Purification of Metallurgical Silicon for Solar-grade Silicon by Electron Beam Button Melting

Takashi Ikeda, Masafumi Maeda
1992 ISIJ International  
Behavior of various impurities such as carbon, phosphorus, boron, calcium, aluminum, iron and titanium in metallurgical-grade silicon has been investigated during eiectron beambutton melting with various modifications. Carbon, phosphorus, calcium and aluminum were removed by Electron BeamRemelting (EBR) tteatment under 10-2 Pa for 30min. Ninety percent of carbon, 750/0 of aluminum, 890/0 of calcium and 930/0 of phosphorus was removed. The lowest content of these impurities were 15 ppmw C, 470
more » ... re 15 ppmw C, 470 ppmw Al, 150ppmw Ca and 3ppmw P, respectiveiy. First order rate equation was used for the removal of carbon, calcium and aiuminum, and second order equation fit for the dephosphorization. Rate constants for calcium, aluminum and carbon ranged from 0.01 to O.1 min~1. That of phosphorus was from 0.003 to 0.01 ppmw~1 . min~1,
doi:10.2355/isijinternational.32.635 fatcat:qpa4yj56a5h3xnr2qqm6vaqoia