Disclosed is a vanadium trap for use in FCC which comprises a major amount of calcined kaolin clay, free magnesium oxide and an in situ formed magnesium silicate cement binder. Also disclosed are procedures for the preparation of the trap by forming a slurry in water of hydrous kaolin clay, magnesium oxide or magnesium hydroxide and sodium silicate, aging the slurry to form magnesium silicate in situ, optionally adding additional kaolin, colloidal silica or both, spray drying, and calcining the resulting spray dried microspheres without forming appreciable amounts of crystalline magnesium silicates or crystalline magnesium aluminates.