The Recycling of Heavy-metal-containing Wastes: Mass Balances and Economical Estimations

As environmental legislation has become stricter, the treatment of heavy-metal-containing residues has gained importance. This study aims to develop an economic process for the simultaneous recovery of multiple valuable metals from zinc-containing residues, ultimately targeting high-quality zinc production and a nearly zero waste process. Utilizing mass and energy balances, the research examines four secondary raw materials: neutral leaching residue, Waelz kiln slag, dust from the secondary copper industry, and electric arc furnace dust from carbon steel production. Intensive investigations were conducted on the characterization of these materials, yielding crucial data on reduction and smelting temperatures, as well as slag basicity, which are fundamental for process optimization. The findings indicate that varying the properties and compositions of secondary raw materials significantly influences the efficiency and economics of the recovery process. These results not only enhance the understanding of the treatment of heavy-metal-containing wastes but also contribute to developing sustainable metallurgical practices in accordance with stricter environmental regulations.