1991 Volume 77 Issue 6 Pages 805-811
Recently, there are great demands for the development of direct analysis methods for molten iron in order to monitor the reactions of in steel making processes. In this paper, the new on-line analysis method for manganese in molten iron is developed and the theoretical background of the method is clarified. The analytical method realizes the real-time and continuous measurement of manganese concentration during the decarbonization process in a converter. This method is based on the measurement of atomic emission spectra of manganese and iron radiated at the high temperature zone called "hotspot", which is formed on the surface of molten iron when the oxygen gas jet impinges on it for decarbonization.
In the actual analysis, the emission intensity ratio of manganese to iron is measured in order to eliminate the influence of dusts and surface level fluctuation. The ratio has the adequate correlation to manganese concentration, which is represented as follows;
"K'(T)" is a function of the hotspot temperature and "n" is a self-absorption factor. "K' (T)" represents the effect of hotspot temperature on the ratio of the vaporization rate of mangnese and iron from molten iron. There is the fairly good correlation between the manganese concentration obtained by this method and that obtained by the conventional sampling method, and the coefficient of their correlation is 0.942 in the concentration range from 0.26% to 1.09% of manganese.