Dissolution behavior of Cu in S-containing molten slags and salts

Abstract

Recycling steel scrap has been one of the major issues in steelmaking societies due to its high potential of boosting enormous productivity of fresh steels. 40% of virgin iron was produced from steel scrap and it is even regarded as secondary iron source today. As for copper, one of the tramp elements causing hot shortness, it is difficult to remove under tolerate constraint of 0.2wt%, for industrial necessities. This challenging topic has been dealt and studied with several treatments but there is no breakthrough yet. One of the practically achievable ways is using sulfur-containing flux. Previous investigations employing the sulfur-containing flux were promising but its bad workability hinders practical application in steelmaking process. Another probable way is utilizing molten oxide slags. Although it has been conceded that oxide slag has relatively lower distribution ability compared to the flux, directly applicable pathways can be suggested once the principle of its dissolution is well-understood. Whereas dissolution reaction of Cu in molten oxide slag has been clearly revealed already by many researchers from copper-making industry, several investigations were shown that there must be another pathways of Cu dissolving for the practical slag conditions where certain amount of S is contained. Present study compares distribution ability of each method (flux and S-containing slag) in terms of distribution ratio(LCu) and its dissolution reaction as well. And thermodynamic effect of each component to its dissolution reactions was discussed.