Quarzglastiegel und Verfahren für seine Herstellung

摘要

The invention relates to a crucible characterized in that said crucible is of high purity and high opacity or exhibits low transmission characteristics in the IR range and is derived from a quartz glass crucible known in prior art. Said crucible known in prior art has a crucible body which is symmetrical about a rotational axis and said body is made of opaque quartz glass, whereby the crucible has an outer zone (3) made of opaque quartz glass which projects radially inwards to an inner zone (2) made of transparent quartz glass having a density of at least 2.15 g/cm<3>. The crucible body (1) is made of a synthetic SiO2 granulate with a specific surface (according to BET) in the range of 0.5 m<2>/g to 40 m<2>/g and having a stamp density of at least 0.8 g/cm<3> and is produced from an at least partially porous agglomerate of SiO2 primary particles. A method for producing said quartz glass crucible is characterized according to the invention in that during the production of said crucible, an at least partially porous agglomorate of synthetically produced SiO2 granulate made of SiO2 primary particles is produced having a specific surface (according to BET) in the range of 0.5 m<2>/g to 40 m<2>/g and a stamp density of at least 0.8 g/cm<3>. Heating is performed in such a manner that a vitrification front progresses from the inside to the outside of an inner zone (4) made of transparent quartz glass.