STEEL SMELTING BY OXYGEN CONVERTER METHOD FROM VANADIUM-CONTAINING CAST IRON

Abstract

The results of BOF steel smelting from vanadium-containing cast iron obtained by smelting metallized pellets from titanomagnetite ore of the Tebinbulak deposit in a high temperature tube furnace (Gero HTRV 200-250/17) are presented in the study. Studies were carried out on devanadization and decarbonization of cast iron under the conditions of BOF process in a vertical high-temperature tube furnace. The study presents a description of the scheme of the experimental setup and the methodology of research, which were carried out on the basis of Research Center of the Montanuniversitaet of Leoben (MUL, Austria, Leoben). The samples of cast iron with different chemical compositions obtained by smelting experimental batches of metallized pellets in submerged arc furnace were used in the tests of BOF process. The temperature was 1450°C in the first quarter and 1550°C in the last quarter of the test. The tests showed that the elements transition from the metal phase to the slag phase according to their standard free energies of oxide formation. The titanium and silicon content decreased to almost null values during the first 12,5% of the total blowing time. The content of manganese and vanadium decreased more slowly, but at the end of the tests they also entered the slag phase. The carbon content can be reduced from 4,5% to almost null values. The quantity of slag was small and as a consequence making it difficult to separate the slag from metallic phase, as a result the slag phase contained about 70% FeO. In similar industrial processes, the FeO content is about 25%, which means that the content of other elements is overestimated by almost three times. The values of vanadium oxide content in the slag obtained during smelting by the oxygen-converter method amounted to 6,2% and 8,41%. The excess of three times is consistent with the vanadium content of about 20% and with 25% FeO in the slag phase. The tests have confirmed the suitability of the vanadium-containing cast iron from titanomagnetite ore of the Tebinbulak deposit in the production of steel by the oxygen converter process.