-Z-

Zircon The mineral zircon silicate, ZrSiO4, a very high melting point acid refractory material used as a molding material in steel foundries.

Zirconia ... ZrO2 an acid refractory up to 2500 C (4532 F) having good thermal shock resistance and low electrical resistivity.

Zirconium ... Silvery-white, metallic element, mp 1860 C (3380 F), a powerful deoxidizer when added to molten steel.