A new method about purification of metallurgical grade silicon （MG-Si） by a combination of Si-Al solvent refining andgas blowing treatment was proposed. The morphologies and transformation of impurity phases, especially for boron and iron in Si-Al melt were investigated during Ar-H2 gas blowing treatment. The mechanism of boron removal was discussed. The resultsindicate that gas blowing can refine grain size and increase nucleation of the primary Si. Boron can be effectively removed fromMG-Si using the Ar-H2 gas blowing technique during the Si-Al solvent refining. Compared with the sample without gas blowing,the removal efficiency of boron increases from 45.83% to 74.73% after 2.5 h gas blowing. The main impurity phases containingboron are in the form of TiB2, AlB2 and VB compounds and iron-containing one is in the form of β-Al5FeSi intermetallic compound.Part of boron combines [H] to transform into gas BxHy （BH, BH2） and diffuses towards the surface of the melt and is volatilized byAr-H2 gas blowing treatment under electromagnetic stirring.
