To provide a method for reducing a part of Mn included in raw materials, collecting it into a workpiece of a molten steel and besides saving the resource and energy by reducing an amount of slag, though most parts of the Mn included in the raw materials are wasted together with oxide slag in a steelmaking process by using an electric furnace and employing iron scrap as a main raw material.

Raw materials are melted and a general process is performed by normally oxidation-refining the while leaving most of oxidative slag in the furnace. The slag is moved into the ladle together with the molten steel when tapping the molten steel. Simultaneously, a reducing agent is added corresponding to the amount of a low-grade oxide in the slag. Airtight covers are attached on the top and the bottom of the ladle, decompressing the inside; and gas bubbling is performed in the molten steel to reduce, refine and collect Mn in the slag. The molten steel are cast into a slab with a continuous casing method which does not cause central segregation though many parts dephosphorized in the oxidation-refining process are rephosphorized and a P content increases. As a result, an action of impurity P as a harmful element is alleviated, and an adequate alloy can be obtained.

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