Graphite Purification via Acid-Base Leaching Sequence

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Solution Overview

Problem

Existing methods for producing purified graphite are time-consuming and require a large number of steps, leading to inefficiencies.

Innovation Solution

A three-step process involving acidic leaching, basic digestion, and subsequent leaching with water, optimized for reduced effort, achieves high purity (over 99.95%) by using specific acid and base concentrations and temperatures, along with controlled filtration and washing steps.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If multiple acidic and basic leaching steps are used, then purification quality is improved, but process time and complexity increase

Engineering Contradiction:
Improvepurification qualityVSAvoidprocess time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent combines multiple acidic and basic leaching steps into an optimized sequence where acidic leaching (20-120 minutes) is followed by basic digestion (30-150 minutes at 350-550°C), then water leaching (30-180 minutes), and a second acidic leaching (30-240 minutes). This merged approach achieves over 99.95% purification while reducing total processing time compared to conventional separate treatments.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent optimizes process parameters including temperature ranges (350-550°C for basic digestion), time durations (20-120 minutes for first acidic leaching), and reagent concentrations to achieve high purification efficiency. By carefully controlling these parameters, the process reduces total treatment time while maintaining superior purification quality of over 99.95%.

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If multiple filtration and washing steps are performed, then purification quality is improved, but process complexity increases

Engineering Contradiction:
Improvepurification qualityVSAvoidprocess complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent segments the purification process into distinct stages: first acidic leaching with filtration, basic digestion with filtration, water leaching with filtration, and second acidic leaching with filtration. Each segment produces a specific residue and filtrate, allowing systematic purification while maintaining manageable process complexity through clear separation of operations.

Inventive Principle:
Principle #1Segmentation

3Productivity

If basic digestion is performed at high temperature, then purification efficiency is improved, but energy consumption increases

Engineering Contradiction:
Improvepurification efficiencyVSAvoidenergy consumption
Core Design Contradiction:
ProductivityVSUse of energy by stationary object

Solution Approach 1:

The patent specifies basic digestion at temperatures of 350-550°C for 30-150 minutes, optimizing the balance between purification efficiency and energy consumption. This parameter range achieves rapid purification of basic impurities while controlling energy input compared to conventional high-temperature treatments.

Inventive Principle:
Principle #35Parameter changes

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 excellent cleaning performance with reduced effort, producing graphite with purities up to 99.99% and 99.95% through optimized reaction times and conditions.

Implementation Method 1

First acidic leaching of a graphite starting material with an acid at a temperature of no more than 100 °C

Methodology Applied
Scientific EffectAcidic leaching: Chemical Bonding

Implementation Method 2

basic digestion of a mixture of a base and the first washed residue at a temperature in the range of 350 °C to 550 °C

Methodology Applied
Scientific EffectBasic digestion: Chemical Bonding

Implementation Method 3

leaching of the mixture with water for a third reaction time of 30 to 180 minutes

Methodology Applied
Scientific EffectLeaching with water: Solvation

Data Source

PatentEP4508008B1Method for producing purified graphite
Publication Date: 2026.01.28 DORFNER ANZAPLAN GMBH
  • EP4508008B1 patent drawingFigure 1
  • EP4508008B1 patent drawingFigure 2

AI summary

The invention relates to a method for producing purified graphite, having the following steps: - carrying out a first acid leaching process on a graphite starting material using an acid at a temperature of maximally 100 °C for a specified first reaction duration, - carrying out a first filtration process in order to produce a first residue and a first filtrate, - washing the first residue using distilled water, - carrying out a base decomposition process on a mixture of a base and the first washed residue at a temperature ranging from 350 °C to 550 °C for specified second reaction duration, - carrying out a leaching process on the mixture using water for a specified third reaction duration, - carrying out a second filtration in order to produce a second residue and a second filtrate, - washing the second residue using distilled water, - carrying out a second acid leaching process on the washed second residue using an acid at a temperature of maximally 100 °C for a specified fourth reaction duration, - carrying out a third filtration process in order to produce a third residue and a third filtrate, and - washing the third residue using distilled water.