| Summary: | 碩士 === 國立臺北科技大學 === 資源工程研究所 === 99 === In silicon wafer manufacturing, a large amount of slurry waste is produced and feedstock is wasted during cutting process, resulting in environmental pollution and high cost. Recycling glycol solution is regarded as an important method to reduce the waste and cost. This study recovered glycol solution from the silicon slurry waste according to feasible industrial recycling technologies. The recovered glycol could be reuse in cutting process. We used gravity settling or centrifugation to separate liquid from the waste. The experimental results show that increasing temperature or A-solvent content of the waste can accelerate the separation by settling or centrifugation and produce a clear liquid layer. Its recovery yield reached 61% by gravity settling and 97% by centrifugation. However, adding other solvents could not produce clear glycol solution. The parameters of centrifugation were also studied, and it was found 5500 rpm for 8 hr-centrifugation or 3 times 1 hr-centrifugation resulted in good separation performance.
The collected liquid after settling or centrifugation should be purified to reuse in cutting process. This study reports the solubility of our glycol in the solvent A would decrease by increasing temperature. Therefore, heating the glycol-A solution would purify the glycol without the equipments for vacuum or the formation of vapor. Finally, the recovered glycol solution was examined and compared with the original one. The examination results show our recovered glycol solution are the same as the original one, and may be reuse to silicon cutting process.
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