Abstract: A process of forming glass balls by treatment of particulate vitreous material and a second material comprising carbon material and a carbonated salt. The process is carried out at a temperature, for the particular particulate vitreous material, which corresponds to a viscosity of from about 10.sup.6 to about 10.sup.3.5 poises with mixing and agitation.The apparatus includes a furnace having a tube (4) adapted to rotate about an horizontal or inclined axis, delivery means (10, 12, 14) to the tube for the materials to be treated, and heating means (8, 20) for heating the tube and the bed of material from both an external and internal location.

Abstract: A process of forming glass balls by treatment of particulate vitreous material and a second material comprising carbon material and a carbonated salt. The process is carried out at a temperature, for the particular particulate vitreous material, which corresponds to a viscosity of from about 10.sup.6 to about 10.sup.3.5 poises with mixing and agitation.The apparatus includes a furnace having a tube (4) adapted to rotate about an horizontal or inclined axis, delivery means (10, 12, 14) to the tube for the materials to be treated, and heating means (8, 20) for heating the tube and the bed of material from both an external and internal location.

Abstract: A method for casting vitreous materials using the lost wax process in which a pattern of the article to be cast is formed with a substance which is vaporized at the casting temperature of the vitreous material. The pattern is embedded in a heat resistant silica compound such as sand which surrounds the pattern to form a casting mold. The sand is contained in a receptacle called a casting shell. The vitreous material is heated to a temperature at which its viscosity is between 20 and 100 poises and the article is cast.