锆英砂及其放射性问题锆英砂是优良的耐火材料,它的主要成分是硅酸锆(ZrSiO_4),与当前铸造生产中常用的其他造型材料相比,具有下列优点: 1.熔点高,约为2400℃; 2.几乎完全不被熔融金属所润湿; 3.加热时无相变,热膨胀极小; 4.导热率高,约为硅砂的4倍。铸造生产中用锆英砂作造型材料,大约起始于本世纪40年代。最初是用 Zircon sand and its radioactive problems Zircon sand is an excellent refractory material whose main component is zirconium silicate (ZrSiO 4), which has the following advantages compared with other modeling materials commonly used in foundry production: 1. High melting point, About 2400 ℃; 2. Almost no wetting by the molten metal; 3. No phase change during heating, thermal expansion is minimal; 4. High thermal conductivity, about 4 times the silica sand. Casting production with zircon sand molding material, began about 40 years of this century. First used