| 摘要 |
PURPOSE:To prevent putrefaction and to improve working environment by dispersing a binder, anti-setting agent and refractory aggregate into water to prepare a slurry then spraying and drying the slurry by a spray dryer thereby forming the perforated hollow powdery and granular material. CONSTITUTION:A carbon material such as graphite or coal powder or metallic oxide such as alumina or silica and the mixture composed thereof are used as the refractory aggregate. Clay, dextrin, etc. are used for the binder and bentonite, methyl cellulose, etc. are used for the anti-settling agent. The compounding ratios of the components consist of 80-99wt% refractory aggregate, 0.5-1.0% binder and 0.5-10% anti-settling agent. The mixture is mixed with water at a ratio of 1pt.wt. solid component with 0.5-2.5pts.wt. water to prepare the slurry. The slurry is sprayed and dried by the spray dryer and the mold coating material consisting of the perforated hollow powdery and granular material is obtd. Since the moisture content is low, the putrefaction during storage is prevented and since the generation of powder dust is obviated, the working environment is improved. |
