METHOD FOR TREATING A LEAD-CONTAINING LADLE SLAG

摘要

PROBLEM TO BE SOLVED: To reduce the lead concentration of a lead-containing ladle slag and to concomitantly cut down on the to-be-discarded quantity of the slag per se.SOLUTION: A lead-containing ladle slag is used as a converter blowing auxiliary ingredient. On this occasion, the quantity of the lead-containing ladle slag used as a converter blowing auxiliary ingredient is limited at or below the mass calculated in compliance with the following formula (1) and formula (2) in such a way that the concentration of Pb included within a converter-blown molten steel will be equal to or lesser than the standard concentration of an iron steel product manufactured by using the molten steel [Pb] and that the concentration of Pb within a converter-blown intra-converter slag (Pb) will be equal to or lesser than a concentration stipulated by an environmental standard. In these formulae, X is the lead concentration of the ladle slag (mass%); A is the weight of the ladle slag used (ton); B is the molten pig iron weight (ton); C is the auxiliary ingredient weight (ton); a is the Pb distribution ratio (=(Pb)/[Pb]); b is the Pb vaporization throughput (%): (Pb)>(A×X)(1-b)/{B/a+(A+C)} (1); [Pb]>(A×Y)(1-b)/{B+a×(A+C)} (2).