Effect of Temperature on Segregation Coefficients of Impurities in Phosphorus

The present work is focused on the relationship between effective segregation coefficient keff and temperature of melting zone for purification of phosphorus by zone melting method. Values of keff at four temperatures of melting zone are obtained for zone pass n=1 at travel velocity of molten zone v=5×10−3 m·h−1 and initial impurity concentration C0≤10 μg·g−1. lnkeff is a linear function of 1/T. The keff values of Al, Ca, Cr, Fe, Cd and Sb increase with temperatures while that of Mg is almost constant. The purification is acceptable at lower temperature of melting zone such as 323 K. The variations of enthalpy and entropy between impurities and phosphorus in the liquid and solid phases are also presented.