Pyrometallurgical recycling of electric arc furnace dust

Electric arc furnace (EAF) dust is an important secondary resource which contains multiple metallic elements, such as zinc, lead, iron, chromium and cadmium. Recycling of EAF dust is not only favorable to increasing economic potential of the dust by recovering these valuable metals, but also of benefit to solving disposal and environmental problems caused by the heavy metals (e.g., lead, chromium and cadmium) entrained in the dust. Among the existing processes and those under development, pyrometallurgical routes are considered the primary choice for processing of EAF dust because of its high potential metal recovery, easy treatment of residue and relatively short flow sheet. In this paper, the authors reviewed the chemical and physical properties of EAF dust and its thermodynamic characteristics in pyrometallurgical processing, followed by an in-depth discussion of a variety of the pyrometallurgical processes for recycling of the dust, including Waelz kiln process, rotary hearth furnace (RHF) process, PRIMUS process, OXYCUP process, coke-packed bed process, Ausmelt process, electric smelting reduction furnace (ESRF) process, Plasamadust process, plasma-arc process, Elkem multi-purpose furnace (EMPF) process, submerged plasma process, pig iron zinc oxide (PIZO) process, flame reactor process, thermal plasma reduction process, microwave processing, solar thermal reduction process, iron bath smelting process, calcification process and halogenation process. Particular attention is devoted to specific technical challenges emerging in the pyrometallurgical processing of EAF dust and to the corresponding potential measures for improving the dust recycling by promoting the processing efficiency with elimination of secondary hazardous pollutants.