PURPOSE: To provide an immersion free board which prevents slag from sticking on the inside thereof at the time of executing pretreatment of molten iron, and a method for restraining the sticking of slag. ;CONSTITUTION: The lower part of the immersion free board 3 shutting out outer air is immersed into molten iron 1 into a molten iron treating container 2. A lance 4 is inserted into the molten iron in the immersion free board 3 and at least oxygen or oxide and a prescribed treating material are injected to execute the molten iron pretreatment. During the treatment, a nozzle 21 is inserted downward from the upper part of the free board 3, and gas 22 containing oxygen is blown from the nozzle 21 to burn carbon monoxide produced during the treatment. By this method, the sticking of metal and slag on the inner wall of free board is restrained.;COPYRIGHT: (C)1997,JPO
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