A PROCESS FOR KEEPING A TUYERE PASSING THROUGH A METALLURGICAL VESSEL FREE OF A SKULL

摘要

The present invention relates to a process for keeping a tuyere passing through a metallurgical vessel free of a skull by intermittendly passing an oxygen-containing gas through the tuyere to dissolve the skull, wherein it is determined that an interval for passing said oxygen-containing gas through the tuyere needs to be started by detecting electromagnetic radiation emanating from a spot in the interior of the melt by means of a dual wavelength pyrometer and comparing the intensity of the pyrometer signals with the ratio of the pyrometer signals, and initiating said interval for passing said oxygen-containing gas through the tuyere, upon the condition that the combined intensity of the signals falls below a predetermined threshold value and that the ratio of the signals remains substantially constant.