2024 Sari Ultrasound assisted leaching of zinc plant residue

Zinc plant residue (ZPR) contains significant amounts of valuable metal (Zn, Pb, Ag, etc.) compounds, as well as various heavy metals and harmful compounds that pollute the environment. Processing such residues allows for the recovery and reuse of valuable metals, which is crucial for sustainable resource management. This study investigated a two-stage leaching process of Zn, Pb, and Ag recovery from ZPR. The first stage of ultrasonic-assisted leaching of ZPR was applied to produce an industrial selective zinc acetate solution. Leaching experiments were carried out with an ultrasonic device in the presence of acetic acid, known as organic acid. Under optimum leaching conditions, the extraction of Zn and Fe metals was obtained as 76.13% and 1.32% Fe, respectively. According to the Brunauer–Emmett–Teller (BET) analysis results on the original sample and ultrasonic leaching residue (ULR), the BET surface area and micropore area increased. However, the mean adsorption pore width decreased. In the second stage, conventional sodium chloride leaching was applied to recover lead and silver from the remaining solid after the first stage. Under the optimum conditions in this stage, 80.12% of Pb and 96.2% of Ag were extracted. The presence of coordination between Zn2+/AcO− (acetate) and Pb2+/Cl− complexes in the leaching solution was revealed by Raman spectroscopy. Finally, according to the characterization analysis of the final leaching residue, it was determined that iron oxides and silicate species accumulated in the solid. In conclusion, a significant reduction in the rate of pollution and toxic metals in ZPR was noticed.