| 摘要 |
<p>Prodn. of expanded materials by heating at 800-1200 degrees c a mixture of (a) ground, natural silicate material, rock etc., with (b) a fusing aid and a blowing agent, according to the Parent Patent is improved by using as component (a) a low-melting, water - contg., ground volcanic rock, or a similar silicate-contg. waste stone material or ash (basalt, tuff, pumice silicate wastes from metallurgical processes, ashes, etc.,) and as component (b) a substance (s) accelerating the sintering of (a) in such a manner that the evapg. water of crystallisation or other gases are trapped in small voids which are rapidly sealed. As a result, a great number of very small, sealed cells are formed (>10000 per cm3), whereby a product of very high compressive strength is obtained.</p> |
