Abstract: A quartz glass body and a process for the preparation of a quartz glass body is disclosed. One process includes providing a silicon dioxide granulate from a pyrogenic silicon dioxide powder, making a glass melt out of the silicon dioxide granulate and making a quartz glass body out of at least part of the glass melt. In at least one process a silicon component different from silicon dioxide is added. A quartz glass body is obtainable by this process. A light guide, an illuminant and a formed body, are each obtainable by further processing of the quartz glass body.

Abstract: A process for the production of a fluorinated quartz glass including the steps of generating SiO2 particles in a synthesis burner; depositing the resulting SiO2 particles into a body; and vitrifying the resulting body, wherein a fluorinating agent having a boiling point greater than or equal to ?10° C. is supplied to the synthesis burner.

Abstract: Methods are known for producing an anti-resonant hollow-core fiber which has a hollow core extending along a fiber longitudinal axis and an inner jacket region that surrounds the hollow core, said jacket region comprising multiple anti-resonant elements. The known methods have the steps of: providing a cladding tube that has a cladding tube inner bore and a cladding tube longitudinal axis along which a cladding tube wall extends that is delimited by an interior and an exterior; providing a number of tubular anti-resonant element preforms; arranging the anti-resonant element preforms at target positions of the interior of the cladding tube wall, thereby forming a primary preform which has a hollow core region and an inner jacket region; further processing the primary preform in order to form a secondary preform, including an elongation process; and drawing the secondary preform in order to form the hollow-core fiber.

Abstract: In a method of manufacturing a tube of quartz glass by molding a hollow cylinder having a wall thickness of at least 20 mm, the cylinder is continuously fed under rotation about a rotational axis into a heating zone at a relative feed rate VC, softened and radially expanded under the effect of a gas pressure. A tube strand is continuously formed and is withdrawn at a withdrawal rate VT. In order to mold thick-walled initial hollow cylinders of quartz glass into tubes with larger diameter, the gas pressure is used as an actuating variable of a diameter regulation for the tube outer diameter or for a geometrical correlated parameter thereof, and in a pressure build-up phase the gas pressure is gradually increased from a lower initial value to a higher final value, and that the following applies to the ratio of VC and VT:VT=VC±0.2·VC.

Abstract: A process for producing a fluorinated quartz glass is described, including providing an SiO2 soot body; reacting the SiO2 soot body with a fluorinating agent having a boiling point of greater than or equal to ?10° C. to obtain a fluorinated SiO2 soot body; and vitrifying the fluorinated SiO2 soot body.

Abstract: Described is a process for the refinement of a quartz powder, comprising the step of separating microparticles of refractory minerals, in particular minerals containing rare earth metal compounds, from the quartz powder by an elutriation step.

Abstract: One aspect is a method for producing a multilayered silica glass body. The method involves producing a multilayered silica glass body in which a transparent silica glass layer is provided on the surface of a siliceous substrate made of a siliceous material. The method includes preparing the siliceous substrate, preparing a silica slurry in which silica particles are dispersed in a liquid, applying the silica slurry to the surface of the siliceous substrate, leveling the silica slurry applied to the surface of the siliceous substrate by applying vibration to the siliceous substrate, drying the leveled silica slurry, and vitrifying the dried silica slurry by heating to form a transparent silica glass layer. As a result, a transparent silica glass layer of uniform thickness is obtained at excellent yield, and a method for producing a multilayered silica glass body easily in a short time is provided.

Abstract: An apparatus and related process for producing a high-strength weld between two glass components. Chucks clamp and move respective first ends of the glass components toward each other inside an enclosure, where the second ends are heated, softened, and welded together in a weld zone. The enclosure has layers of stacked quartz glass bricks and allows the weld zone to cool slowly and avoid stress. A propane quartz melting torch directs a flame inside the enclosure and toward the second ends as the glass components move toward each other. The flame softens the second ends and creates substantially smooth polished surfaces in the weld zone having an increased hydroxide content. At least 80% of the weld zone has a hydroxide content greater than about 10 ppm average in a 10 ?m depth from the surface and the tensile strength of the weld zone is above about 10 MPa.

