Pig iron

Pig iron is an intermediate product of the iron industry. it is made by smelting iron ore into a transportable ingot of impure high carbon-content iron as an ingredient for further processing steps. It is the molten iron from the blast furnace, which is a large, and cylinder-shaped, furnace charged with iron ore, coke, and limestone. In the past, charcoal, or anthracite coal have also been used as fuel; charcoal was the traditional fuel from classical times into the mid-1830s, but was difficult to use in blast furnaces. Anthracite iron was being developed concurrently in France, Pennsylvania, and Wales using the newly patented Scottish hot blast technology, and the new blast furnace smelting technology; in large part because each state was experiencing a fuel shortage. The first United States energy crisis was like those in industrially developed Europe — close-in stands of forest had been exhausted because transportation options were limited, so both firewood, and charcoal, for heating, steam production for stationary steam engines in mills, and iron smelting furnaces, was growing scarce and expensive. This situation also inspired the American canal age with investors motivated to build the Schuylkill Canal.

Pig iron has a very high carbon content, typically 3.5–4.5%, along with silica and other constituents of dross, which makes it very brittle, and not useful directly as a material except for limited applications.

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