Integrated valorisation of a solid impurity stream in copper production: recovery and sustainability in metal extraction

The sustainable recovery of critical and added-value metals from industrial by-products is essential for circular economy strategies in metallurgical industries. This study presents an integrated approach for the speciation and selective recovery of copper (Cu), zinc (Zn), bismuth (Bi), iron (Fe), cadmium (Cd), bismuth (Bi), and lead (Pb) from electrostatic precipitator (ESP) converter dust generated in a Cu smelter, while separating arsenic (As) and tin (Sn).The ESP dust is composed of fine metal-sulphate particles with concentrations of Cu (16.4 wt%), Zn (14.4 wt%), Bi (1.51 wt%), Pb (12.2 wt%), Fe (1.33 wt%), and Cd (0.54 wt%). X-ray diffraction identified crystalline phases such as gunnite and anglesite, while thermogravimetric analysis highlighted distinct thermal decomposition pathways of metal-bearing species. A mass fractionation approach, integrated with a hydrometallurgical strategy involving ion exchange, electrowinning, and selective precipitation, enabled efficient metal recovery ranging from 84 % to 99 %, while ensuring effective separation of As and Sn.