Hydrometallurgical extraction of zinc and iron from electric arc furnace dust (EAFD) using hydrochloric acid

Abstract

Approximately 7.5 million tons of electric arc furnace dust (EAFD) are generated annually worldwide from steelmaking industry. EAFD is categorised as a hazardous waste due to the presence of heavy metals such as zinc, iron, nickel, lead and cadmium. Nevertheless, EAFD can be recycled through the extraction of zinc and iron, which constitute the greatest composition (8%-40% and 16%-60%, respectively) in EAFD. In this project, hydrometallurgical extraction of zinc and iron was performed using hydrochloric acid (HCl) as leaching agent. Factors such as temperature, acid concentration and dust-to-acid ratio on the extraction of zinc and iron were investigated. Results showed that zinc and iron extraction increased simultaneously as the temperature and acid concentration increased. The highest zinc and iron extractions were about 70% and 60%, respectively using 5 M HCl with dust-to-acid ratio of 3 g per 100 ml HCl at 70°C after 15 min of leaching. The result indicates the feasibility of zinc and iron extraction from EAFD through HCl hydrometallurgical process which will be beneficial for steelmaking industries in future.