| 摘要 |
<p>Plastic material or moldable product, for casting, comprises 1-10% of binder based on alkali silicate, an additive containing 1-10 wt.% of amorphous silicon dioxide, and quartz sand residue with a grain size of 0.01-5 mm; where the amorphous silicon dioxide exists as spherical shape, up to 1.5 wt.% of the particle exhibits a diameter of >= 45 mu m, and on the surface of the amorphous silicon dioxide a source phase is formed with a thickness of 0.5-1% related to the average grain diameter. An independent claim is included for the preparation of the plastic material or moldable product comprising reacting the additive such as amorphous, dissolved, spherical silicon dioxide with a particle having a grain size of greater than 45 mu m in a suspension with a solid material having 20-70% of silicon dioxide; adjusting the pH to 9-14; alkali treating the amorphous silicon dioxide for at least 4 minutes, until a source phase is formed on the silicon dioxide surface; homogeneous mixing of silicon dioxide with the molding sand and binder, where the mixing ratio of the binder/silicon dioxide to form a sand is 1-10 to 90; and inserting the silicon dioxide with the molding sand and the binder into a molding box, under pressure and drying to a finished core.</p> |
