- 學位論文
回收都市垃圾焚化飛灰燒製高價值陶瓷膜之研發
A Study on the High Value Ceramic Membrane Sintering by MSWI Fly Ash Recovery
摘要
都市垃圾焚化後產生之飛灰，目前多以水泥固化後掩埋為主，我國由於掩埋用地取之困難且即將面臨掩埋容積飽和之現象，循環再利用已成為未來的趨勢。本研究團隊曾利用廢玻璃、飛灰、高嶺土及坡縷石燒結出最高等級之調濕陶瓷材料，擬將此經驗進而應用於更高價值廢水MBR陶瓷濾膜之研究。 首先，以液固比5洗除飛灰中之溶解性鹽類，再以液固比5進行機械化學濕式研磨1小時來穩定重金屬。接著經由適當摻配廢玻璃、坡縷石與高嶺土後，加壓製作生坯，並以充入氮氣進行低氧燒結，研製成多孔性陶瓷濾膜；成品經由清水通量、過濾能力、健度、孔隙分析、SEM、TCLP、XRD及金屬固相殘留率等分析，以確保其品質、功能與二次污染預防。 研究結果顯示，以玻璃：研磨灰：高嶺土=60：20：20燒結900 ℃，持溫30分鐘，得到最佳之樣品，燒結三相圖最佳成分落在SiO2 30-40 %，Al2O3 10-20 %，CaO等60-70 %；增加玻璃可降低燒結溫度，60 %之玻璃，僅需900 ℃，30-40 %之玻璃則須1,000 ℃；最佳條件之樣品，其抗彎強度達12.19 MPa；燒結溫度與玻璃量的增加有助於健度之提升，最佳條件之健度為0.27 %，遠低於標準之18 %；毒性溶出程序(TCLP)重金屬普遍低於焚化底渣再利用標準之1/10，以最佳條件為例，總鉻溶出為0.28 mg/L；陶瓷濾膜之清水通量，在多種壓力測試下都有優於市售日本陶瓷濾膜在1 kgf/cm2下，通量40 m3/m2/d的表現，最佳條件在0.8 kgf/cm2下其通量為126 m3/m2/d；以生活污水之活性污泥進行過濾能力之評估，其出流水之懸浮固體皆趨近於0。
並列摘要
Most of the municipal solid waste incinerator (MSWI) fly ash are solidified followed by landfilling currently. However, due to the difficulty of burying land and the imminent shortage of burying capacity, resource recycling is becoming the future trend. The research team used to blend the pretreated fly ash with waste glass, kaolin and palygorskite to sinter the highest level of humidity-controlling ceramic successfully. In this study, a higher value MBR ceramic membrane development was explored on the base of the past experience. Firstly, the soluble salt in the fly ash was effectively washed out as liquid/solid ratio 5, followed by wet milling with liquid/solid ratio 5 for 1 hour, in order to stabilize the heavy metals; then blended with waste glass, palygorskite and kaolinite in different ratio to press in a mold, followed by sintered at different temperature and nitrogen injection to perform a low-oxygen atmosphere in order to control the heavy metal leaching. The porous ceramic membrane samples were analyzed by clear water flux, filtration ability, soundness, pore size analysis, SEM, TCLP, XRD and the metal residual, to ensure its quality, functionality and secondary pollution prevention. The results indicated that, the prescription of waste glass: milled ash: kaolin for 60: 20: 20, sintered at 900 ℃, holding 30 min, was the best condition. The proper range of 3-phase diagram of sintering for SiO2: Al2O3: CaO were 30-40 %, 10-20 % and 60-70 % relatively; when the percentage of glass was increased, the required sintering temperature was lower, only 900 °C for the sample of 60 % glass was added, while 1,000 °C were needed for 30-40% glass. At the best conditions, the bending strength was 12.19 MPa. The increasing of sintering temperature and glass composition, could improve the weathering resistance, at the best condition, the soundness was 0.27%, which was far below the standard of 18%; the TCLP of heavy metals were generally less than 1/10 of the standard for reuse of MSWI bottom ash, at the best condition, T-Cr was 0.28 mg/L. The results of clear water flux tests were better than the commercialized Japanese product under the pressure at 1 kgf/cm2 and the flux was 40 m3/m2/d. The best condition was 126 m3/m2/d at the pressure 0.8 kgf/cm2. The filtration ability for the activated sludge of sewage treatment system, SS of the filtrate were all close to 0.