed by pH adjustment to form aluminum precipitates, and subsequent oxidation of iron and manganese using permanganate anions, to separate and extract lithium, cobalt, nickel, and manganese while minimizing impurity inclusion.
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 copper and phosphorus impurities are carried into the solution
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 copper and phosphorus from entering the solution while maintaining effective cobalt recovery through reduction to Co(II) state.
Solution Approach 2:
Sodium thiosulfate acts as an intermediary reducing agent that selectively reduces cobalt without carrying impurities. The thiosulfate ion serves as a mediating chemical species that facilitates cobalt reduction while leaving copper and phosphorus in the solid phase, thereby separating the reduction function from impurity dissolution.
2Manufacturing precision
If additional purification steps are added to remove copper and phosphorus, then metal purity is improved, but process complexity increases
Solution Approach 1:
The patent extracts or removes the harmful function of hydrogen peroxide that causes impurity co-extraction. By taking out the problematic reducing agent and replacing it with sodium thiosulfate, the source of impurity dissolution is eliminated, making additional purification steps unnecessary and simplifying the overall process.
Solution Approach 2:
The patent converts the potential harm of using a reducing agent that might dissolve impurities into a benefit by selecting sodium thiosulfate, which has the unique property of reducing cobalt while leaving copper and phosphorus in the solid phase. This transforms the reducing agent function into a selective separation mechanism.
3Productivity
If conventional acid leaching is used, then metal extraction is achieved, but impurities are carried along requiring further purification
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 copper and phosphorus from entering the solution while maintaining effective cobalt recovery through reduction to Co(II) state.
Solution Approach 2:
Sodium thiosulfate acts as an intermediary reducing agent that selectively reduces cobalt without carrying impurities. The thiosulfate ion serves as a mediating chemical species that facilitates cobalt reduction while leaving copper and phosphorus in the solid phase, thereby separating the reduction function from impurity dissolution.
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 process effectively reduces impurity co-extraction, enhances metal recovery efficiency, and simplifies subsequent purification steps, resulting in a Li/Co-rich solution ready for further separation and 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
subsequent oxidation of iron and manganese using permanganate anions
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.