Preparation of a quartz glass body in a melting crucible of refractory metal

A process for preparing a quartz glass body comprising pyrogenic silicon dioxide, comprising:

• providing a silicon dioxide granulate comprising:
• providing a pyrogenic silicon dioxide powder;
• and
• processing the silicon dioxide powder to give a silicon dioxide granulate,
• wherein the silicon dioxide granulate has a larger particle diameter than the silicon dioxide powder;
• making a glass melt from the silicon dioxide granulate in a melting crucible;
• and
• making a quartz glass body from at least a part of the glass melt;
• wherein the melting crucible is comprised in an oven,
• wherein the melting crucible is made of at least one material comprising tungsten or molybdenum or a combination thereof, and
• wherein the quartz glass body comprises:
• an OH content of less than 500 ppm;
• a chlorine content of less than 60 ppm;
• a tungsten content of less than 1000 ppb;
• a molybdenum content of less than 1000 ppb;
• wherein the ppb and ppm are based on the total weight of the quartz glass body in each case.