This work was carried out to obtain the knowledge of the dephosphorization ability of calciumsiliside. Electrolytic iron was melted in magnesia crusibles in a flow of argon gas. After melted down, the mixture of calciumsilicide and calciumfluoride was added on the surface of the molten iron as flux. The results obtained are summarized as follows.
1) In the case of the single addition of calciumsilicide, the phosphorus concentration decreased only a little. In the case of the mixture of calciumsilicide and calciumfluoride, however, the decreasing of the phosphorus concentration was markedly observed.
2) The degree of dephosphorization increased, as the amount of calciumsilicide in the flux increased.
3) The rate of dephosphorization increased, as the amount of calciumfluoride in the flux increased.
4) As the initial carbon concentration increased, the degree of dephosphorization decreased.
5) Spheroidal calciumphosphides were observed in the flux on the inside surface of the magnesia crusible.
