| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a technique capable of taking measures against hexavalent chromium, while reducing the production cost of foam glass. Ž<P>SOLUTION: In illustration (a), a lidless container 35 with the top open is filled with a crushed powder 30. The crushed powder 30 comprises glass particles 21, carbon fine particles 31 and a chromium-based substance 36. As shown in (b), the crushed powder 30 is heated at about 800°C from above the lidless container 35, so that the glass particles in an upper surface melt and form a glass layer 37. Thereafter, the space under the glass layer 37 becomes a reducing atmosphere, and since oxidation does not proceed, there is no fear of generation of hexavalent chromium. As shown in (c), the crushed powder 30 is then wholly subjected to concluding firing at about 800°C from the peripheries of the lidless container 35. Foam glass 40 obtained after cooling contains a large number of bubbles 42 in glass 41 as shown in (d). Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž
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