Blast furnace practice: principal function of coke in the burden Choose the statement that best describes the role of coke in a blast furnace charge. Select the correct option.

Concept
Coke serves as both fuel and reducing agent in the blast furnace. It combusts to supply high temperatures and generates CO, which chemically reduces iron oxides to metallic iron. Flux (e.g., limestone), not coke, combines with impurities to form slag.

Option analysis
• (c) is correct: coke provides heat and participates in reduction via CO.
• (a) “controls grade” is not its primary defined role.
• (b) coke is not iron-bearing ore.
• (d) slag formation is mainly via fluxes reacting with gangue.

Final Answer
Supplies heat to reduce the ore and melt the iron