Blast Furnace No. 1. The large circular pipe fed air from the blast stoves into the base of the furnace through eight openings. This caused the reaction of coke, 2C + O2 => 2CO, and the reduction of iron, Fe2O3 + CO => 2FeO + CO2 and FeO + CO => Fe + CO2. The molten iron flowed into a pool, and limestone, serving as a flux, combined with impurities to form a slag that floated on the iron. The CO, furnace gas, was driven off at the top, and reused as fuel. The molten iron flowed into a series of troughs that fed into casts for bars of raw iron, the resemblance to pigs feeding at a trough gave it the name "pig iron".
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