Material · draft · confidence 0.9
Generated from the Hyphae knowledge graph. Drafted by
claude-sonnet-4-6
A grade of bituminous coal with the plastic (caking) properties needed to fuse into a coherent coke structure during high-temperature carbonization in the absence of air. Also called metallurgical coal. It is characterized by low ash and sulfur content, controlled volatile matter (typically 26–29 wt% in the blend), and positive plasticity as measured by Gieseler or Audibert-Arnu plastometers. Coking coal is the primary raw material input to cokemaking and is distinct from thermal coal used for power generation.
Common forms
- Run-of-mine coking coal (ROM)
- Washed/beneficiated coking coal (reduced ash)
- Crushed and blended coking coal (80% minus 3 mm; ready for charging)
Common sources
- Australia (Queensland Bowen Basin — world’s largest export source)
- USA (Appalachian coalfields)
- Canada (British Columbia)
- Russia
- Mongolia
Composition
Low-ash, low-sulfur bituminous coal. Volatile matter: 26–32 wt% in prime coking coals; blends typically target 26–29 wt%. Ash content: ideally <10 wt% (Steel Grade I: <15 wt%). Sulfur: <1 wt% preferred to limit sulfur transfer to coke and pig iron. Fixed carbon: 55–80 wt% depending on rank.
Hazards
- Coal dust — fine coal particles during handling and crushing can form explosive dust clouds; respirable coal dust causes coal workers’ pneumoconiosis (black lung disease).
Properties
- plasticity: Coking coals exhibit a plastic or fluid phase when heated to approximately 350–500°C, which allows coal particles to fuse together and form a coherent solid coke structure upon resolidification. Measured by Gieseler fluidity (ddpm) or Audibert-Arnu dilatometry.
- coke_strength: Blend design targets high coke strength after reaction (CSR ≥60 for BF use) and low coke reactivity index (CRI <30).
- maceral_composition: Vitrinite-rich coals are preferred; inertinite-rich coals have less caking ability. Maceral composition influences coke optical texture and CRI/CSR.
Connections
Outgoing
- Has hazard → Coal Dust Explosion — Fine coal dust generated during crushing and handling of coking coal can form explosive clouds; also causes coal workers’ pneumoconiosis.
Incoming
- Requires input ← Cokemaking — Primary raw material; consumed in the process. Blend targeted to 26-29 wt% volatile matter, low ash and sulfur. Crushed to ~80% minus 3 mm before charging.