Coke is nearly pure carbon that is produced after diving off the volatile constituents of the coal. Natural Coke is formed when the coal seam is intersected by a volcanic intrusion, which heats it in absence of air. Artificial coke is produced by heating bituminous coal in the absence of oxygen at some 2000°C. Coke has higher heat value than the coal itself and is used to generate extremely high temperatures needed for metal refinery / steel industry. In steel industry, apart from providing required higher temperatures, Coke also serves as a chemical reducing agent to produce pure iron from molten iron ore in a blast furnace.