| 摘要 |
PURPOSE:Foaming paticles of natural glass is heated at a specific temperature- rising rate to increase their foaming performance, thus producing foamed particles being suitable for the use as an insulating material or light-weight aggregation. CONSTITUTION:Foaming particles of natural glass such as obsidian or SIRASU (a pile of volcanic ash and bombs) are foamed by heting wherein the temperature is raised at a rate of 10-50 deg.C/min. Generally, it is known that these natural glasses foame and swell, when they are heated at 800-1,300 deg.C and conventionally, they have been charged into an atmosphere heated to 800-1,300 deg.C. But, the foaming has been unsatisfactory. The presence pocess is distiguished by higher foaming rate than any conventional ones and gives almost spherical foamed particles. For example, the foaming rate can be increased by more than 50%. |
