METHOD OF REMOVING CHROMIUM AND/OR NICKEL FROM LIQUID SLAGS Russian patent published in 2004 - IPC

FIELD: ferrous metallurgy.

SUBSTANCE: method comprises supplying liquid slags containing chromium and/or nickel oxides into molten pool and two-step reduction of slags. In the first step, reduction is accomplished by injecting carbon into molten pool to reduce content of chromium and/or nickel oxides in slags to a value from 0.8 to 0.2%. In the second reduction step, to reduce content of chromium and/or nickel oxides in slag below 0.15%, preferably below 0.08%, higher reduction potential is created by way of adding into slag reducing agents with higher reduction potential such as aluminum, calcium, silicon, ferrosilicon, silicocalcium. Ferrosilicon is added in amounts 3 to 15 kg per 1 t slag, preferably 6-10 kg/t. Once reducing agents with higher reduction potential is added, molten pool is flushed with inert gas. First reduction step lasts 15-30 min and the second 3-10 min.

EFFECT: increased reliability of removing chromium and/or nickel so that slags can further be used as ground cement materials and reduced total treatment time.

4 cl, 3 tbl