DEVICE AND METHOD FOR MELTING A SUBSTANCE WITH THE OCCURRENCE OF A LOW LEVEL OF CONTAMINATION

摘要

The invention relates to a device and method for melting, with the occurrence of a low level of contamination, a glass or glass-ceramic material that is highly pure, aggressive and/or has a high melting point. According to the invention, a melt is heated in a crucible or a melt-down skull crucible using high-frequency irradiation and is mixed or homogenized in the melt-down crucible. A gas nozzle is preferably provided on the bottom of the crucible out of which gas bubbles, e.g. oxygen bubbles (so called O2 bubbling) are discharged into the melt. This makes it possible to already achieve a surprising multiple utilization inside the melt-down skull crucible. Firstly, the unmelted quantity that falls, for example, from above into the melt in solid form is melted more quickly by the increased thorough mixing thereof with the liquid portion of the melt. Secondly, the temperature distribution of the melt is evened out. Thirdly, the different glass constituents are uniformly distributed or thoroughly mixed and, fourthly, the redox state of the glass can be adjusted.