Graphite Purification via Dry Alkali Treatment and Acid Leaching

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Solution Overview

Problem

The existing wet process for purifying spherical graphite is lengthy and complicated, involving excessive washing and filtration steps, which complicates the purification process.

Innovation Solution

A method involving dry-mixing graphite with metal hydroxide, followed by heat treatment and acid treatment, simplifies the purification process by using solid-phase sodium hydroxide and achieving high purity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If wet process is used for purifying spherical graphite, then high purity can be achieved, but the processing steps become excessively long and complicated

Engineering Contradiction:
ImprovepurityVSAvoidprocessing time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The invention changes the physical state parameter of the washing liquid from liquid (wet process) to gas (steam), transforming the purification mechanism from liquid-phase washing to steam-phase treatment. This parameter change eliminates the need for repeated washing and filtration steps while maintaining high purity removal of impurities such as Si, Al, Fe, and Ca

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention replaces the mechanical washing and filtration system with a thermal field-based steam treatment system. Instead of using liquid flow and physical filtration to remove impurities, the method uses steam heating and thermal effects to achieve purification, thereby simplifying the equipment and process steps

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Manufacturing precision

If wet process with repeated washing and filtration is used, then impurity removal is effective, but the processing complexity increases

Engineering Contradiction:
ImprovepurityVSAvoidprocess complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The invention merges multiple separate purification steps (washing, filtration, drying) into a single integrated steam treatment step. The steam process simultaneously achieves heating, washing, and drying functions that were previously performed by separate operations, thereby reducing process complexity

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The invention extracts and eliminates the filtration step from the purification process by using steam treatment that does not require liquid-phase filtration. The steam process directly removes impurities through thermal effects without generating filtrate that needs to be separated, thereby simplifying the overall process

Inventive Principle:
Principle #2Taking out (Extraction)

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 high-purity graphite with reduced impurity content, such as ash, silicon, and aluminum, through a simplified process that reduces processing time and material agglomeration.

Implementation Method 1

an alkali treatment step of dry-mixing a graphite material and a metal hydroxide and subjecting the mixture to heat treatment

Methodology Applied
Scientific EffectChemical reaction: Chemical Bonding

Implementation Method 2

an acid treatment step of subjecting the alkali-treated graphite material to acid treatment

Methodology Applied
Scientific EffectChemical leaching: Chemical Bonding

Implementation Method 3

subjecting the mixture to heat treatment

Methodology Applied
Scientific EffectThermal energy: Heating

Data Source

PatentEP4696652A1Method of producing purified graphite
Publication Date: 2026.02.18 POSCO FUTURE M CO LTD
  • EP4696652A1 patent drawingFigure 1~2
  • EP4696652A1 patent drawingFigure 3
  • EP4696652A1 patent drawing

AI summary

The present invention relates to a method for purifying graphite, which may comprise an alkali treatment step of dry-mixing a graphite material and a metal hydroxide followed by heat treatment, and an acid treatment step of subjecting the alkali-treated graphite material to acid treatment.