Development of On-line Analysis Method for Determination of Chromium in Molten Stainless Steel in LD Converter

摘要

An on-line analytical method based on the hotspot radiation spectrometry was applied to the determination of chromium in molten stainless steel in a converter. In this study, the following points were discussed in order to develop an on-line and real-time monitoring method for chromium concentration in molten stainless steel. The first is that the atomic emission intensity of chromium at the hotspot is expected to be weak because its atomic vapor pressure is rather low. The second is the severe self absorption effects on the chromium determination, because its concentration in the stainless steel is about 10 to 20 percent. The third is the possibility of the spectral interferences because there are strong emission lines of iron very close to the analytical line of chromium. Finally, the formation of the very hard slag with Cr_2O_3 may interfere to from the hotspot properly. Consequently, the modification of the spectral measurement system and the development of data analytical procedure make it possible to determine chromium concentration in molten stainless steel with the analytical precision of CV=7 percent.