Hierarchy classification:

1. top of the aat hierarchies
2. Materials Facet
3. Materials (hierarchy name)
4. materials (substances)
5. [materials by composition]
6. organic material
7. bituminous material
8. modified bituminous material

Anotations

Scope note:

The dark, porous, carbonized residue left after the destructive distillation of bituminous coal, petroleum or coal tar pitch. Coal can be converted to coke by heating it in an airless oven to drive off all volatile components. Coke was once made in large quantities as a byproduct when coal was burnt to produce methane. Coke is useful in metallurgy because it burns hotter than coal; it is used primarily as a fuel or as a reducing agent in the iron and steel industry, primarily in blast furnaces. The process for using coke in smelting was developed in the 17th century. In the 18th and 19th centuries coke aided in the expansion of the cast iron and steel production. Coke can also be converted to graphite.