Zirconium(IV) silicate

Zirconium silicate, also zirconium orthosilicate, ZrSiO4, is a chemical compound, a silicate of zirconium. It occurs in nature as zircon, a silicate mineral. Powdered zirconium silicate is also known as zircon flour.
Zirconium silicate is usually colorless, but impurities induce various colorations. It is insoluble in water, acids, alkali and aqua regia. Hardness is 7.5 on the Mohs scale.
Production.
Zirconium silicate occurs in nature as mineral zircon. Ore is mined from natural deposits and concentrated by various techniques. It is separated from sand by electrostatic and electromagnetic methods.
It can also be synthesized by fusion of SiO2 and ZrO2 in an arc furnace, or by reacting a zirconium salt with sodium silicate in an aqueous solution.
Uses.
Zirconium silicate is used for manufacturing refractory materials for applications where resistance to corrosion by alkali materials is required. It is also used in production of some ceramics, enamels, and ceramic glazes. In enamels and glazes it serves as an opacifier. It can be also present in some cements. Another use of zirconium silicate is as beads for milling and grinding. Thin films of zirconium silicate and hafnium silicate produced by chemical vapor deposition, most often MOCVD, can be used as a high-k dielectric as a replacement for silicon dioxide in semiconductors.
Zirconium silicates have also been studied for potential use in medical applications. For example, ZS-9 is a zirconium silicate that was designed specifically to trap potassium ions over other ions throughout the gastrointestinal tract. It is undergoing clinical trials for the treatment of hyperkalemia.
Zirconium disilicate is used in some dental crowns because of its hardness and because it is chemically nonreactive.
Toxicity.
Zirconium silicate is an abrasive irritant for skin and eyes. Chronic exposure to dust can cause pulmonary granulomas, skin inflammation, and skin granuloma. However, there are no known adverse effects for normal, incidental ingestion.