Abstract: The invention relates to a refractory thermally-insulating component consisting essentially of refractory ceramic fibers which are mechanically combined with one another, the composition of which comprises at least 97.5% by weight of alumina, silica and zirconia in total, wherein:a) no organic or inorganic binder binds the fibers to one another;b) the fibers have the following chemical composition, as % by weight:Al.sub.2 O.sub.3 : 33-45%SiO.sub.2 : 41-53%ZrO.sub.2 : 5.5-17%MgO: 0.02-2%other oxides:<0.50% with Fe.sub.2 O.sub.3 +TiO.sub.2 .ltoreq.0.20% and Na.sub.2 O+CaO+K.sub.2 O.ltoreq.0.30%;c) the said fibers homogeneously have, throughout the entire body of the component, a degree of crystallinity of not less than 30% and not more than 64%, the crystals present being essentially formed of mullite crystals and of quadratic zirconia; andd) the said component has a linear shrinkage of no more than 3% after being held for 24 hours at 1450.degree. C.

Abstract: Reactive derivatives of zirconium, are provided which are in the form of a pulverulent white, non-crystallized solid which is dry in appearance, and consist of metazironic acid, ZrO (OH).sub.2, accompanied by free or weakly bound water, some of the OH.sup.- ions being optionally replaced by halide ions. The ZrO.sub.2 content of these derivatives is from 60 to 92% by weight inclusive, the water content ranges from 3 to 40%, and the halide ion content can range up to approximately 5% by weight. The solid derivatives of the invention can be easily converted into usual reactive derivatives of zirconium by reaction with an aqueous solution of an acid.

Abstract: A process for the preparation of improved zirconium oxides comprising A) providing a zirconium oxide which has been produced by thermal decomposition of zircon followed by chemical digestion of the resultant silicate phases, B) reacting the zirconium oxide at high temperature with an alkali metal hydroxide or carbonate so as to form an alkali metal zirconate, C) hydrolyzing the resultant alkali metal zirconate so as to produce a suspension of zirconium oxide hydrate in a concentrated solution of alkali metal hydroxide, D) separating the zirconium oxide hydrate from the concentrated solution and washing the zirconium oxide hydrate which has been isolated, and E) drying the zirconium oxide hydrate at a temperature in the range of from 110.degree. to 570.degree. C.

Abstract: A feeder trough for transferring molten glass from a glass furnace to an object-forming station, the feeder trough comprising a channel at one of its ends to the furnace and at its other end to a bowl having at least one feeder orifice a sill which has, on its downstream face, a substantially vertical wall, occupies the entire width of the channel and has a thickness of approximately 4 to 10 cm and a height such that it allows a stream of glass approximately 8 to 10 cm thick to pass over it; and a heatable bottom drain provided upstream of the sill and practically adjoining the latter.

Abstract: The invention relates to the regenerators of glass melting furnaces. It relates more particularly to a ceramic element for equipping regenerators of glass melting furnaces, having at least one vertical wall, the mean thickness of which is at the most 40 mm, characterized by the presence, on at least one face of this vertical wall, of a plurality of obstacles forming an integral part of the element, the protrusion of the obstacles relative to the base surface of the wall being at least 5 mm, the ratio of the distance separating two consecutive obstacles in the vertical direction to the said protrusion being comprised between 3 and 15, and the angle x formed by the obstacle with the base surface of the wall in the given direction of movement of the fumes and the angle y formed by the obstacle with the base surface of the wall in the given direction of movement of the air to be heated being such that x is less than or equal to y. Application in the glass industry.

Abstract: A process for the preparation of zirconia hydrate from zirconia by reaction of the latter with solid sodium hydroxide at 550.degree.-1,400.degree. C. to form Na zirconate; hydrolysis of the latter to form a suspension of zirconia hydrate in aqueous sodium hydroxide; separation of most of the aqueous sodium hydroxide; treatment of the zirconia hydrate containing residual aqueous sodium hydroxide with an ammonium salt; and separation, washing and dewatering of the purified zirconia hydrate obtained.The zirconia hydrate can be used for the preparation of zirconium compounds.

Abstract: The invention relates to the chemistry of zirconium.It relates particularly to a reactive zirconium oxide in the form of fine particles whose median diameter does not exceed 10 .mu.m, which has a structure chosen from the amorphous structure and the structure crystallized in the tetragonal form, the size of the elementary coherence regions in the latter case being between 10 and 30 nm, and which has a B.E.T. surface area of at least 30 m.sup.2 /g, and to a process for its preparation.Use in the field of ceramic materials.

Abstract: A process for the assembly of at least one adjacent pair of component structural elements to form an upright vault structure, each of the elements having a recess, wherein the elements are arranged flat on the ground in the desired relative configuration and are temporarily joined together into an assembled unit by an assembly device, whereafter the device and the assembled unit are lifted and placed in a final position of the structure, and the joining device is removed from the elements. The joining device includes a post and a pair of opposed spaced jaw members mounted on the post for relative movement toward and away from one another, a pair of wing members being afixed to one of the jaw members, the wing members extending from opposite sides of this jaw member and toward the other of the jaw members and respectively engaging the recess of the structural elements. The jaw members are clamped together about the joined structural element.

Abstract: A transverse-burner recuperative furnace for glass making, which comprises burner blocks of which the inner aperture, of generally elongate rectangular shape, exhibits a first portion of constant cross-section extending from the rear face of the burner block, and a second portion progressively flaring upwards and downwards to the front face of the burner block, such second portion exhibiting an angle of flare .alpha. of not more than 15.degree., and the cumulated total length of these apertures representing at least 0.65 times the distance between the extreme burner blocks.

Abstract: The present invention is directed to a regenerator furnace which is useful in making glass, the regenerator furnace including burner pipes, each burner pipe having a generally square or rectangular cross section, the upper part or cover of each pipe being built with monolithic elements made of refractory material and of sufficient extent for each upper element to rest at its ends on the refractory elements forming port side walls, these lateral elements themselves resting on refractory elements forming the base of the pipes.

Abstract: The invention relates to beads used for crushing or dispersion which are formed by fusion, conversion into beads and solidification of an appropriate batch consisting essentially, on the oxide basis, of up to 85% by weight of ZrO.sub.2, a proportion of SiO.sub.2 such that the weight ratio ZrO.sub.2 /SiO.sub.2 is greater than or equal to 1.5, an optional proportion of Al.sub.2 O.sub.3 such that the weight ratio Al.sub.2 O.sub.3 /SiO.sub.2 is 0 to 1.5 and an optional proportion of Na.sub.2 O such that the weight ratio Na.sub.2 O/SiO.sub.2 is from 0 to 0.04, the batch also containing at least one of the additional oxides of MgO and CaO in proportions such that the weight ratio MgO/SiO.sub.2 is from 0.03 to 1 and the ratio CaO/SiO.sub.2 is from 0.03 to 1.45.