Product

Anthracite is the highest-rank coal with 80-95% fixed carbon content, characterized by its hard, dense structure (Mohs hardness 2.75-3), semi-metallic luster, and clean-burning properties. It has extremely low volatile matter (typically ~5%), minimal moisture content (<15%), and very low sulfur (~0.6%) and ash levels.

Figure 1 — Comparison of different type of coals

With a gross calorific value of 6,200-7,900 kcal/kg (26-33 MJ/kg) on a mineral-matter-free basis, anthracite produces high heat with minimal smoke or particulate emissions. The coal burns slowly with a characteristic blue flame at temperatures around 900°F (480-500°C) and is non-agglomerating, meaning it does not coke or fuse together during combustion. Its jet-black appearance, high thermal conductivity, and resistance to self-ignition make it distinctive, though its slow ignition and high density limit its use in pulverized coal-fired power plants.

Figure 2 — Formation of coal

References

1. Wikipedia. Anthracite (page version: Jan 3, 2026)
2. Satiendra. Anthracite Coal (Sep 8, 2018). Ispat Guru
3. Hussein A.K.. Characteristics of Coal and Anthracite. Innov Ener Res 2021, 10:10. ISSN: 2576-1463
4. Lasky J.. Anthracite (2023). EBSCO Information Services, Inc.
5. Kopp O.C.. anthracite. Britannica (page version: Apr 4, 2025)