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How did the finery process convert cast iron into wrought iron?
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iron processing
Iron ore is one of the most abundant elements on Earth, and one of its primary uses is in the production of steel. When combined with carbon, iron changes character completely and becomes the alloy steel.
The finery process was a method used to convert cast iron—specifically pig iron—into wrought iron by removing excess carbon.12
The process involved placing pieces of cast iron onto a finery hearth, where charcoal was burned with a plentiful supply of air. Through the chemical reaction of oxidation, the carbon within the iron was removed. As the carbon content decreased, the melting point of the metal rose, leaving behind a semisolid, malleable mass of iron. This two-stage method became widespread following the adoption of blast furnaces in the 15th century, eventually being superseded by the puddling process in the late 18th century.12