| Abstract: | During secondary refining of molten steel, reaction of steel-slag has great influence on the quality of steel. Taking high aluminium steel (Al]≥0.8%) for instance, reaction control of 4Al]+3(SiO2) = 2(Al2O3)+3Si] was discussed by both thermodynamics calculation and industrial experiments. The results show that content of silicon increased sharply when content of SiO2 in slag exceeded 10%. In order to prevent the increment of silicon content and reoxidation for high aluminium steel, reasonable component range of LF refining slag is: %CaO/%Al2O3=1.6-1.9, %SiO2 <10. Results of the industrial experiments indicate that the CaO-Al2O3 based refining slag has strong ability of desulfurization and inclusion absorption. Average desulfurization rate is 80%, and TO] reduces above 50% after refining, with the average sulfur content and TO] about 0.0025% and 11×10-6,respectively, which can meet the requirements of secondary refining and obtain good castability of steel in continuous casting process. |
