A new eco-friendly approach for recovery of iron from copper smelting slag: Using CO2 and Cl2 recycling strategies

Abstract

Copper smelting slag (CSS) is a by-product of modern copper production. In this study, iron resources were extracted from copper smelting slag using chlorine roasting and magnetic separation techniques for the first time. The results showed that hydrogen could reduce the ferrous chloride on the surface of the pellet to environmentally friendly iron, followed by the complete reduction of the ferrous chloride inside the pellet, thus increasing the metallic iron content in the roasted ore. Finally, the concentrate with a TFe (total iron) mass fraction of 73.41 wt% and iron recovery of 86.50 % was obtained, and XRF, XRD, and XPS analysis showed that iron is mainly enriched in the concentrate, and calcium, silicon, aluminum, and other elements are mainly enriched in the tailing. The innovative addition of recyclable additives in the roasting process not only reduces the production cost but also plays an important role in the current total environmental protection and environmentally sustainable development. Analytical methods such as thermodynamic evaluation, evolutionary trends of key elemental compounds, and molecular simulation were used to fully characterize the complex chemical processes of the chlorination roasting process. This study provides theoretical strategies for the cleaning of CSS and facilitates the industrial implementation of technologies for efficient and economical extraction of iron from CSS.