Abstract: Dense zircon refractories having improved thermal shock damage resistance for use in glass melt or high alkali vapor contact applications comprise, and, consist essentially of, about fifty percent by weight or more ZrSiO.sub.4, at least about one percent zirconia in particle form distributed substantially uniformly throughout the composition of the refractory, and optionally, a zircon grain growth enhancing composition, preferably TiO.sub.2.

Abstract: Refractory compositions comprising at least eighty percent or more by weight Cr.sub.2 O.sub.3 densified by the addition of at least one-half percent and preferably about four percent TiO.sub.2 have about one-quarter percent to about fifteen percent by weight relatively finely divided monoclinic zirconia particles substantially uniformly dispersed therethrough to induce microcracks in the densified chromic oxide and improve thermal shock damage resistance of the refractory. Zirconia additions of up to at least five percent by weight exhibit the high glass corrosion resistance of similar densified chromic oxide compositions without zirconia.

Abstract: Fused AZS grain refractory compositions suitable for making ceramically or chemically bonded refractory articles, and the articles so made, are disclosed. The refractory compositions consist essentially of (a) 40-85 wt. % fused AZS grain, and (b) 15-50 wt. % of at least one constituent selected from the group consisting of (i) 10-20 wt. % reactive alumina and (ii) 0-45 wt. % chromic oxide.

Abstract: A refractory composition is disclosed which possesses low porosity, high density, exceptional strength and high abrasion resistance and is useful for lining fluid catalytic converter units, e.g., catalyst transfer lines, riser lines, J-bends, cyclones and all other areas where hot abrasion resistance and low thermal conductivity are desired. The composition consists essentially of by weight: (a) 44 to 89% of an abrasion-resistant refractory grain; (b) 10 to 50% of a hydraulically setting cement; (c) 1 to 6% of a filler consisting of very fine, substantially spherical particles of a metal oxide selected from the group consisting of Al.sub.2 O.sub.3, Cr.sub.2 O.sub.3, ZrO.sub.2, TiO.sub.2, clay minerals, carbon and fume SiO.sub.2 ; and (d) 0.01 to 1%, based on the total weight of the constituents (a), (b) and (c), of additives selected from deflocculants and wetting agents.

Abstract: A novel method of making a refractory material is disclosed comprising the steps of providing an electrical arc metal furnace, charging that furnace with a charge of refractory oxide, and selecting voltage, amperage and electrode spacings to create novel "hum and scum" melt conditions. This hum and scum condition is maintained until said charge is substantially melted. The described technique is particularly useful for melting magnesia chrome materials to produce fusion cast refractory products which are highly reduced and quite dense. The elaboration of this product requires higher energy input per pound concurrent with an increased consumption of reducing materials compared with standard preparation conditions. The resulting product exhibits higher oxidation weight gains, higher densities, lower porosities, high cold crush strengths, more thermal shock resistance, and better corrosion-erosion resistance than similar magnesia chrome refractory products fused using prior "arc and bark" processes.