Forms of occurrence of selected alloying elements in slag from an electric arc furnace

Abstract

The chemical composition of steel slag is dependent on the type of the charge and thus the alloying elements used in the process. The conducted tests of slag from an electric arc furnace have indicated that their chemical composition contains elements classified as so-called alloying elements – with the highest content of manganese and chromium. Besides these, smaller amounts of cobalt Co, molybdenum Mo, titanium Ti and tungsten W were identified. Due to the significant concentration of Mn and Cr, it was assumed that these elements were added to the alloy on purpose to achieve certain steel properties. The presence of Co, Mo, Ti and W may be related to the type of scrap introduced into the process. To determine what components of the slags are the analysed metals related with, phase composition tests of slag were conducted based on electron scanning microscopy and X-ray diffraction method. It was established that chromium occurs in the form of impurity in the solid solution of FeO-MnO-MgO, called the “RO phase” and forming characteristic dendritic forms. Wolfram, on the other hand, creates its own cryptocrystalline phases classified as tungstates: hübnerite and ferberite. The remaining metals, that is Co, Mo, and Ti occur in a dispersed state in the amorphous substance.