Blast Furnace Projects

Extracting Iron

• Europeans developed blast furnaces so they could more efficiently separate -- or extract -- iron from iron ore, the mineral that contains the pure metal. You can replicate the extraction process by filling a blast furnace with iron ore, such as the iron oxide magnetite or hematite; flux, which removes impurities; and coke. Coke is a solid, carbon-based fuel that is made by heating coal in an air-free environment. When exposed to the pressurized air of a blast furnace, the coke reacts and forms carbon dioxide. This reaction produces significant heat and causes the pure iron inside the ore to melt. The molten iron then trickles down to the furnace’s bottom, where you can collect it.

Making Pig Iron

• For a traditional blast furnace project, you can allow the molten iron that you extract to flow directly from the furnace’s base into a trough filled with sand. By setting up smaller troughs that feed off this main trough, you can collect the molten iron and allow it to harden into pig iron. Pig iron consists of simple, oblong blocks that you can store and melt down later for casting. The “pig” in pig iron stems from the fact that the configuration of the troughs resembles suckling piglets.

Casting Iron

• As an alternative to creating pig iron with a blast furnace and then remelting that iron for casting, you can cast iron directly from the blast furnace. The casting process is similar to the process for making pig iron, with the only difference being that you collect the molten iron in a mold instead of a trough. For a blast furnace project, you could use a mold to cast something such as an iron pot, pan or bell.

Creating Slag

• By adding limestone flux to a blast furnace during the iron extraction process, you can create slag. Slag is stony waste matter that accumulates on molten iron at the bottom of the blast furnace. You can drain the slag and use it as an ingredient in cement. Slag forms as a result of the furnace’s heat changing limestone into calcium oxide. The calcium oxide reacts with silicon dioxide -- which is present in iron ore -- and produces calcium silicate, the primary component of slag.