In most of the cases, the pig iron produced in Non Integrated Mills doesn't go through any additional refining process after leaving the blast furnace. Thus, the amount of some unwanted elements in it, like phosphorus, is solely dependent on raw materials quality. As the production process of pig iron in blast furnaces offers no thermodynamical condition to the retention of phosphorus by the slag, the whole amount of it, entering through charcoal and iron ores, will be forwarded to the pig iron. The difficult availability of a high quality raw material free of phosphorus, together with a higher market value of phosphorus free pig iron, lead MGS - Minas Gerais Siderurgia Ltda. to install in its facilities, in the city of Sete Lagoas, a pig iron ladle dephosphorization process. In order to avoid environmental problems a Lime (CaO) based process with submerged lance was chosen together with oxygen blow on the surface of the bath. This paper describes the dephosphorization process and some operational results. It can be technically concluded that the pig iron lime based dephosphorization process is feasible and that operational optimizations are still necessary which will be only achieved with a proper process control system.
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