METHOD OF PROCESSING METALLURGICAL PRODUCTION WASTE Russian patent published in 2017 - IPC C22B7/02 C21B11/06 C22B19/38 

FIELD: metallurgy.

SUBSTANCE: iron and zinc-containing dust, milling scale, carbonaceous reducing agent and slag forming components are mixed, agglomerated, dried and heat-treated in a rotary-hearth kiln. Zinc sublimations are captured, the exhaust gases are cooled. Oxidation and condensation of zinc oxide in the form of dust and trapping of dust containing zinc oxide are carried out. Granulated cast iron and slag are cooled and separated. The ratio of dust and scale is set to provide total iron content in the mixture of at least 50%. The slag forming components are introduced in an amount providing the basicity of CaO/SiO₂ in range of 0.6-1.6 and the sulfur content in cast iron is not more than 0.09. The carbonaceous reductant is introduced in an amount providing carbon content in the cast iron ranging from 1.0 to 4.5%. Heat treatment is carried out by two-stage heating: at 1200-1300°C, then at a temperature increased by 80-200°C.

EFFECT: increasing the content of zinc oxide in concentrate extracted from dust and scale, obtaining cast iron with metallic iron content of 94 percent or more, reducing the consumption of reducing agent and fuel.

3 cl, 1 dwg, 1 tbl, 1 ex