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Kinetic study of vacuum evaporation of elements from ternary melts; case of dilute solution of P in Si-Al melts

Abstract

This research is devoted to study phosphorus removal from Si-Al alloys by vacuum refining of the ternary system of dilute solutions of P in Si-20 wt%Al. The experiments were carried out in an induction furnace and after the refining process, the melt was characterized by ICP-MS technique to trace the concentration change of the volatile elements. The experimental results show that P removal from Si-Al-P melts takes place faster compared to Si-P melts and Al evaporates during the vacuum refining as well. The empirical kinetics of P and Al evaporation is discussed and the apparent activation energy for P and Al evaporation from Si-Al melts is obtained as and respectively. Results show that the composition of the melt changes continuously during the refining process due to rapid Al evaporation. In order to investigate the evaporation kinetics of the melt constituents, we developed a numerical approach by applying the Hertz-Knudsen-Langmuir equation for evaporation. This approach can be applied to model the evaporation of the melt constituents in a ternary system whose composition changes during the vacuum refining process. The model is validated with performed experimental results and it can be applied to discuss the effect of temperature, pressure, initial melt composition on the time of vacuum refining.
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Category

Academic article

Language

English

Author(s)

  • Arman Hoseinpur Kermani
  • Kai Tang
  • Jafar Safarian

Affiliation

  • SINTEF Industry / Metal Production and Processing
  • Norwegian University of Science and Technology

Year

2019

Published in

Separation and Purification Technology

ISSN

1383-5866

Volume

235

View this publication at Norwegian Research Information Repository