ABSTRACTThis is a record of the results of five years' research on refractory uses for a chemically purified grade of zircon and electrically fused zirconia of high purity. The products investigated included semi‐permanent foundry molds, refractory brick and cements, ladle nozzles, and crucibles. Electric firing and a small oil‐fired tunnel kiln are described. Sintered zircon grog was found superior to electrically fused grog. Zircon brick made with 50% grog, using 20% milled zircon for the permanent bond and fired at 1600OC for an hour, showed no firing shrinkage, very slight volume change, and high compressive strength at 1600°C. They were extremely resistant to spalling but did not resist basic slags or metallic oxides very well at high temperature. Zircon‐bonded magnesite brick were more refractory than ordinary magnesite, more resistant to spalling, and had about the same slag resistance as magnesite. Zirconia was more refractory than zircon and had better slag resistance. Lime‐bonded zirconia crucibles of good spalling resistance were made, but the cost was higher than that o