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 SiO.sub.2 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.

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 m.sup.2/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.

A method for producing fused silica including pre-heating silica sand by passing the silica sand through a gas flame, distributing the pre-heated silica sand to a furnace having an internal temperature of about 1,713 C. or greater to form molten fused silica, and cooling the molten fused silica by flowing the molten silica from the furnace into a water bath to produce fused silica particulates.

Proppants and methods for their preparation are described herein. The proppants can be prepared by a process comprising (a) directing the molten slag material at a temperature above 1300 C. to an atomizing apparatus to output the molten slag material in the form of atomized droplets, (b) projecting the droplets of the molten slag material, wherein a substantial portion of the droplets at least partially solidifies in flight, (c) maintaining the at least partially solidified droplets at a temperature between 700 C. and 1300 C. to provide proppant particles having a crystalline phase; and (d) cooling the proppant particles to below 700 C. Methods for hydraulic fracturing of a well in a subterranean formation having a fracturing stress are also described herein.

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.

A spherical inorganic oxide powder wherein a volume-based cumulative 50% diameter D50 is 4-55 ?m; and in a cross-section of a cured body containing an epoxy resin and the spherical inorganic oxide powder at a mass ratio of 2:1, when a total of 5000 particles with a maximum diameter of 51 ?m or larger are observed in a field of view at 100? magnification using a scanning electron microscope, a total number of air bubbles having a maximum diameter of 1 ?m or larger and smaller than 10 ?m is 40 or fewer and a total number of air bubbles having a maximum diameter of 10 ?m or larger is 30 or fewer.

The present invention concerns a method for manufacturing a proppant for a particular stimulation fluid, or for manufacturing a stimulation fluid for a particular proppant. The present invention also concerns a proppant for hydrocarbon stimulation, wherein the proppant comprises a plurality of amorphous spherical glass particles which have not undergone any further chemical or thermal treatment, a method of preparing the proppant, and uses of the proppant in hydrocarbon stimulation.

One aspect relates to a process for the preparation of a quartz glass body, including providing a silicon dioxide granulate, 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 silicon dioxide granulate is obtained by providing and processing a silicon dioxide powder. One aspect also relates to silicon dioxide granulate, which is obtained by providing a silicon dioxide powder and processing it. 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.

A quartz glass body and a process for the preparation of a quartz glass body is disclosed. In one aspect, the 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. One aspect further relates to a quartz glass body which 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.

The present disclosure is directed to glass spheroids and methods of making these spheroids that have significantly increased resilience to applied pressure and surface scratching. In addition, the present disclosure is directed to tailless Prince Rupert's Drops and methods of making tailless Prince Rupert's Drops.