| 摘要 |
PURPOSE:To obtain lightweight granules having low water absorption and improved strength, by coating the surface of core material of granule of perlite raw ore with glass powder through a binder and heating the coated material so that the core material is expanded and sintered to the glass powder layer. CONSTITUTION:Perlite raw ore is ground to form granules, the granules are used as a core material, a binder is stuck to the surface of the core material and the surface is coated with glass powder which contains optionally a blowing agent. Then, the granulated material is dried, heat-treated, the granule of perlite raw ore which becomes the core material is expanded in the final process, so that the glass powder layer is sintered to the core material. Consequently glass coated shell granule which makes the most of characteristics of non-combustible particle of perlite which becomes the core material, having suppressed water absorption and bulk density and extremely improved crushing strength is easily obtained.
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