Recovery of Zinc and Iron from Steel Mill Dust—An Overview of Available Technologies

Abstract

The global shortage of zinc mines makes the extraction of zinc from zinc-containing wastes a hot research topic. Most kinds of steel mill dust (SMD) cannot be directly returned to the ironmaking and steelmaking processes due to their zinc content. A large amount of SMD produced during steelmaking has become a major challenge for steel plants due to environmental pollution, health issues and land scarcity. Lots of processes for recovering metals from SMD have been developed to comprehensively utilize them and solve these environmental problems. Zinc in SMD can be recovered by these technologies, and the residue can be used as raw material for ironmaking. In this work, the sources and characteristics of SMD from different processes were analyzed firstly. Then, the mechanisms of physical, hydrometallurgical, pyrometallurgical and pyrometallurgy–hydrometallurgy combined processes for SMD disposal are presented, and these methods are compared in terms of energy consumption, process complexity and industrial application. Finally, suggestions and prospects for utilization of SMD are put forward.

Towards the Circularity of the EU Steel Industry: Modern Technologies for the Recycling of the Dusts and Recovery of Resources

“…However, they are robust and generally characterized by a high efficiency of Zn and Fe recovery, as outlined in the discussion reported in the following sections [23]. Recent research widely investigated valid recycling options based on the association of hydrometallurgical and pyrometallurgical steps, to overcome the technical issues linked to the challenging leaching of zinc ferrite (ZnFe 2 O 3 ) [24].…”

“…The Waelz process is currently the most widely used method for recovering those dusts containing medium levels (16-30 wt.%) of zinc; the vast literature may be found about this technology and eventual improvements will be carried out [9,[23][24][25][26][27], and a simplified flow scheme is reported in Figure 3 below. The feed, composed of pelletized Zn-rich dusts/coke/lime agglomerates, enters at the head of the rotating (~1 rpm) and 2-3% inclined Waelz kiln; despite the different designs, it is usually 50 m long with an inner diameter of about 3.5 m. The kiln has a precise temperature profile which is reported in Figure 3 as zone 1 (600 °C), zone 2 (1100 °C), zone 3 (1300 °C), and zone 4 (1000 °C).…”

Multi-Source Ferrous Metallurgical Dust and Sludge Recycling: Present Situation and Future Prospects

“…The wet leaching process is necessary to extract non-ferrous metals from FMDS, but the content of non-ferrous metals such as zinc and lead in metallurgical dust and sludge in China is low, so it is not economical to directly use this process to recover valuable elements from FMDS [78].…”

Zinc Evaporation from Brass Scraps in the Atmosphere of Inert Gas

“…Cupriferous wastes are, e.g., casting waste, copper smelting dusts or flotation tailings. In this area, the offered solutions with regard to zinc removal from these wastes are primarily based on pyrometallurgical [ 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 ] and hydrometallurgical [ 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 ] processes. In hydrometallurgical processes, various leaching materials are applied such as sulphuric acid, hydrochloric acid, acetic acid or ammonia solutions.…”