The management and exploitation of phosphorus in bloomery iron

Phosphorus was a very common alloying element in ancient iron. Though phosphoric iron has been increasingly studied by archaeometallurgists in recent decades, little work has been published on how preindustrial smelters and smiths may have controlled and utilized phosphorus in their iron. This paper briefly summarizes our experience in controlling the phosphorus content of bloom iron. Part one deals with controlling phosphorus levels through various smelting parameters, including the speed, temperature, and length of the smelt, the proper management of slag, and the addition of calcium. Part two discusses the removal of phosphorus after smelting. Part three presents some observations on the positive aspects of working with phosphoric bloom iron.