Technical reference: graphite‑mill.com industrial processing data for artificial graphite anode precursor.
Green coke (raw petroleum needle coke) for lithium‑ion artificial graphite anode comes from coker output in large block form. Multi‑stage pre‑crushing is required before drying and fine grinding‑shaping.
Mainstream industrial pre‑crushing particle size
- Primary coarse crushing (Jaw crusher / hammer crusher)
Raw bulk green coke is reduced to 10–25 mm. This step breaks big lumps, protects downstream equipment and improves feeding stability. - Secondary pre‑crushing (before entering fine‑grinding host)
Target maximum particle size: ≤ 5 mm, this is the critical feed size for mechanical impact mill for green coke processing.
- Typical range: 1 mm ~ 5 mm; D50 approx. 2‑3 mm after secondary pre‑crushing.
- Moisture requirement before fine grinding: green coke moisture < 10 % to avoid caking and mill blockage.
Notices: Green coke cannot be fed directly into ultra‑fine mill with particles larger than 5 mm. Oversized feed leads to heavy rotor load, low yield, unstable particle‑size distribution and accelerated metal wear contamination.
Alternative process windows
- For some compact production lines: secondary pre‑crushing target ≤ 3 mm, which reduces grinding load and generates fewer over‑fine dust fractions.
- Do NOT confuse with calcined coke: calcined coke pre‑crushing is commonly controlled ≤ 10 mm, different from green coke requirements.
Process flow sequence
Green coke lump → primary coarse crushing (10‑25 mm) → secondary pre‑crushing (≤ 5 mm) → screening → drying → fine grinding‑shaping → classification → carbon coating → graphitization.
Quick comparison table
| Material | Pre‑crushing max feed size before fine mill | Remarks |
|---|---|---|
| Green coke (needle coke, anode grade) | ≤ 5 mm (1‑5 mm preferred) | Medium hardness, high volatile content, strictly control feed size |
| Calcined coke | ≤ 10 mm | Higher hardness, roller mill suitable |