Abstract: One aspect relates to a process for the preparation of a quartz glass body, including providing a silicon dioxide granulate, wherein the silicon dioxide granulate was made from pyrogenic silicon dioxide powder and the silicon dioxide granulate has a BET surface area in a range from 20 to 40 m2/g, making a glass melt out of silicon dioxide granulate in an oven and making a quartz glass body out of at least part of the glass melt. The oven has at least a first and a further chamber connected to one another via a passage. The temperature in the first chamber is lower than the temperature in the further chambers. On aspect relates to a quartz glass body which is obtainable by this process. One aspect relates to a light guide, an illuminant and a formed body, which are each obtainable by further processing of the quartz glass body.

Abstract: In a known method for treating pourable, inorganic grain, a heated rotary tube is used that rotates about an axis of rotation and surrounds a treatment chamber that is divided into a plurality of treatment zones by means of separating elements. The grain is supplied to the treatment chamber at a grain inlet side and is transported, in a grain transport direction, to a grain outlet side and is exposed to a treatment gas in the process. In order, proceeding herefrom, to allow for reliable and reproducible thermal treatment of pourable inorganic grain, in particular SiO2 grain in the rotary kiln, in a manner having low and effective consumption of treatment gas, it is proposed for spent treatment gas to be suctioned out of a reaction zone of the treatment chamber, by a gas manifold that rotates about the longitudinal axis thereof.

Abstract: A method for homogenizing glass includes the method: providing a cylindrical blank composed of the glass having a cylindrical outer surface that extends along a longitudinal axis of the blank between a first end face and a second end face, forming a shear zone in the blank by softening a longitudinal section of the blank and subjecting it to a thermal-mechanical intermixing treatment, and displacing the shear zone along the longitudinal axis of the blank. The displacement of the shear zone along the longitudinal axis of the blank is superimposed by a simultaneous oscillating motion of the shear zone along the longitudinal axis of the blank. The first end of the blank is rotated at a first rotational speed and the second end of the blank is rotated at a second rotational speed. An oscillating motion of the shear zone is generated by periodically varying the first and/or second rotational speed.

Abstract: Producing a molded body made of opaque quartz glass includes providing SiO2 grains obtained by comminuting quartz glass having a purity of at least 99.9 wt % SiO2, forming a slurry containing a suspension liquid and the SiO2 grains and which has a total solids content, wet grinding the SiO2 grains in the slurry so as to form ground SiO2 grain particles, forming a porous green body from the slurry, and sintering the porous green body. To provide a low cost quartz glass, the wet grinding of the SiO2 grains takes place at least temporarily in the presence of SiO2 nanoparticles, the proportion of which in the total solids content of the slurry is in the range of 0.1 wt % to 10 wt %, and the slurry has a solids content in the range of 76 to 80 wt % after addition of the SiO2 nanoparticles and after the wet grinding.

Abstract: Known heating burners for producing a welded joint between components of quartz glass include a burner head in which at least one burner nozzle is formed, a burner-head cooling system for the temperature control of the burner head and a supply line connected to the burner nozzle for a fuel gas. Starting from this, to modify a heating burner in such a way that impurities in the weld seam between quartz-glass components to be connected are largely avoided, it is suggested that the burner head should include a base body of silver or of a silver-based alloy.

Abstract: In known methods for producing a glass component, a void-containing intermediate product containing doped or non-doped SiO2 is inserted into a sheath tube composed of glass, which has a longitudinal axis and an inner bore, and is thermally treated therein. In order to subject the intermediate product to a thermal and/or reactive treatment that is reproducible and uniform in its effect from this starting point, it is proposed in one embodiment that into the sheath tube's inner bore a first gas-permeable gas diffuser is inserted which is displaceable along the sheath tube's longitudinal axis and is pressed against the intermediate product during the thermal treatment.

