SLAG CONTAINING INSOLUBLE Pb AND SLAG TREATMENT METHOD FOR INSOLUBILIZING Pb

摘要

PROBLEM TO BE SOLVED: To insolubilize Pb contained in slag that is generated in a Pb- containing steel-making process. SOLUTION: The composition of slag containing at least 0.001 mass % of Pb is adjusted to satisfy an expression (1), (T.CaO)/(SiO2)=1.5, then the slag is separated or removed from the molten steel bath surface, further after the separation or removal thereof, a steam-aging treatment of at least 5 days, or an outdoor storage of at least 90 days is conducted. In the expression, (T.CaO) shows a concentration (mass %) in terms of (CaO) of the total Ca contained in the slag, and (SiO2) shows an in-slag (SiO2) concentration (mass %). By this treatment, the amount of Pb elusion from the slag satisfies the value of the environmental quality standard, and the slag can be put to use as a resource.