Abstract: Based on the desulfurization theory and actual production data analysis, the pretreatment desulfurization of silicon steel in a factory was studied. The results showed that the sulfur content of the secondary desulfurization slag was proportional to the sulfur content in the front slag,inversely proportional to the front slag residue, proportional to the primary desulfurization slag residue, and inversely proportional to the amount of desulfurizer. When the total amount of desulfurizer was constant, the sulfur content in the secondary desulfurization slag decreased first and then increased with the increase of the proportion of primary desulfurizer, and the best proportion of primary desulfurizer was  40 % . With the increase of temperature before pretreatment,the sulfur content of molten iron decreased first and then increased, and the optimum temperature before pretreatment was 1 370-1 400 ℃. The sulfur content of hot metal was reduced to 11.7×10^-6 by three times of slag removal and two times of desulfurization, which met the production demand of silicon steel.

Key words: silicon steel, pretreatment, hot metal desulfurization, converter resulfurization