LAUSR

Abstract During wire sawing of silicon ingot into wafers, 40% of silicon is lost and being combined to cutting fluid to form the kerf slurry waste. Recycling this slurry containing silica materials represents an economical method to manage this waste. A study on recycling SiC and its use for the preparation of sodium silicates (Na2SiO3) precursor to synthesize silica gel was conducted. The recycling process included a liquid-liquid extraction and alkali dissolution that were optimized to generate a mixture of powder containing 28% Si and 72% SiC. The alkali dissolution process was carried out by sodium hydroxide in optimal conditions of the mass ratio (NaOH/Slurry), temperature, and reaction duration. NaOH reacted with silicon in the slurry waste to prepare the Na2SiO3 precursor for the synthesis of silica xerogel by employing a Sol-Gel method. X-ray diffraction (XRD), Scanning Electron Microscopy coupled with Energy Dispersive Spectrometric Analysis (SEM-EDS), and optical microscopy were used to characterize the structure, composition, and morphology of the powder. In our study, a SiC with 99.4% purity was obtained and the gels formed are irreversible and present a syneresis which leads to a consolidated solid.