Separation of iron and zinc components dust of gas cleaning devices of the electric steelmaking productions

Abstract

Currently, the volumes of use of dust from gas-cleaning devices (DGD) of electric steel furnaces are extremely insignificant, as they have an impact on the environment during storage, but at the same time, they represent the material that has a valuable composition (oxides of iron, non-ferrous metals, etc.) and is promising for recycling. However, the secondary use of zinc-containing DGD in ferrous metallurgy leads to the accumulation of zinc in the lining of blast furnaces and frequent malfunctions. It has been established that zinc oxide remains mainly in the bound state in the franklinite phase (Zn,Mn,Fe)(Fe,Mn)2O4. The processes of solid-phase reduction of dust from gas-cleaning devices of electric steel furnaces with the production of zinc concentrate and sponge iron, that are raw materials in demand for non-ferrous and ferrous metallurgy, are studied. The optimal conditions for the reduction process were determined, the physicochemical characteristics, granulometric and phase composition of the starting materials and reduction products were studied. It has been established, that the use of a combination of reducing agents of different nature (coal coke and H2) during heat treatment at 1100 °C and cooling in a reducing medium (Ar/H2) makes it possible to obtain sponge iron with a high degree of metallization - 97,5 %.