What Is the Difference Between Thermal and Metallurgical Coal?

Thermal and metallurgical coal are two different types of coal that are used in a variety of applications. The main differences between thermal and metallurgical coal are their calorific value, carbon content, volatile matter content, ash content and caking properties.

Thermal coal, also known as steam coal, is used for power and heat generation. In electricity generation, thermal coal is burned in boilers to produce steam which turns turbines that drive generators. This type of coal has a lower energy density than metallurgical coal and requires significantly more air flow to burn efficiently. It typically contains a higher sulphur content than metallurgical coal due to its low carbon content. 

Metallurgical coal, also known as coking coal or coke, is used mainly in steel production. The process of making steel involves heating metallurgical coal to very high temperatures until it chemically changes into coke and then injecting the coke into a blast furnace filled with iron ore and limestone. 

In general, thermal coal tends to be more expensive than metallurgical coal due to its higher energy content and the fact that it must be transported over long distances from mine to power plants.