Glass-ceramic from sewage sludge ash

Glass-ceramic was produced by adding limestone to sewage sludge incinerated ash. Black glass was produced by melting a blended ash batch at 1450 degrees C. For nucleation, this glass was reheated at 800 degrees C for 1 h, and reheated at 1100 degrees C for 2 h to form glass-ceramic. The main components of sewage sludge incinerated ash are SiO2 and Al2O3. Because small amounts of Fe2O3, sulfur and carbon are included, the addition of limestone alone can generate the crystal nucleant, FeS, to form anorthite (CaO . Al2O3 . 2SiO(2)) crystal. The glass-ceramic showed superior characteristics of high strength and acid resistance for use in construction materials.