Physical Chemistry on Evaporation Removal of Impurities in Molten Silicon Using Reactive Fluxes

2014 Fiscal Year Final Research Report

• Project/Area Number: 25630335
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Metal making/Resorce production engineering
• Research Institution: The University of Tokyo
• Principal Investigator: MORITA Kazuki 東京大学, 工学(系)研究科(研究院), 教授 (00210170)
• Project Period (FY): 2013-04-01 – 2015-03-31
• Keywords: シリコン / ボロン / 太陽電池 / フラックス / 塩化物 / 精製

Outline of Final Research Achievements

A new boron evaporation removal procss from molten silicon using reactive fluxes was proposed. After confirming the reaction between CaCl2 and B2O3, phase relations for the CaO-SiO2-CaCl2 system was clarified and the boron evaporation removal experiments were carried out with various compositions of slags. As a result,boron in a molten silicon was found to be effectively removed into a gas phase and the most effective condition for the boron removal as well as the reaction mecahnism was clarified.
Through the experimental results and discussion in the present research, mass transfer coefficients and diffusion coefficients of boron in the reactive fluxes were evaluated, and the possibility together with the most effective condition for the propsed boron removal process from molten silicon for solar cell were clarified.

Free Research Field

金属生産工学