Pyrometallurgical recovery of zinc and valuable metals from electric arc furnace dust - A review

Electric arc furnace dust (EAFD) has attracted more and more attention as a kind of metallurgical solid waste with huge production. How to reduce its harm to the environment and efficiently recover valuable metals such as zinc, lead and iron from its complex components to realize the comprehensive utilization of EAFD is the aim of various EAFD treatment processes. In this paper, the physical and chemical properties of EAFD are discussed from the micro and macro perspectives, the microstructure, chemical composition and phase composition of EAFD in various countries are summarized in detail. According to the zinc content, EAFD can be divided into three types: high-zinc, medium-zinc and low-zinc. The results show that Fe, Ni, Cr and other elements increase with the decrease of zinc content in EAFD. Not only the zinc oxide but also abundant Fe-Ni-Cr alloy of high value can be recycled from the low-zinc EAFD, which provides guidance for EAFD treatment. At the same time, the general mechanism of direct reduction and smelting reduction pyrometallurgical processes of EAFD is expounded, and the existing pyrometallurgical processes such as rotary kiln process, rotary hearth furnace process, Primus process, ESRF process and Coke-packed bed process are summarized and compared from the aspects of energy consumption, production capacity, process flow to actual application status. In addition, the properties of directly reduced iron and zinc-rich dust obtained by pyrometallurgical processes of EAFD are also discussed. Finally, a new process of treating EAFD by combining direct reduction process and smelting reduction process is proposed to overcome the defects existing in two types of pyrometallurgical processes, and the development of preparing zinc oxide micropowder and high valued Fe-Ni-Cr alloy by pyrometallurgical process of EAFD is prospected. (c) 2021 Elsevier Ltd. All rights reserved.