A blast furnace is a large industrial structure used to produce iron from iron ore. It operates by combining iron ore, coke (a form of carbon), and limestone at high temperatures. The coke burns to generate heat, while the limestone helps remove impurities, resulting in molten iron that can be further processed. The process involves blowing hot air into the furnace, which fuels the combustion of coke. As the materials inside the furnace melt, they separate into layers, allowing the molten iron to be tapped from the bottom. This method is essential for producing steel, which is a key material in construction and manufacturing.