| 摘要 |
<p>PROBLEM TO BE SOLVED: To obtain a material having small dry specific gravity by compounding incineration ash of sewage sludge and coal ash to prepare the source material, granulating the source material and then calcining. SOLUTION: Water is added to the source material prepared by preferably compounding 40 to 185 pts.wt. of coal ash to 100 pts.wt. of incineration ash of sewage sludge, and the obtd. mixture is granulated and calcined. The amt. of water added is controlled to obtain 15 to 35 wt.% of the water content in the source material during granulation. As for a granulating method, an extruding molding machine, pan-type pelletizer or the like is used. A rotary kiln, grate type furnace or fluidized bed furnace method, or the like is used to calcine the granulated material. The calcination temp. is preferably 1,000 to 1,150 deg.C. The compsn. of the incineration ash of sewage sludge consists of 20 to 80 wt.% of SiO2, 5 to 30 wt.% of Al2O3 and 2 to 20 wt.% of Fe2O3. The compsn. of the coal ash consists of 50 to 75 wt.% of SiO2, 15 to 30 wt.% of Al2O3 and 0.5 to 10 wt.% of Fe2O3. A binder (e.g. bentonite) is preferably added by 1 to 5 wt.% to the compounded source material.</p> |
