title: Recovering low-turbidity cutting liquid from silicon slurry waste.
abstract: In order to recover a low-turbidity polyalkylene glycol (PAG) liquid from silicon slurry waste by sedimentation, temperatures were adjusted, and acetone, ethanol or water was used as a diluent. The experimental results show that the particles in the waste would aggregate and settle readily by using water as a diluent. This is because particle surfaces had lower surface potential value and weaker steric stabilization in PAG-water than in PAG-ethanol or PAG-acetone solutions. Therefore, water is the suggested diluent for recovering a low-turbidity PAG (<100 NTU) by sedimentation. After 50 wt.% water-assisted sedimentation for 21 days, the solid content of the upper liquid reduced to 0.122 g/L, and the turbidity decreased to 44 NTU. The obtained upper liquid was then vacuum-distillated to remove water. The final recovered PAG with 0.37 NTU had similar viscosity and density to the unused PAG and could be reused in the cutting process.
authors.affiliation: Department of Materials and Mineral Resources Engineering, National Taipei University of Technology, Taipei 10608, Taiwan. Electronic address: tzhtsai@ntut.edu.tw.
authors.forename: Tzu-Hsuan
authors.initials: TH
authors.lastname: Tsai
authors.affiliation: Department of Materials and Mineral Resources Engineering, National Taipei University of Technology, Taipei 10608, Taiwan.
authors.forename: Yu-Pei
authors.initials: YP
authors.lastname: Shih
mesh_terms: D000096:Acetone / Q000737:chemistry; D000431:Ethanol / Q000737:chemistry; D006018:Glycols / Q000737:chemistry*; D007220:Industrial Waste; D009391:Nephelometry and Turbidimetry; D011108:Polymers / Q000737:chemistry*; D059027:Recycling / Q000379:methods*; D012825:Silicon; D014867:Water / Q000737:chemistry
chemical_list: D006018:Glycols; D007220:Industrial Waste; D011108:Polymers; D014867:Water; D000096:Acetone; D000431:Ethanol; D012825:Silicon
keywords: Cutting liquid; Recovery; Sedimentation; Silicon slurry waste; Turbidity