Efficiency in the Extraction of Pure Silicon from Al-Si Alloy Melts by a Combined Process of Solvent Refining and Centrifugation for Solar Silicon Feedstock

Abstract

Solvent refining of silicon from Al-Si melts assisted by a centrifugation was investigated for three alloys in the Al-Si system. Silicon was successfully separated from aluminum-rich phase in the form of a foam by centrifugation. As the silicon content increased, the recovery decreased because less aluminum-rich phases remained in the silicon foam. The weight ratio before and after acid leaching of the silicon foam was inversely related to its apparent density before acid leaching. The purity of the extracted silicon decreased slightly with increased silicon content. The purity of the silicon flakes obtained from the Al - 30% Si alloy was 4N, except aluminum. Boron and phosphorus in the silicon flakes could be lowered effectively by decreasing the silicon content in the Al-Si alloys

Separation of Pure Silicon from Al-Si Alloy Melts

“…9. Contents of boron and phosphorus in silicon flakes after acid leaching and segregation ratios [2] of boron and phosphorus in the silicon melt [7].…”

Laboratory assessment of isothermal separation of V containing spinel phase from vanadium slag by centrifugal casting

“…7 Furthermore, centrifugal technology has been successfully applied in the preparation of functionally gradient materials [8][9][10][11] and removing impurities from alloy melts. [12][13][14] Based on the above characteristics, it should be possible to separate V containing spinel phase that was precipitated early from vanadium slag by centrifugal casting. A schematic process route is shown in Fig.…”

“…For the third process of centrifugal separation of the V slag, the melt containing V containing spinel particles is charged into the rotating drum (9) through the feed pipe (7), where the enriched V containing spinel particles move to the inner wall of the rotating drum, while the gangue would pass through the holes of the rotating drum and be discharged through the overfall weir. When V containing spinel particles accumulate to a certain thickness (.10 mm) on the wall of the rotating drum, the scraper blade ( 8) is used to scrape off the particles to the slag notch (14) and so the V containing spinel material would be obtained.…”