| 摘要 |
PURPOSE:To improve the heat insulatability of molten metal and to prevent the oxidation thereof by using a granular material which consists of a porous seed in the central part and is formed a dense shell in the outside circumferential part and has a prescribed grain size to constitute a heat resistant inorg. material having specified bulk specific gravity. CONSTITUTION:The heat insulating material for molten metal is constituted of the heat resistant inorg. material and is made of the granular material having <=0.5 bulk specific gravity and 3-30mm. grain size. The spherical body is formed by mixing uniformly the heat resistant inorg. material of the granular material consisting of the porous material in the central part, hollow type heat resistant inorg. material and silicic acid into an alkali, kneading the mixture with a high-polymer resin, etc. mixed with a solvent. Such porous seed 1 is dipped into the aq. soln. of an Mg salt to stick the solid Mg salt to the porous inside part. The material 1 is then put into the alkali liquid mixture composed of the heat resistant inorg. material and silicic acid to form the film 2 of the shell in the outside circumferential part. The heat insulating material of the granular material formed by such method has no carburization and contributes to the improvement in the heat insulatability of the molten metal and the prevention of the oxidation thereof. |
