Abstract: A prefabricated part made of vitreous fused silica for use as a refractory, and in particular, for use in repairing coke ovens, which contains over 90% by weight of SiO.sub.2. The prefabricated part includes about 20 to 50% by weight of vitreous fused silica having 1 to 6 mm grain size, 20 to 40% by weight of vitreous fused silica having 0.1 to 1 mm grain size, 15 to 35% by weight of finely ground vitreous fused silica having grains less than 0.1 mm in size, 1 to 10% of finely ground vitreous fused silica having a specific surface area according to BET larger than 20 m.sup.2 per gram, 1 to 10% by weight of cement and 0.1 to 8% by weight of a phosphorous compound.

Abstract: A process for producing a composite material including at least two layers, of which at least one layer (1) is composed of ceramic material, by moistening the raw materials and aggregates for the layer (1) of ceramic material, mixing them and pressing them to form a green layer. Weak contact surfaces are formed on the green layer and the layers are pressed together to form a composite material. This is followed by drying and firing the composite material. The green layer is compacted by rollers to form the weak contact surfaces. The layers are pressed together to form the composite material by a further rolling operation.

Abstract: A zirconium silicate brick and a method for producing same, the brick having a starting powder used to form the brick, the starting powder having minimal amounts of contaminants in the amount of not more than about 0.3 percent Al.sub.2 O.sub.3, not more than about 0.2 percent TiO.sub.2, and not more than about 0.1 percent Fe.sub.2 O.sub.3, each, based on the weight of the starting powder, to which a phosphorous compound in the amount of about 0.1 percent to about 5 percent based on the weight of the starting powder is added prior to making the brick for producing a brick with improved corrosion resistance for use in glass melting facilities with boron silicate glasses, and having improved decomposition behavior at higher glass melting temperatures.