With every tonne of pig iron being produced, over 10 kg of flue dust is generated. Direct recycling of this material is unacceptable mainly due to its high zinc content. This waste often ends up on landfills, which is not ideal because of its heavy metal content and fine-grained character. There are several pyrometallurgical methods for recycling this type of material, but due to high energy consumption and low zinc content it’s not ideal choice. On the other hand, hydrometallurgy is suitable for low zinc content with possibility of selective leaching. In this work, leaching of the dust with sulphuric acid was observed. Thermodynamic and kinetic aspects of zinc leaching were studied. Experiments were carried out under atmospheric pressure and effect of acid concentration and temperature was investigated. The goal was to set the conditions for maximum zinc leaching while minimum amount of iron is transferred into solution. Ideal conditions for selective leaching were achieved using 50 °C and 1 ÷ 0.5 M sulphuric acid solution. Higher temperature and concentration caused higher iron leaching ratio. With optimal conditions, iron recovery was in the range 5 ÷ 10 % while all of the zinc was leached out. Solid residue, obtained by this method is relatively zinc-free and can be reused in blast furnace (BF) process.Keywords: Zinc, blast furnace flue dust, leaching, hydrometallurgy, material recycling
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