Although graphite electrode particles and graphite petroleum coke are both carbon materials and have similar appearances, their sources, ingredients, processes, and application scenarios are significantly different.
1. Source and definition
Graphite electrode granules:
They are scraps or broken pieces produced during the production or use of graphite electrodes. They are essentially physical fragments of finished electrodes. The original materials are petroleum coke, needle coke, and coal tar pitch (binder), which are made through calcination, molding, graphitization (above 2800°C), and other processes.
Graphite petroleum coke:
It is a product directly from petroleum coke after high-temperature graphitization. Petroleum coke originates from the coking of crude oil refining residue. After calcination (1200°C~1400°C) to remove volatiles, it is converted into artificial graphite through graphitization furnace treatment (above 2800°C). Its essence is the deep processing of raw materials.
2. Composition and structure
Graphite electrode granules:
Composition: mainly carbon (>99%), containing a small amount of ash (metal oxide) and residual sulfur (<0.03%). Due to sufficient graphitization, the structure is highly ordered.
Structure: retain the dense porous structure of the electrode, high mechanical strength, and excellent conductivity.
Graphite petroleum coke:
Composition: carbon content>99%, but sulfur (0.5%~0.03% %), ash (Fe, Si, etc.), and volatile content may be high, and sulfur needs to be strictly controlled to avoid "bulging" defects.
Structure: porous granular, the lattice order is lower than that of electrode fragments, and the true density (2.0~2.1 g/cm³) and resistivity are significantly affected by raw materials and degree of graphitization.
3. Production process
Graphite electrode granules:
No need for independent production, it is a by-product or waste in the electrode manufacturing process (calcination→batch→pressing→baking→graphitization→machining).
Graphite petroleum coke:
Requires a complete independent process:
Petroleum coke calcination (devolatilization at 1200℃~1400℃) → graphitization (recrystallization above 2800℃) → crushing/grinding (such as vertical mill processing to less than 0.075mm).
High sulfur coke needs to add inhibitors (such as sodium carbonate) to prevent graphitization explosion.
| Characteristic | Graphite Electrode Granules | Graphite Petroleum Coke |
| Electrical conductivity | Very high (resistivity ≤ 5μΩ·m) | Medium to high (affected by sulfur/ash) |
| Mechanical strength | High (dense structure after molding) |
Low (porous and fragile) |
| Sulfur content | ＜0.03% | 0.5%-0.03% |
| Thermal stability | Very high (expansion coefficient <1×10⁻⁶/℃) | Medium-high (easy to expand when sulfur content is high) |
5. Application scenarios
Graphite electrode granules:
Carbon enhancer: Rapid carbon enhancement in steelmaking (dissolution rate is better than coke).
Recycled raw materials: Add new electrode ingredients after crushing to reduce costs and increase efficiency.
Conductive filler: Used for refractory materials or battery negative electrodes (requires deep processing).
Graphite petroleum coke:
Electrode aggregate: The main raw material for manufacturing graphite electrodes (accounting for 67±5% of the formula).
Negative electrode material: Lithium battery negative electrode precursor (requires spheroidization/coating treatment).
Carbon enhancer/refractory material: Casting, metallurgy field (high purity grade).
Graphite electrode granules are industrial finished product fragments with stable performance, but limited sources; graphite petroleum coke is a basic raw material with a wide range of use, but requires strict sulfur control and deep processing.
The positioning of the two in the industrial chain is significantly different: electrode granules are recycled and reused materials, while graphite petroleum coke is the core raw material of artificial graphite products. Its production and application directly determine the technical level of the carbon industry.
