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Removal of Phosphorus in Metallurgical Silicon by Rare Earth Elements

Abstract

Removal of phosphorus in metallurgical silicon is one of the crucial steps for the production of solar grade Si feedstock. The possibility of doping rare earth elements for phosphorus removal has in this work been studied both theoretically and experimentally. Thermochemical properties of Ce, Nd, and Pr monophosphides have first been estimated by ab initio thermodynamic simulations based on density functional theory and the direct phonon method. The reliability of the first principles calculations was assessed by coupling with the phase diagram data of the Pr-P system. Equilibrium calculations confirmed the existence of stable rare earth monophosphides in solid silicon. Experimental investigations were then carried out, employing a high temperature resistance furnace. The Ce-doped silicon samples were examined by electron probe micro analyzer and inductively coupled plasma analysis. The efficiency of phosphorus removal by means of rare earth doping was discussed in detail in the paper.

Category

Academic article

Client

  • Research Council of Norway (RCN) / 208363
  • Research Council of Norway (RCN) / NN2615K

Language

English

Author(s)

Affiliation

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

Year

2014

Published in

Metallurgical and Materials Transactions E

ISSN

2196-2936

Publisher

Springer

Volume

1

Issue

3

Page(s)

257 - 262

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