宝珠砂是将煅烧过的铝矾土融化后喷吹造粒而获得的珠状的、耐高温的、低热膨胀率的人造陶瓷颗粒。由于宝珠砂的性价比优于铬矿砂和锆英砂，因此为铸造厂家提高铸件质量，降低生产成本和减少环境污染提供了简便且极为有效的方法。宝珠砂是目前全世界公认的最理想的新型铸造用砂，具有非常广阔的发展前景。
Ceramsite is the custom ceramicparticles with a spherical shape, high refractoriness and low thermal expansionbeing made by spraying the melted calcined bauxite. It provides a very simple butefficient way for the foundry-men to improving the quality of the castings,reducing the production cost and avoiding environmentalpollution, because of that it has the higher price ratio comparing with Chromite sandand Zircon sand. At thepresent, Ceramsite is acknowledged in the worldwide as the newest and the best idealsand for the foundries and has a very wide feasibility of applications for the futuredevelopment.
宝珠砂铸造陶粒具有下列优点：
1.热膨胀率低：热膨胀率低于其它铸造用砂。所以生产铸件的尺寸精度高，裂纹及缺陷少，铸件成品率高。
2.致密的球状粒形：粒形为球状，表面光滑且表面积小，流动性及填充性极好。因此在获得良好的铸模强度和高透气性的同时与其它型砂相比能够大量减少粘结剂使用量。同时还具有极好的溃散性。
3.耐火度高：主要成分是三氧化二铝，PH值呈中性，属铝硅系耐火材料，耐火性能很好，能满足各种金属及合金铸造要求。
4.耐破碎性好：宝珠砂的体积致密，强度高，重复再生使用也很少破碎，大幅提高型砂再生回用率，减少了废砂排放量，利于环境保护。
Ⅱ.CERAMSITE advantages are as follows
Solid sphere: The shape of Ceramsite is spherical with smooth surface and less surface area and offering a very good flowability and filling ability. To compare with other sands else, less binder is used at the same mold strength and higher venting ability. It also offers the excellent collapsibility.
Lower thermal expansion rate: It makes the dimensions of castings better, less crack and defect and higher output.
Lower breakage rate: Ceramsite has a higher density and a very lower breakage rate at the reclaimation. It makes a better reclaimation rate to reduce the waste sand to be favor to the environment.
High refractoriness: The major chemistry is Al2O3. PH appears neutral. It belongs to the refractoriness of the series of Aluminum and Silicon which has a very good refractory performance. It is suitable for all kinds of metal and alloy castings.
