| 摘要 |
PROBLEM TO BE SOLVED: To obtain the ceramic foam having both a low specific gravity and a high strength and capable of being used as an artificial soil, a concrete aggregate, etc., by compounding coal ash, a powdery material containing a magnesium compound in a specific amount and a power material having plasticity so as to give a final product composition having a specific component ratio, granulating the composition into granules having a diameter in a specific range, and subsequently calcining the granules in a specified temperature range. SOLUTION: The powdery material containing the magnesium compound is preferably a powdery material containing a magnesium compound of >=5 wt.% converted into magnesium oxide. The components are compounded so as to give a final product composition comprising 3-10 wt.% of MgO, 2-16 wt.% of Fe2 O3 , 10-25 wt.% of Al2 O3 and 50-80 wt.% of SiO2 as the converted oxides, respectively. The produced granules have a diameter in a range of 0.1-10 mm. The calcination is carried out at 1,100-1,300 deg.C. In the calcination process, a fluid medium and a fluidized bed calcination oven are preferably used.α-alumina is used as the fluid medium.
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