Online ISSN : 1883-2954
Print ISSN : 0021-1575
ISSN-L : 0021-1575
Phosphorus Distribution between Mn-Si Melts and CaO-SiO2-MnO-CaF2 Slags
Eiji AIDAMin Dong JOONNobuo SANO
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1988 Volume 74 Issue 10 Pages 1931-1938


Experiments were carried out to investigate the equilibrium distribution ratio of phosphorus (LP) between CaO-SiO2-MnO-CaF2 melts and carbon saturated Mn-Si alloy as a function of oxygen partial pressure, alloy and slag compositions at 1300°C. The results demonstrate that LP increases with increasing the basicity of slag, silicon concentration and oxygen partial pressure. In order to understand quantitatively the effect of silicon concentration on LP, the phosphorus activity coefficient in Mn-Si alloys was measured and the interaction parameter, εPSi in Mn at 1300°C was found to be 10.7.
The CaO equivalent of MnO for dephosphorization was found to be 0.4 ± 0.1 in terms of weight percent.
By measuring the manganese activity in Mn-Si alloy, the activity coefficient of MnO in the range of the present slag composition was calculated to be in the range of 0.42 to 0.62.
The critical oxygen partial pressure between the stability of phosphate and phosphide in this slag system was about 10-18.4 atm at 1300°C.

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