Ural Federal University named after the First President of Russia B.N. Yeltsin, Ekaterinburg, Russia

D. I. Bludova, Assistant of the Department of Non-Ferrous Metals Metallurgy, Institute of New Materials and Technologies, e-mail: dana.bludova@urfu.ru
S. V. Mamyachenkov, Professor, Head of the Department of Nonferrous Metals Metallurgy, Institute of New Materials and Technologies, e-mail: s.v.mamiachenkov@urfu.ru

From an environmental point of view, dust from the melting of galvanized steel scrap in electric arc furnaces is a problematic waste stream. In particular, it is impossible to store dust in open areas due to high content of toxic components (lead, zinc, cadmium, etc.). At the same time, the extraction of non-ferrous metals from electric-arc melting dust can make it a valuable source of secondary raw materials and reduce the impact on the environment. In a laboratory study, zinc was extracted from electric arc smelting dust by a chlorination method with a waste halogencontaining polymer. Roasting of galvanized scrap melting dust together with polyvinyl chloride (PVC) waste as a chlorination agent at 950 °C resulted in the evaporation of about 80 wt.% zinc in an oxidizing atmosphere and more than 95 wt.% zinc in a neutral atmosphere. The use of PVC waste in the firing process provides the release of gaseous HCl, which is an effective reagent for the chlorination of zinc compounds in dusts. The presence of solid carbon from polymer pyrolysis in the mixture accelerates the course of chlorination reactions, which is confirmed by the thermodynamic calculations given above. Energy dispersive X-ray spectroscopy of the cinder obtained by roasting at 950 °C in a neutral atmosphere showed that the dry residue of the material in the proposed process does not contain zinc.

1. Toporkova Yu. I., Bludova D., Mamyachenkov S. V., Anisimova O. S. A Review of Processing Methods for Electric Arc Furnace Dust. iPolytech Journal. 2021. Vol. 25, Iss. 5. pp. 643–680.
2. Wang S.-J., He P.-J., Lu W.-T., Shao L.-M., Zhang H. Comparison of Pb, Cd, Zn, and Cu Chlorination During Pyrolysis and Incineration. Fuel. 2017. Vol. 194. pp. 257–265.
3. Lu X. L., Wei L., Liu Y. S. Effect of Chlorine-Containing Compounds on Evaporation of Heavy Metals in Secondary Gasification of Fly Ash From Municipal Solid Waste Incinerator. Acta Scientiarum Naturalium Universitatis Pekinensis. 2012. Vol. 48, Iss. 1. pp. 133–138.
4. Nowak B., Rocha S. F., Aschenbrenner P. Heavy Metal Removal from MSW Fly Ash by Means of Chlorination and Thermal Treatment: Influence of the Chloride Type. Chemical Engineering Journal. 2012. Vol. 179, Iss. 1. pp. 178–185.
5. Wang X.-T., Xu B., Zhao D.-N., Jin B.-S. Experimental Analysis of Heavy Metals Behavior During Melting Process of Fly Ashes from MSWI Under Different Atmospheres. 4^th International Conference on Bioinformatics and Biomedical Engineering, Chengdu, China, 18–20 June 2010. pp. 1–4.
6. Giergiczny Z., Król A. Immobilization of Heavy Metals (Pb, Cu, Cr, Zn, Cd, Mn) in the Mineral Additions Containing Concrete Composites. Journal of Hazardous Materials. 2008. Vol. 160, Iss. 2-3. pp. 247–255.
7. Kanari N., Gaballah I., Allain E. A Low Temperature Chlorination–Volatilization Process for the Treatment of Chalcopyrite Concentrates. Thermochimica Acta. 2001. Vol. 373, Iss. 1. pp. 75–93.
8. Kageyama H., Osada S., Nakata H., Kubota M., Matsuda H. Effect of Coexisting Inorganic Chlorides on Lead Volatilization from CaO – SiO₂ – Al₂O₃ Molten Slag Under Municipal Solid Waste Gasification and Melting Conditions. Fuel. 2013. Vol. 103. pp. 94–100.
9. Gustafsson A. M. K., Steenari B.-M., Ekberg C. Recycling of CIGS Solar Cell Waste Materials — Separation of Copper, Indium and Gallium by High-Temperature Chlorination React ion with Ammonium Chloride. Separation Science and Technology. 2015. Vol. 38. pp. 2415–2425.
10. Yu J., Sun L., Ma C., Qiao Y., Xiang J., Hu S., Yao H. Mechanism on Heavy Metals Vaporization from Municipal Solid Waste Fly Ash by MgCl₂₆H₂O. Waste Management. 2016. Vol. 49. pp. 124–130.
11. Kurashima K., Matsuda K., Kumagai S., Kameda T., Saito Y., Yoshioka T. A Combined Kinetic and Thermodynamic Approach for Interpreting the Complex Interactions During Chloride Volatilization of Heavy Metals in Municipal Solid Waste Fly Ash. Waste Management. 2019. Vol. 87. pp. 204–217.
12. Santos F., Brocchi E., Araújo V., Souza R. Behavior of Zn and Fe Content in Electric Arc Furnace Dust as Submitted to Chlorination Methods. Metallurgical and Materials Transactions: B. 2015. Vol. 46. P. 1729–1741.
13. Masuda Y., Uda T., Terakado O., Hirasawa M. Pyrolysis Study of Poly(vinyl chloride)–Metal Oxide Mixtures: Quantitative Product Analysis and the Chlorine Fixing Ability of Metal Oxides. Journal of Analytical and Applied Pyrolysis. 2006. Vol. 77, Iss. 2. pp. 159–168.
14. Yoo J.-M., Kim B.-S., Lee J-C., Kim M.-S., Nam C.-W. Kinetics of the Volatilization Removal of Lead in Electric Arc Furnace Dust. Materials Transaction. 2005. Vol. 46, Iss. 2. pp. 323–328.
15. Yuan G., Chen D., Yin L., Wang Z., Zhao L., Wang J. Y. High Efficiency Chlorine Removal from Polyvinyl Chloride (PVC) Pyrolysis with a Gas-Liquid Fluidized Bed Reactor. Waste Management. 2014. Vol. 34, Iss. 6. pp. 1045–1050.
16. Yoshioka T., Saitoh N., Okuwaki A. Temperature Dependence on the Activation Energy of Dechlorination in Thermal Degradation of Polyvinylchloride. Chemical Letters. 2005. Vol. 34, Iss. 1. pp. 70–71.