Expanded Graphite
| HS Code | 459428 |
| Appearance | black, gray, or silver flaky powder |
| Density | relatively low |
| Thermal Conductivity | high |
| Electrical Conductivity | high |
| Chemical Stability | good, resistant to many chemicals |
| Lubricity | excellent |
| Expandability | can expand significantly when heated |
| Adsorption Capacity | high for some substances |
| Temperature Resistance | can withstand high temperatures |
| Mechanical Strength | relatively good in certain forms |
As an accredited Expanded Graphite factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | acking Expanded Graphite, industrial grade uses kraft paper bag with inner film, tied with rope; high-end grade uses aluminum foil bag, outer box is shockproof, all marked with "lightweight". |
| Storage | acking Expanded Graphite, industrial grade uses kraft paper bag with inner film, tied with rope; high-end grade uses aluminum foil bag, outer box is shockproof, all marked with "lightweight". |
| Shipping | Transport Expanded Graphite in open trucks, cover with mesh cloth to prevent blowing, load and unload lightly, prohibit heavy pressure, and collect as soon as it is scattered. |
Competitive Expanded Graphite prices that fit your budget—flexible terms and customized quotes for every order.
For samples, pricing, or more information, please call us at +8615380400285 or mail to sales2@liwei-chem.com.
We will respond to you as soon as possible.
Tel: +8615380400285
Email: sales2@liwei-chem.com
Historical Development
Ancient graphite was mostly used for writing and ink making. In recent times, its expansion characteristics were discovered, and craftsmen obtained Expanded Graphite through acidification and high temperature treatment. Initially, the expansion multiple was low, but after four years of process optimization, it can now expand dozens of times, becoming a good material for fireproof sealing and flame retardancy.
Product Overview
Expanded Graphite is a gray-black porous flocculent, light, odorless, insoluble in water and organic solvents, resistant to high temperature and corrosion, expands in fire to seal gaps, has both flame retardancy and thermal conductivity, and is mostly used in fireproof sealing strips, flame retardant coatings, and battery materials.
Physical & Chemical Properties
Expanded Graphite has a density of 0.05-0.15g/cm³, an expansion multiple of ≥250ml/g, high temperature resistance of 3000℃, stable chemical properties at room temperature, non-flammable, good conductivity and adsorption, smooth feel, and easy to disperse.
Technical Specifications & Labeling
Expanded Graphite, carbon content ≥98%, moisture ≤0.5%, expansion multiple 250-300ml/g, particle size 0.15-1mm, the label must be written with the full name Expanded Graphite, with an expansion multiple test report and purity certificate attached.
Preparation Method
Expanded Graphite is prepared from natural flake graphite, which is acidified with a mixture of nitric acid and sulfuric acid, washed with water until neutral, dried and expanded at high temperature to obtain Expanded Graphite. The acidification concentration and expansion temperature are controlled to ensure quality.
Chemical Reactions & Modifications
Expanded Graphite does not burn at high temperatures, but expands rapidly when exposed to fire to form an insulating carbon layer, isolating oxygen and heat. It has significant synergy when combined with other flame retardants. It does not react with acids and alkalis at room temperature and has good chemical stability.
Synonyms & Product Names
Expanded Graphite is also known as "expanded graphite", but in trade and technical documents, the full name Expanded Graphite must be written to indicate its expansion characteristics.
Safety & Operational Standards
When operating Expanded Graphite, you must wear a dust mask, work in a ventilated place to avoid inhalation of dust, wash your hands after work, and prohibit open flames in the storage area. It should be stored separately from oxidants.
Application Area
Expanded Graphite is mostly used for fireproof door and window seals, cable fireproof plugging, and flame-retardant coatings. It is widely used in the fields of petroleum, chemical industry, and construction. It can also be used as a battery electrode material and adsorbent, with diverse functions.
Research & Development
Artisans are researching the surface modification technology of Expanded Graphite to improve its compatibility with polymer materials. At the same time, they are developing high expansion multiple products, exploring applications in high-end fields such as aerospace and new energy, and expanding its functional boundaries.
Toxicity Research
Expanded Graphite itself is non-toxic, with an oral LD50 of rats > 10000mg/kg. Long-term inhalation of dust may cause lung deposition. It is non-teratogenic and non-carcinogenic. It can be safely operated with protective measures.
Future Prospects
With the development of fire safety and new energy industries, the demand for Expanded Graphite will increase by 15% annually. Its production process will develop in the direction of acid-free and environmentally friendly, or it may play a key role in the fields of new energy batteries and efficient sealing, and its application prospects are broad.
Where to Buy Expanded Graphite in China?
