Investigation into oxidation of vanadium-containing converter slags using local X-ray spectral analysis

Distribution of vanadium, iron and partially titanium and manganese in the course of oxidation has been studied by the local X-ray spectral analysis. The samples of the slags taken from various melts have been kept in the oxidizing atmosphere at temperatures of 700 deg C when the oxidation degree amounts to 30-35% and changes in distribution of spinelide and silicate are distinctly revealed with the use of the microscope, and at temperature of 800 deg C when spinelide is completely destroyed while the oxidation degree amounts to 90% and over. The microstructure of the slag oxidized at a temperature of 700 deg C for 30 min is shown. According to the results of the local X-ray spectral analysis, spinelide of the original slag contains 35-37% vanadium (50-55% V2O3) and 22-25% iron (30-35% FeO). Silicate does not contain vanadium. The concentration curves of vanadium, iron, titanium and manganese distribution for the profile passing through the field with a high content of spinelides are plotted. At a temperature of 800 deg C spinelides and silicate are fully oxidized. The liquid phase based on vanadium pentoxide grows up and often fills all the pores and cracks of the slag which is rich in vanadium. The composition of the phases is changed and vanadium is distributed throughout the entire sample. However, with regard to the ratio of the components, there are preserved two basic types of the vanadium-content phases: one type is characterized by an increased but alternating content of vanadium and comparatively low content of iron in place of destroyed spinelides, and the other type is characterized by a high content of iron (35-42%) and low content of vanadium (1-6%) in the destroyed silicate phase. In separate sections the phase containing 35-40% iron, 12-14% titanium, but having no vanadium is isolated