Abstract: A crystallized glass article formed of discrete small bodies of crystallizable glass fusion-bonded together at their interfaces is characterized in that a first layer extending from the article surface to a predetermined depth is non-porous, a predetermined thickness of second layer connected to and beneath the first layer being porous. Each of the small bodies in the first layer has needle-like .beta.-wollastonite crystals extending from the surface of the body to the interior thereof in a direction perpendicular to the surface of the body. Accordingly the article is characterized by a surface pattern defined by small bodies due to the differences of orientation of needle-like .beta.-wollastonite crystals and by a reduced specific gravity.

Abstract: A continuous process for the manufacture of cellular ceramic product. Ceramic feed material is transported successively through a preheat kiln section, through a foaming section whereat foaming agent mixed with the ceramic feed material is activated, and into a drawing kiln section. An elongate hollow product can be formed by drawing the foamed ceramic while soft around and past a hollow mandrel to form an elongate hollow cylindrical member.

Abstract: Foam glass developed under vacuum is continuously formed into a slab while being cladded on its major sides and longitudinal edges with sheet metal. The metal claddings or facings for the two major sides of the slab are held under tension during the solidifying of the slab body. End plates are inserted transversely through the product at specified points during its movement and sections of the continuous product are cut to length, whereby the sections are prestressed partly as a result of compression along two axes caused by differing coefficients of expansion of the cladding and foam glass body and partly to atmospheric compression of the product on a third axis perpendicular to its major sides. Modified forms of the product eliminate the metal cladding or skin entirely or provide the same as a cast-on coating without mechanical prestressing.

Abstract: A method and apparatus for making uniform pellets for laser driven fusion reactors which comprises selection of a quantity of glass frit which has been accurately classified as to size within a few micrometers and contains an occluded material, such as urea, which gasifies and expands when heated. The sized particles are introduced into an apparatus which includes a heated vertical tube with temperatures ranging from 800.degree. C to 1300.degree. C. The particles are heated during the drop through the tube to molten condition wherein the occluded material gasifies to form hollow microspheres which stabilize in shape and plunge into a collecting liquid at the bottom of the tube. The apparatus includes the vertical heat resistant tube, heaters for the various zones of the tube and means for introducing the frit and collecting the formed microspheres.

Abstract: Glassware having small bubbles or blisters that impart a handcrafted appearance to it is made by metering specially formed decomposable granules into a soda-lime glass melt at the feeder of a glass forming machine. The granules are made by coating or wetting an alkali metal nitrate with sodium silicate aqueous solution. They decompose in the melt, but the water glass coating slows the decomposition rate such that the resulting gas inclusions cannot escape from the melt before it has been formed or set in a desired shape in the forming machine.

Abstract: Finely divided glass, which may have a viscosity between 10.sup.6 and 10.sup.7 poises at 950.degree.C to 1100.degree.C and which may be of a composition suitable to conversion into a vitroceramic, is mixed with up to a few percent by weight of a foaming agent including a mixture of SnO.sub.2 and SiC, in equimolar proportions or with an excess of SiC. The resulting mixture is heated to 950.degree.C to 1100.degree.C to effect foaming by evolution of CO.sub.2 from the foaming agent, and the resulting glass foam is cooled. The nucleation and crystallization steps by which the glass is converted to a vitroceramic may be caused to occur without allowing the foam to return to room temperature.

Abstract: Improved production of alkali metal silicate glass is achieved by vigorous steam bubbling through the molten glass bed during the preparation of glass by fusion. Such practice results in higher production using less fuel and the product glass is easier to dissolve and results in solutions of greater clarity.

Abstract: A foam glass is manufactured by mixing silicate glass, a volcanic glass material (volcanic ashes of a special chemical composition, occurring in the Kyushu District of Japan), water glass and at least one member selected from the group consisting of sodium salts and calcium salts of phosphoric acid, firing the resultant mixture into a fused state and cooling the fused mixture. The foam glass has a high aluminum content, contains numerous fine bubbles less than 1.5mm in diameter, has a bulk density of less than 1 and shows excellent mechanical strength such as, for example, high bending strength.

Abstract: A lightweight refractory foam primarily of silica can be formed from a phase-separable silicate glass such as borosilicate glass, by melting the glass, foaming the glass at elevated temperatures, phase-separating the silicate foam glass at elevated temperatures to form a silica-rich phase and a silica-poor phase and leaching said phase-separated foam glass with warm water or dilute acids to remove substantially the silica-poor phase. The resulting refractory foam consists essentially of a silica network. The density of the refractory cellular product may be from about 0.075 grams per cubic centimeter to 0.5 grams per cubic centimeter, or higher, as desired. The refractory cellular product has a very low coefficient of expansion and high chemical durability.

Abstract: Scrap glass is crushed and mixed with selected quantities of ball clay and wollastonite, the resulting raw-mix is press-molded into a green compact, and the latter is fired in air at a temperature above the softening point of the glass particles to provide a ceramic article that has a dense impervious structure and is electrically non-conductive. Selective amounts of bentonite and an inorganic pigment can also be included in the raw-mix formulation and talc, petalite or potter's flint can be substituted for the wollastonite. By properly correlating the molding pressure and firing schedule with the raw-mix formulation, the ceramic articles can be rapidly and economically mass-produced in various shapes and sizes.