工廠進行資源化廢觸媒時常伴隨產生含硫飛灰廢棄物,原先的掩埋處理除了對環境造成不小的負擔外,同時也必須多負擔一筆掩埋費用。本研究以再結晶技術為核心,進行資源化含硫飛灰廢棄物。文中先探討不同的再結晶降溫速率,對所獲得十水合硫酸鈉的時間、純度及產率之影響;接著再以第一次結晶產物進行第二次再結晶。研究結果顯示:第一次再結晶時所使用的兩種降溫策略,皆可獲得純度高達90%以上結晶物,產率約30%~40%;再進行第二次再結晶時,兩種降溫策略之結晶物也都可於1小時內析出,其中快速結晶策略可獲得純度高達99%以上,產率約60%的結晶產物。再結晶後的廢液以碘滴定法分析出其亞硫酸鈉含量,數據顯示廢液中之亞硫酸鈉比例高達70%以上,有再資源化價值,後續將繼續進行資源化亞硫酸鈉研究,達成工廠零廢棄物的目標。
This study intends to develop a recrystallization technology that can reclaim the waste ashes.We used two recrystallization processes to reclaim the waste ashes. We conducted first recrystallization experiments to investigate the effect of rate of descending temperature on the purity, yield and time of recrystallization. The crystallization products from the first crystallization were subjected to the second recrystallization. Experimental results showed that the rate of descending temperature adopted in our experiments achieved a high purity sodium sulfate (Na2SO4) above 90% and yields of 30%~40%. The second crystallization brought the purity and yield of the sodium sulfate above 99% and 60%, respectively.The waste solutions of the recrystallization processes were analyzed by iodine titration method. Experimental results showed that the concentration of sodium sulfite (Na2SO3) in the waste solutions was above 70%. The waste solutions of the recrystallization processes are good candidates for recycling the sodium sulfite.