Reduced Graphite Oxide Worm Particle Production via Spray Drying

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Solution Overview

Problem

Current methods for producing graphite oxide are inefficient, requiring extensive time and larger quantities of reagents, and do not effectively reduce the oxygen content of graphite oxide particles, limiting the production of reduced graphite oxide with high surface area and low energy decomposition.

Innovation Solution

A method involving the introduction of a graphite oxide slurry into a chamber at temperatures greater than 300°C, where the oxidant content is reduced by more than 50% to produce reduced graphite oxide worm particles, utilizing a combination of sulfuric and nitric acids with a chlorate solution, and sparging with a gas to manage chlorine dioxide levels, allowing for simultaneous drying and reduction of graphite oxide particles.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If graphite oxide particles are produced by conventional oxidation methods, then graphite oxide is obtained, but the process requires extensive time and larger quantities of reagents

Engineering Contradiction:
Improveproduction efficiencyVSAvoidreaction time
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The patent changes the chemical parameters of the oxidation process by using a chlorate solution with specific concentration ratios and controlling the water to acid ratio to be less than 0.43:1. These parameter optimizations enable faster reaction kinetics and reduced reagent quantities while maintaining effective graphite oxide production

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent implements continuous sparging of gas through the graphite mixture during the oxidation process to continuously remove chlorine dioxide as it forms. This continuous action prevents back-reactions and maintains driving force for the oxidation process, increasing overall productivity and reducing required reaction time

Inventive Principle:
Principle #20Continuity of useful action

2Quantity of substance

If graphite oxide particles are produced by conventional methods, then oxidation occurs, but the oxygen content is not effectively reduced

Engineering Contradiction:
Improveoxygen contentVSAvoidreduction effectiveness
Core Design Contradiction:
Quantity of substanceVSEase of manufacture

Solution Approach 1:

The patent effectively extracts and removes oxygen from graphite oxide particles through controlled thermal treatment at temperatures greater than 300°C. This extraction process reduces the oxygen content by more than 50% by weight, transforming graphite oxide into reduced graphite oxide with lower oxygen content and reduced decomposition energy

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent merges the drying and reduction steps into a single simultaneous process. By introducing the graphite oxide slurry into a chamber at temperatures greater than 300°C, both drying and reduction occur concurrently, simplifying the manufacturing process while achieving effective oxygen removal

Inventive Principle:
Principle #5Merging (Combining)

3Quantity of substance

If graphite oxide particles are thermally treated to reduce oxygen content, then reduced graphite oxide is produced, but the process requires high temperatures and extended time

Engineering Contradiction:
Improveoxygen contentVSAvoidthermal energy consumption
Core Design Contradiction:
Quantity of substanceVSUse of energy by moving object

Solution Approach 1:

The patent performs preliminary oxidation under optimized conditions to produce graphite oxide with controlled properties before thermal reduction. This preliminary preparation ensures that the subsequent thermal treatment at greater than 300°C is more efficient, requiring less energy and time to achieve the desired oxygen reduction

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent optimizes the thermal treatment parameters by conducting reduction at temperatures greater than 300°C (specifically 300-500°C range) rather than conventional higher temperatures. This parameter optimization reduces energy consumption while maintaining effective oxygen removal, achieving a balance between reduction effectiveness and energy efficiency

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

This method efficiently produces reduced graphite oxide worm particles with a high surface area and low oxygen content, reducing decomposition energy and enhancing production efficiency by minimizing reagent usage and reaction time.

Implementation Method 1

reducing the oxidant content of the graphite particles by greater than 50% by weight to produce reduced graphite oxide worm particles

Methodology Applied
Scientific EffectThermal reduction: Reduction

Implementation Method 2

simultaneous drying and reduction of graphite oxide particles

Methodology Applied
Scientific EffectEvaporation: Evaporation

Implementation Method 3

spraying comprises feeding into a spray nozzle a first stream comprising the graphite oxide particles and a second stream comprising an atomizing gas

Methodology Applied
Scientific EffectAtomization: Aerosol

Implementation Method 4

sparging the graphite mixture while feeding the chlorate solution into the graphite mixture

Methodology Applied
Scientific EffectSparging: Sparging

Data Source

PatentEP3691994B1Process for the production of reduced graphite oxide particles
Publication Date: 2021.12.01 CABOT CORP
  • EP3691994B1 patent drawingFigure 1a~1b
  • EP3691994B1 patent drawingFigure 2
  • EP3691994B1 patent drawingFigure 3A~3C

AI summary

Methods for the production of reduced graphene oxide worm (rGOW) particles. Graphite particles are placed in mixture of nitric acid and sulfuric acid. A supply of chlorate is provided to the graphite reaction mixture while it is agitated by a sparger. The resulting graphite oxide slurry is pumped to a tangential filtration system where it is purified and concentrated. The concentrated slurry is then fed to a high temperature spray dryer where it is simultaneously dried and chemically reduced to produce rGOW particles.