Heraeus Quartz UK Limited

Heraeus Quarzglas Gmbh & Co Kg

Heraeus Conamic UK Limited

Heraeus Conamic UK Limiied

Saint-gobain Quartz Plc

Ian George Sayce

Alan Mundy

Hamed Aghajani

Richard Benjamin Coapes

Martin Trommer

Eduard Visnow

Peter John Wells

Fabian Schildt

Michael Schindler

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.

Purification of quartz powders by removal of microparticles of refractory materials

An apparatus for the continuous production of hollow quartz-glass ingots, comprising a) a crucible or refractory tank for providing a softened quartz-glass mass having a dieorifice in the bottom of the crucible or refractory tank; b) a mandrel vertically drawing off the softened quartz-glass mass through a die toprovide a hollow quartz-glass ingot; and c) a cutting section for on-line cutting of the hollow quartz-glass ingot to a specificlength, characterized in that the apparatus comprises active means for cooling the internalsurface of the hollow quartz-glass ingot prior to the cutting station.

Continuous production of hollow ingots

The present invention relates to a continuous method for the production of hollow quartz-glass ingots and an apparatus for said method, whereby the hollow quartz-glass ingots are cooled on the internal surface.

One aspect relates to a method for the production of synthetic quartz glass. Moreover, one aspect relates to a polyalkylsiloxane compound, which includes certain specifications with respect to chlorine content, metallic impurities content, and residual moisture, as well as the use thereof for the production of synthetic quartz glass. One aspect also relates to a synthetic quartz glass that can be obtained according to the method of one embodiment.

Method for the manufacture of synthetic quartz glass

Hollow ingots of transparent synthetic vitreous silica glass of external diameter greater than 400 mm and internal diameter greater than 300 mm are disclosed. The ingots are substantially free from bubbles or inclusions greater than 100 &#x3bc;m in diameter, have no more than 100 ppB of any individual metallic impurity, and have chlorine concentration less than 5 ppM. Also disclosed are methods for producing such ingots, in which a porous soot body of density greater than 0.4 g/cmis deposited on an oxidation resistant mandrel. The soot body is dehydrated on a mandrel comprising graphite, carbon fiber reinforced carbon, silicon carbide, silicon impregnated silicon carbide, silicon carbide-coated graphite or vitreous silica, either under vacuum or in the presence of a reducing gas, and then sintered to transparent pore-free glass under vacuum or in an atmosphere of helium.

High purity synthetic silica and items such as semiconductor jigs manufactured therefrom

Processes for the manufacture of a hollow cylindrical porous body of synthetic vitreous silica soot by outside vapor deposition on a mandrel are described, in which the temperature of the mandrel is controlled to be substantially constant throughout the deposition process. In preferred embodiments, the mandrel is composed of metal or metal alloy. Hollow ingots of pure or doped synthetic vitreous silica glass manufactured by such processes are also described.

Production of silica soot bodies

Methods are described for manufacturing silica-based glass, in which silica precursor material is supplied to a synthesis flame in the form of an emulsion. The methods involve the steps of: forming an emulsion of an aqueous phase in a non-aqueous liquid silica precursor material; supplying the emulsion as a spray of droplets into a synthesis flame, whereby the precursor material is converted in the flame into a silica-containing soot; and collecting the soot on a substrate, either as a porous soot body for subsequent consolidation to glass or directly as a substantially pore-free glass.

Manufacture of synthetic silica glass

A method and apparatus for the manufacture of synthetic vitreous silica ingots involves the production of a melt of synthetic vitreous silica in a crucible ( ) within a refractory furnace ( ), and the continuous withdrawal of an ingot ( ) through an orifice ( ) in the wall of the crucible. The silica may be deposited in the crucible by a synthesis burner ( ), which may also serve to maintain the silica above its sintering temperature. The emerging ingot is supported by an arrangement of moveable clamps ( ).

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Stocksfield, United Kingdom

Ian George Sayce