One aspect relates to a process for the preparation of a quartz glass body. The process includes providing a silicon dioxide granulate from a pyrogenically produced silicon dioxide powder, making a glass melt out of silicon dioxide granulate, and making a quartz glass body out of at least part of the glass melt. The size of the quartz glass body is reduced to obtain a quartz glass grain. The quartz glass body is processed to make a preform and an opaque quartz glass body is made from the preform. One aspect further relates to an opaque quartz glass body which is obtainable by this process. One aspect further relates to a reactor and an arrangement, which are each obtainable by further processing of the opaque quartz glass body.

A method for manufacturing a large sized opaque quartz glass ingot having excellent heat ray shielding and light blocking properties without using a foaming agent. The obtained opaque quartz glass has small diameter spherical bubbles and a preferable mechanical strength. Silica powder is dispersed in water to form a slurry having a silica powder concentration of 45 to 75 wt % and the average particle size of the silica powder is adjusted to 8 μm or less and the standard deviation of the particle size is adjusted to 6 μm or more by wet pulverization. The slurry is sprayed for forming granules of the silica powder. An opaque quartz glass ingot with a small bubble diameter and high mechanical strength is obtained by melting the granulated silica powder.

An article including a glass having that includes SiO.sub.2, Al.sub.2O.sub.3, and B.sub.2O.sub.3 and least one of Li.sub.2O, Na.sub.2O, K.sub.2O, MgO, CaO, SrO, BaO, SnO.sub.2, ZnO, La.sub.2O.sub.3, F, and Fe.sub.2O.sub.3, wherein the glass includes a dielectric constant of about 10 or less and/or a loss tangent of about 0.01 or less, both as measured with signals at 10 GHz.

A process and a plant produce hollow microspheres made of glass. According to the process an aqueous suspension is prepared from starting materials containing glass powder and water glass, feedstock particles having a diameter between 5 μm and 300 μm, in particular between 5 μm and 100 μm, being produced from the suspension. The feedstock particles are mixed with a pulverulent release agent made of aluminum hydroxide in an intensive mixer. The mixture of feedstock particles and release agent is subsequently introduced into a firing chamber of a furnace. The feedstock particles expand in the firing chamber, at a firing temperature which exceeds the softening temperature of the glass powder, to form the hollow microspheres.

An opaque gahnite-spinel glass ceramic is provided. The glass ceramic includes a first crystal phase including (Mg.sub.xZn.sub.1-x)Al.sub.2O.sub.4 where x is less than 1 and a second crystal phase includes at least one of tetragonal ZrO.sub.2, MgTa.sub.2O.sub.6, mullite, and cordierite. The glass ceramic has a Young's modulus greater than or equal to 90 GPa, and has a hardness greater than or equal to 7.5 GPa. The glass ceramic may be ion exchanged. Methods for producing the glass ceramic are also provided.

One aspect relates to a process for the preparation of a quartz glass body. The process includes providing a silicon dioxide granulate I prepared from a pyrogenically produced silicon dioxide powder, treating the silicon dioxide granulate I with a reactant at a temperature in a range from 1000 to 1300° C., and making a glass melt out of the silicon dioxide granulate. A quartz glass body is made out of at least a part of the glass melt. Furthermore, one aspect relates to a quartz glass body obtainable by this process. Furthermore, one aspect relates to a light guide, an illuminant, and a formed body, each of which is obtainable by further processing of the quartz glass body. One aspect additionally relates to a process for the preparation of a silicon dioxide granulate II.

Glass compositions and glass fibers having low dielectric constants and low dissipation factors that may be suitable for use in electronic applications and articles are disclosed. The glass fibers and compositions of the present invention may include between 48.0 to 57.0 weight percent SiO.sub.2; between 15.0 and 26.0 weight percent B.sub.2O.sub.3; between 12.0 and 18.0 weight percent Al.sub.2O.sub.3; between 3.0 and 8.0 weight percent P.sub.2O.sub.5; between 0.25 and 7.00 weight percent CaO; 5.0 or less weight percent MgO; and 6.0 or less weight percent TiO.sub.2. Further, the glass composition has a glass viscosity of 1000 poise at a temperature greater than 1350 degrees Celsius and a liquidus temperature greater than 1100 degrees Celsius.

A glass-ceramic includes SiO.sub.2 in a range of 40 mol. % to 80 mol. %; Al.sub.2O.sub.3 in a range of 5 mol. % to 20 mol. %; MgO in a range of 5 mol. % to 20 mol. %; and at least one of B.sub.2O.sub.3, ZnO, and TiO.sub.2, each in a range of 0 mol. % to 10 mol. %, such that the glass-ceramic further comprises a magnesium aluminosilicate crystalline phase at a concentration in a range of 5 wt. % to 80 wt. % of the glass-ceramic.

Lithium silicate-low quartz glass ceramics are described which are characterized by a combination of very good mechanical and optical properties and can therefore be used in particular as restoration material in dentistry.

The present invention relates to the field of glass manufacturing, and discloses aluminoborosilicate glass, and a preparation method and an application thereof. Based on the total weight of components in the composition of the glass, the glass comprises: 33-60 wt % SiO.sub.2, 3-10 wt % Al.sub.2O.sub.3, 10-30 wt % B.sub.2O.sub.3, 1-15 wt % ZnO+TiO.sub.2+Sc.sub.2O.sub.3, and 7-27 wt % alkaline-earth oxide RO, wherein RO is at least one of MgO, CaO, SrO and BaO, and 0.001 wt %≤Sc.sub.2O.sub.3≤1 wt%. The aluminoborosilicate glass provided in the present invention has advantages including low density, high index of refraction, low thermal expansion coefficient, high thermostability, high flexibility, and easy bending, etc.