| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide inorganic foaming particles for a lightweight filler obtained by utilizing waste fine sand (industrial waste) occurring in the process of producing molding sand, and in the process of treating the material for a mold, and to provide a production method therefor. SOLUTION: The inorganic foaming particles are obtained by subjecting a granulated matter containing (A) fine waste sand collected in the process of producing molding sand, or waste fine sand of at least one kind of granular body collected in the process of treating the material for a mold including the process of producing a mold material and a mold, the process of recovering sand grains from a used mold after casting, and the processes, e.g. of polishing, roasting and classifying the recovered sand, and (B) powdery expandable shale as essential components to burning and foaming, and have a specific gravity under oven-dry of 0.3 to 1.0. The method of producing the inorganic foaming particles contains a granulation process where a mixture of the waste fine sand in the (A) component, and the powdery expandable shale in the (B) component is granulated in the ratio of (A)/(B)=10/90 to 80/20 by mass ratio, and a burning process where the granulated matter obtained in the same process is foamed at 1,100 to 1,300 deg.C.</p> |