As a trusted Expanded Graphite manufacturer, we deliver:
Factory-Direct Value: Competitive pricing with no middleman markups, tailored for bulk orders and project-scale requirements.
Technical Excellence: Precision-engineered solutions backed by R&D expertise, from formulation to end-to-end delivery.
Whether you need industrial-grade quantities or specialized customizations, our team ensures reliability at every stage—from initial specification to post-delivery support.
As a leading Expanded Graphite supplier, we deliver high-quality products across diverse grades to meet evolving needs, empowering global customers with safe, efficient, and compliant chemical solutions.
How to control the expansion multiple when preparing Expanded Graphite?
This material is made of natural flake graphite (carbon content 99%, particle size 50 mesh) as raw material, immersed in a mixture of concentrated sulfuric acid and nitric acid (volume ratio 3:1), solid-liquid ratio 1:5, and reacted at room temperature for 2 hours, like pickled meat, so that acid groups are embedded between graphite layers. Wash with water to a pH value of 5-6, centrifugal dehydration, and dry at 80℃ to obtain expandable graphite. Place it in a muffle furnace and heat it instantly at 300℃ for 30 seconds. The gas between the graphite layers expands to obtain Expanded Graphite. The expansion multiple needs to be controlled at 200-300mL/g, like popcorn with a certain degree of puffiness. If it is too high, it will be fragile, and if it is too low, the flame retardancy will be poor. After expansion, it is screened and 50-200 mesh particles are selected, with ash content <1% and fixed carbon >98%, which are excellent products for sealing and flame retardancy.
What is the application of Expanded Graphite in sealing materials?
This product is added to nitrile rubber at a dosage of 30%, mixed with carbon black and vulcanizer, and rolled into a sealing gasket with a Shore hardness of 70A and a compression rebound rate of >45%, which meets the GB/T 19228.3 standard. At a high temperature of 200°C, the gasket still maintains good elasticity, and the leakage rate is <1×10⁻⁶Pa・m³/s, which is much lower than the 1×10⁻⁴ of asbestos gaskets. It is used for flange sealing and can withstand 1000 hours of immersion in kerosene and engine oil, with a volume change rate of <5%. Therefore, it is widely used in petrochemical pipelines and automobile engine seals. It can prevent medium leakage and has high temperature resistance. It is an environmentally friendly material that replaces asbestos.
What is unique about the flame retardant mechanism of Expanded Graphite?
This material does not burn when exposed to fire, and its volume is stable at high temperatures. Its porous structure absorbs heat like a sponge, making it difficult for the substrate temperature to rise to the ignition point. In polymers, expanded graphite flakes can block oxygen from contacting combustibles, such as building walls to block fires, while inhibiting molten dripping. When compounded with APP for polyethylene, a "graphite-carbon layer" composite barrier is formed during combustion, and the oxygen index is increased to 35%, 8 percentage points higher than when APP is used alone. Its flame retardancy is a physical effect, does not produce toxic gases, and the smoke density level is reduced by 40%, so it is suitable for flame retardant materials in crowded places such as subways and hospitals, taking into account safety and environmental protection.
What is the difference between the performance of Expanded Graphite and ordinary graphite?
Compared with ordinary graphite, Expanded Graphite has a specific surface area 100 times larger, reaching 50m²/g, and has a stronger adsorption capacity. The adsorption of organic vapor can reach 80% of its own weight. In terms of mechanical properties, its compression strength reaches 0.5MPa and the rebound rate is 45%, while ordinary graphite is brittle and inelastic. In terms of flame retardant efficiency, adding 5% can make polypropylene reach UL94 V-1 level, while ordinary graphite requires 15% because the barrier effect of the expanded sheet is more significant. Although the cost is 5 times higher than that of ordinary graphite, its multifunctionality (sealing, flame retardant, adsorption) makes it more cost-effective and suitable for high-end fields.
What are the specifications for processing and storage of Expanded Graphite?
This product is packaged in kraft paper bags, 20kg per bag, lined with PE film to prevent moisture absorption, and covered with woven bags after the bag mouth is tied tightly. Store in a dry warehouse with a relative humidity of less than 60%, avoid mixing with oxidants and strong acids, and stay away from fire sources, because it is easy to raise dust when drying, but it does not self-ignite. Wear a dust mask during processing, install a dust removal system in the workshop, and the dust concentration is less than 8mg/m³. When mixed with rubber, it must be plasticized in an open mill first, and then gradually added. The temperature must be controlled below 80℃ to prevent rubber aging. If the material clumps after long-term storage, it can be loosened by manual kneading without affecting the performance, ensuring it can be used at any time.
