宝珠覆膜砂旧砂再生工艺研究

Study on Regeneration Processing Technology of Used Pearl Coated Sand

对粒度为100~200目的宝珠覆膜砂旧砂进行热法再生试验研究,着重探讨了不同加热温度和保温时间对再生砂发气性及砂粒表面显微形貌的影响。结果表明:热法再生最优加热温度为700℃左右,保温时间为20 min。再生砂覆膜后抗拉强度和抗弯强度分别达到2.63 MPa和6.08 MPa。经热法再生后,宝珠覆膜砂旧砂表面树脂膜分子键遭到破坏,中间产物不断氧化产生气体释放,砂粒重新获得较高的表面能,其工艺性能基本接近同种新砂,具有良好的经济效益。

In this paper, the thermal regeneration experiment of 100-200 mesh used pearl coated sand was carried out. The effects of different heating temperatures and holding time on the gas evolution of reclaimed sand and the surface microstructure of sand were discussed emphatically. The results show that the optimum heating temperature for thermal regeneration is about 700℃ and the holding time is 20 min. The tensile strength and flexural strength of recycled pearl sand after coated reached 2.63 MPa and 6.08 MPa respectively. After thermal regeneration, the molecular bonds of the resin film on the surface of the used pearl coated sand are destroyed, the intermediate products are continuously oxidized and the gas is released, and the grit regains higher surface energy. Its process performance is basically close to the same kind of new sand, which has good economic benefits.