| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a safety aggregate having strength from inorganic waste, and to effectively use burned ash of general waste to the safety alternative of sand. SOLUTION: This alternative is sand like granules using, as the prime raw materials, burned ash of general waste, sewage sludge and industrial waste, in which harmful dioxins is decomposed or incorporated as harmless minerals, or manifesting lowered content of harmful substance such a cadmium, lead, hexavalent chromium. This alternative is produced by adding water to the raw material to adjust the water content of them, adding polymer containing carboxyl group if required, granulating into sand shape. After granulation, calcium oxide is added to strengthen the granules by carrying out a reaction with water in the granules. Preferably, the process contains adjusting step of the raw material, in a case using burned ash of general waste, they are burned again at 950-1200 deg.C and granulated, and in case using burned ash of sewage sludge, they are burned again at above 800 deg.C. The free calcium content is adjusted to below 5%, by adding limestone if required, before burning again.</p> |
