In steelmaking, nonmetallic impurities such as P, S, and Si are removed as the corresponding oxides. The

Question:

In steelmaking, nonmetallic impurities such as P, S, and Si are removed as the corresponding oxides. The inside of the furnace is usually lined with CaCO3 and MgCO3, which decompose at high temperatures to yield CaO and MgO. How do CaO and MgO help in the removal of the nonmetallic oxides?