Expandable Graphite is produced from flake graphite by process of oxidation and acid intercalation i.e. graphite intercalation compounding process, expands suddenly and rapidly tens or hundreds time greater in volume when temperature reaches or exceeds a fixed degree which is expansion start temperature, its properties of good flexibility and plasticity made expandable graphite widely applied as sealing material and fire retardant in various industries.
Advantages of Expandable Graphite
Excellent fire proof effect with low material consumption
Free of heavy metals (except EG processed by Sodium dichromate method)
Wide range of applications
Lessen fume formation
Classifying of EG
High Expansion EG: 250~350 cm3/g
Low Expansion EG: 100~240 cm3/g
Sodium dichromate (heavy metal included)
Hydrogen Peroxide (heavy metal free)
Potassium Permanganate (heavy metal free)
Nitric Acid (heavy metal free)
Sulphuric acid method
Nitric acid with low Sulphur content
None Sulphur content
4.Expansion Start Temperature
Low temperature start (120℃~160℃)
Medium temperature start (170℃~220℃)
High temperature start (230℃~260℃)
How To Test Expansion Start Temperature
Weigh accurately 1 gram EG into a measuring glass 50ML and record volume level.
Place the measuring glass into a furnace maintained at fixed temperature ’X’ for 10 mins.
Take out the measuring glass after timing and observe volume change status.
If volume level remains same then adjust temperature ‘X’+10°C, repeat heating and observing in every 10℃ gap till visual change of volume level.
The temperature at visual volume change level is Expansion Start Temperature of this EG
Production Flow Chat of Expandable Graphite
How We Control Quality of Expandable Graphite
We have rigorous quality control on each processing program of oxidating, intercalating, washing and drying etc.
Most advanced testing instruments and state of art processing facilities.
Over 30 years graphite processing experience and more than 20 experienced QC staff.