DESILICONIZING METHOD OF MOLTEN IRON

摘要

PURPOSE:To utilize effectively the collected dust recovered from a converter as a desiliconizing agent in the stage of preliminary refining of the desiliconization of a molten iron by subjecting said dust to an oxidation treatment to increase the content of iron oxide. CONSTITUTION:The molten iron from a blast furnace is first desiliconized by preliminary refining prior to dephosphorization and desulfurization treatments. The desiliconization treatment is executed usually by blowing the collected dust from the converter and basic material such as CaO into the furnace through the tuyere thereof and oxidizing Si to desiliconize. However, the collected dust from the converter is spherical and is not angular like sintered ore and therefore such dust causes little damages to the tuyere but the dust contains much metallic iron and little iron oxide and therefore O2 is not enough for the oxidation of the Si. Such dust is therefore heated to 100-400 deg.C and is oxidized by a rotary kiln, fluidized bed, etc., so as to contain the iron oxide at the higher rate. Such dust is blown into the molten iron through the tuyere and the molten iron is desiliconized with high efficiency.