Abstract: One aspect relates to a process for the preparation of a quartz glass body. The process includes providing silicon dioxide particles, making a glass melt out of the silicon dioxide particles in an oven and making a quartz glass body out of at least part of the glass melt. The oven has a gas outlet through which gas is removed from the oven, wherein the dew point of the gas on exiting the oven through the gas outlet is less than 0° C. One aspect further relates to a quartz glass body which is obtainable by this process. One aspect further relates to a light guide, an illuminant and a formed body, which are each obtainable by further processing of the quartz glass body.

Abstract: One aspect relates to a process for the preparation of a quartz glass body including, providing a silicon dioxide granulate obtainable from a silicon dioxide powder, wherein the silicon dioxide granulate has a larger particle size than the silicon dioxide powder, making a 5 glass melt out of silicon dioxide granulate and making a quartz glass body out of at least part of the glass melt. The melting crucible has at least one inlet and at least one outlet. A least part of the glass melt is removed via the melting crucible outlet. One aspect further relates to a quartz glass body which is obtainable by this process. One aspect further relates to a light guide, an illuminant and a formed body, which are each obtainable by further processing 10 of the quartz glass body.

Abstract: Provided is a heat reflective member, which is prevented from braking even in a high-temperature environment. It generates no dust in use, and can be washed with a chemical liquid. The heat reflective member has a laminated structure in which quartz glass layers are formed on an upper surface and a lower surface of a siliceous sintered powder layer. The heat reflective member includes: an impermeable layer which is formed at a portion of the siliceous sintered powder layer at an end portion of the heat reflective member, which has a thickness at least larger than half of a thickness of the siliceous sintered powder layer, and through which a gas or a liquid is prevented from penetrating; and a buffer layer which is formed between the impermeable layer and the siliceous sintered powder layer, and which changes in density from the impermeable layer toward the sintered powder layer.

Abstract: In a known method for producing a quartz glass component, a crystal formation layer containing a crystallization promoter is produced on a coating surface of a base body of quartz glass. Starting therefrom, to provide a method for producing a quartz glass component of improved thermal strength and long-term stability which displays a comparatively small deformation particularly also in the case of rapid heating-up processes, it is suggested according to one aspect that a porous crystal formation layer containing amorphous SiO2 particles is produced with a mean thickness in the range of 0.1 to 5 mm, and that a substance which contains cesium and/or rubidium is used as the crystallization promoter.

Abstract: A method for homogenizing glass includes the method: providing a cylindrical blank composed of the glass having a cylindrical outer surface that extends along a longitudinal axis of the blank between a first end face and a second end face, forming a shear zone in the blank by softening a longitudinal section of the blank and subjecting it to a thermal-mechanical intermixing treatment, and displacing the shear zone along the longitudinal axis of the blank. To enable a radial mixing within the shear zone in addition to the tangential mixing with the lowest possible time and energy input, starting from this method, cylindrical sections of the blank are adjacent to the shear zone on both sides, the first cylindrical section having a first central axis and the second cylindrical section having a second central axis, the first central axis and the second central axis being temporarily non-coaxial with each other.

Abstract: One aspect is a reflective member, which has a laminated structure in which transparent quartz glass members are formed on an upper surface and a lower surface of an opaque siliceous sintered powder layer. The opaque siliceous sintered powder layer has a thickness of 0.1 mm or more and a thickness distribution of ±0.05 mm or less. When a load is applied to each of the transparent quartz glass members on an upper surface and a lower surface of the laminated structure in a direction parallel to the laminated structure, the reflective member is fractured at a load of 5 N or more per square centimeter. The laminated structure includes a semi-transparent portion having a width of 0.01 mm or less, which has an intermediate opacity between an opacity of the opaque siliceous sintered powder layer and an opacity of each of the transparent quartz glass members.