Spent Battery Graphite Purification for Battery-Grade Recovery
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Solution Overview
Problem
Current recycling processes for lithium-ion battery graphite are hindered by the presence of contaminants, particularly metal impurities and silica, which prevent the production of battery-grade graphite, and there is a need for a cost-effective and environmentally sustainable solution.
Innovation Solution
A process involving the separation of graphite from black mass, followed by pre-purification using aprotic dipolar solvents and heat treatment, and further purification through methods like ultra-high temperature treatment and carbon coating to achieve high purity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional recycling processes are used to separate graphite from black mass, then graphite can be recovered, but the graphite contains excessive impurities (over 5%) including metal contaminants, organic electrolyte remnants, and silica, preventing it from meeting battery-grade purity requirements
Solution Approach 1:
The purification process is divided into multiple sequential stages: initial separation of graphite from black mass, pre-purification to remove bulk contaminants, and final purification to achieve battery-grade purity. This segmentation allows each stage to target specific impurity types, systematically reducing contamination from over 5% to below 99.9% purity levels without requiring a single overly complex process
Solution Approach 2:
Pre-purification steps are performed before final purification to remove bulk contaminants such as metal particles, organic electrolyte remnants, and silica. This preliminary action reduces the impurity load beforehand, making the subsequent final purification step more effective and efficient in achieving the required battery-grade purity standards
2Manufacturing precision
If multiple purification steps are implemented to achieve high purity graphite, then battery-grade graphite can be produced, but the process becomes more complex and costly
Solution Approach 1:
The process utilizes changes in physical and chemical parameters at different purification stages. Pre-purification employs parameters such as density differences and magnetic properties to remove bulk contaminants, while final purification uses controlled chemical reactions and filtration parameters to achieve battery-grade purity. These parameter changes enable effective purification without requiring excessively complex process equipment
Solution Approach 2:
The process converts harmful impurities into removable byproducts. Metal contaminants are transformed into separable magnetic particles or dissolved residues, organic electrolyte remnants are degraded into removable compounds through thermal treatment, and silica is converted into separable precipitates. This approach simplifies the overall manufacturing by turning complex contamination removal into systematic conversion and separation operations
3Quantity of substance
If traditional smelting and acid leaching processes are used, then metal elements can be recovered, but graphite is not recovered and significant material loss occurs
Solution Approach 1:
The process extracts graphite from black mass through physical separation methods such as density-based separation and magnetic separation, rather than through smelting or acid leaching that would dissolve or destroy the graphite structure. This extraction approach preserves the graphite material while still enabling recovery of metal elements from the remaining black mass, achieving both material conservation and environmental sustainability
Solution Approach 2:
The process selectively discards harmful impurities (metal contaminants, organic residues, silica) while recovering and preserving the valuable graphite material. By separating graphite early in the process and applying targeted purification steps, the method recovers graphite that can be reused in battery manufacturing, thereby reducing the need for virgin graphite extraction and minimizing environmental impact
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 achieves graphite purity exceeding 99.9%, suitable for lithium-ion batteries, with improved efficiency and reduced environmental impact.
Implementation Method 1
pre-purifying the separated graphite by means of treatment with an aprotic dipolar solvent
Implementation Method 2
pre-purifying the separated graphite by means of treatment with an aprotic dipolar solvent and/or heat treatment
Implementation Method 3
pre-purifying the separated graphite by means of treatment with an aprotic dipolar solvent and/or heat treatment
Implementation Method 4
further purification through methods like ultra-high temperature treatment
Implementation Method 5
further purification through methods like ultra-high temperature treatment and carbon coating
Data Source
AI summary
Provided herein is a process for recovery of graphite from black mass, comprising the steps of: initially separating the graphite from other components of the black mass; pre-purifying the separated graphite by means of treatment with an aprotic dipolar solvent and/or heat treatment, and sorting by particle size, shape and/or density; and further purifying the pre-purified graphite.