STUDIES ON THE DESULPHURIZATION OF MOLTEN PIG IRON BY MANGANESE (II)

Effeet of Si, P on Mn-S equilibrium in C-Saturated molten iron-Part 1

Abstract

In a previous paper it was shown that the high sulphur potential in carbon-saturated liquid iron resulted in the effective desulphurization by manganese. (Tetsu-to-Hagané vol. 43, 1957 pp. 517 & 535)
In this second report, the effect of silicon and phosphorus addition to carbon-saturated iron melts on the Mn-S equilibrium was investigated.
The results showed that the silicon addition improved desulphurization by manganese in higher silicon range, but on the contrary the phosphorus addition had somewhat reverse effect.
However, since such effects were negligible in their lower contents such as below 2%, it should be especially emphasized that the desulphurization limit of normal blast-furnace pig iron was wholly dependent upon the carbon saturation.
The effect of silicon or phosphorus addition presumably was ascribed to increase or decrease of activity coefficient of the sulphur in those melts, which was estimated referring to the previous data of the experiment on Fe-C^sat-Mn-S system.
The results approximately agreed with those calculated by Wagner's, equation in their lower contents.
Finally, the effect of dissolved sulphur on the solubility of carbon in Fe-C-Si and Fe-C-P melts were discussed.