Graphite Production from Upgraded Coal via Multi-Stage Thermal Processing
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Solution Overview
Problem
Natural coal sources, particularly low-rank coals, have undesirable properties like low fixed carbon concentration, high oxygen content, and high ash content, making them unsuitable for energy generation and graphene production, and the demand for graphite for lithium-ion batteries exceeds the supply of natural graphite resources.
Innovation Solution
A method involving upgrading coal through cleaning and reacting it with oxidizable inorganic metallic agents or reducing agents, followed by carbonization and graphitization, to produce carbonized upgraded coal with reduced ash and oxygen content, resulting in high-quality graphite with specific microstructures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If natural graphite resources are used to meet the growing demand for graphite in lithium-ion batteries, then the supply is insufficient and cannot meet the rapidly growing demand, but using alternative sources like natural coal requires extensive processing to achieve suitable quality
Solution Approach 1:
The patent applies parameter changes by systematically adjusting temperature, pressure, and chemical composition parameters during the carbonization and graphitization processes. The multi-stage heating process with specific temperature ranges (500-700°C, 900-1100°C, 1500-1600°C, and final graphitization at 2500-3000°C) transforms coal into graphite with controlled microstructures, achieving both high productivity and reliable material quality.
Solution Approach 2:
The patent creates composite material structures by forming specific graphite microstructures (croissant graphite, 3D graphene stacks, graphulerenite) from processed coal. These composite structures combine the carbon content benefits of coal with the desired graphical properties, producing a material that meets lithium-ion battery requirements while utilizing abundant coal resources.
2Ease of manufacture
If low-rank coal is used directly for energy generation or graphene production, then the process is simpler and faster, but the low fixed carbon concentration, high oxygen content, and high ash content make it unsuitable for high-value applications
Solution Approach 1:
The patent applies preliminary action by performing extensive pre-processing of the coal before the main carbonization and graphitization steps. This includes cleaning the coal to remove impurities, adjusting its chemical composition to reduce oxygen and ash content, and preparing it in a controlled manner before subjecting it to high-temperature treatment. This preliminary preparation ensures that the final graphite product achieves the required manufacturing precision and carbon content quality.
3Manufacturing precision
If coal is extensively processed through cleaning and chemical reactions to upgrade its quality, then the fixed carbon concentration increases and ash content decreases, but the manufacturing process becomes more complex
Solution Approach 1:
The patent merges multiple processing functions into an integrated system. The cleaning, chemical treatment, carbonization, and graphitization steps are combined into a coordinated multi-stage process where each stage builds on the previous one. This merging approach achieves high fixed carbon concentration (97-99.9%) while managing overall process complexity through systematic integration rather than separate discrete operations.
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 produces graphite with a high carbon content and controlled microstructures, such as croissant graphite and 3D graphene stacks, which is more cost-effective and efficient for applications in lithium-ion batteries and other energy storage solutions, overcoming the limitations of natural graphite supplies.
Implementation Method 1
heating the upgraded coal in an inert environment, to form a carbonized upgraded coal
Implementation Method 2
graphitizing carbonized upgraded coal, to form the graphite. The graphitizing includes heating the carbonized upgraded coal, the heating including heating to a first graphitization temperature for a first graphitization duration
Data Source
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AI summary
A method of forming graphite includes carbonizing an upgraded coal, to form a carbonized upgraded coal. The method also includes graphitizing the carbonized upgraded coal, to form the graphite.