Separation of Pure Silicon from Al-Si Alloy Melts

Abstract

Pure silicon can be obtained from Al-Si alloys by a combination of solvent refining and centrifugation. Primary silicon crystals are separated in the form of a foam after centrifugation. A vertical centrifugal separator is used which needs no more effort for further separation since each part of the high and low silicon content is divided automatically into two pieces after centrifugation. This centrifugal method does not use the density difference between two phases as in other methods, but uses the order of solidification in Al-Si alloys. How to make the Si foam, its characteristics including its density and strength, and purity of the extracted Si particles after acid leaching are reviewed.