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Silicon sawing waste treatment by electrophoresis and gravitational settling

2011; Elsevier BV; Volume: 189; Issue: 1-2 Linguagem: Inglês

10.1016/j.jhazmat.2011.02.070

1873-3336

Tzu-Hsuan Tsai,

Microbial Fuel Cells and Bioremediation

In silicon wafer manufacturing for solar cells, a great amount of hazardous sawing waste with tiny Si particles is produced, resulting in serious environmental problems. Recycling Si and abrasives from the waste is regarded as an effective solution. Based on the view of recycling, Al2O3 might be good abrasives for cutting Si ingot due to its larger density and higher isoelectric point than SiC. This study reports the separation of Si/SiC and Si/Al2O3 mixtures by electrophoresis and gravitational settling. At pH 9, nearly uncharged Al2O3 settled quickly and the negatively charged Si moved toward the anode, leading to an obvious Si distribution on the cell bottom. The experimental results show the separation performance of Si and Al2O3 at pH 9 was better than at pH 2.5, and the performance was higher than that between Si and SiC. The minimum and maximum Al2O3 contents remaining in Si/Al2O3 mixture were 9 wt% and 90 wt% after applying 1 V/cm for 24 h at pH 9. The recovered material with high Si content can be considered as a new Si source for solar cell, and the abrasives can be reused in the sawing process.