METHOD FOR TAPPING MOLTEN METAL FROM SIMULTANEOUS SMELTING FURNACE FOR ZINC AND LEAD

摘要

PURPOSE:To prevent discharging of the ore contg. Zn at a high rate in the end period of tapping by measuring successively the oxygen potential in the discharged ore in the stage of tapping, setting a specified reference and stopping the tapping. CONSTITUTION:The oxygen potential in furnace in the stage of tapping is measured at a prescribed time interval in a blast furnace for simultaneous smelting of zinc and lead. The tapping is stopped when the final measured value is within a target value or when the next measured value exceeds the value obtd. by adding a predetermined value to the upper limit of the target value if the final measured value is below the target value. The tapping is also stopped when the next measured value exceeds the value obtd. by adding a predetermined value to the first measured value if the final measured value is above the target value. The fluctuation in the average content of zinc in the tapped slag (content of zinc in the slag of the previous hearth) is thus minimized and the content of zinc in the slag is kept low.