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Why is metallurgical coke important in metalmaking?

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coal utilization Cross-regenerative coke oven. (A) Cross section, showing the alternating arrangement of flue walls and ovens; (B) longitudinal section, showing (left) a series of combustion flues in a single flue wall and (right) part of a long, slotlike oven.

Metallurgical coke is essential in metalmaking because it serves as a critical fuel and reducing agent in processes like iron production. Produced through the high-temperature carbonization of bituminous coal, coke is a solid, carbon-rich residue that provides the necessary structural strength and chemical properties for industrial smelting.12

In blast furnaces, oven coke (typically 40 to 100 millimetres in size) is used globally to smelt iron ore into liquid iron. Similarly, specialized "foundry coke" is used in foundry cupolas to melt iron due to its high strength. Beyond iron production, coke is vital for:13

Ferroalloy production: Used in the manufacture of various alloys.1
Chemical manufacturing: Smaller sizes (10 to 25 millimetres) are employed to produce phosphorus and calcium carbide.13
Sintering: Fine particles known as coke breeze are used to sinter small iron ore particles, preparing them for use in blast furnaces.13

While alternative methods like smelting reduction are emerging due to the high cost of coke ovens, coke remains a cornerstone of traditional metallurgical technology.4