Kinetics and mechanism of ultrasonic-enhanced mixed acid leaching of zinc from zinc-bearing dust

With the increasing depletion of zinc sulfide mineral resources, the shortage of raw materials has become a key factor restricting the sustainable development of China's zinc industry. The large amount of zinc-bearing dust generated during smelting, which mainly contains valuable metals such as zinc and iron, will undoubtedly become a vital zinc resource. Consequently, the development of a more energy and sustainably-efficient technique for the integrated treatment of dust containing zinc is required. In the study, the behavior and kinetics of mixed sulfuric and ascorbic acid leaching in an ultrasonic environment to extract zinc from zinc-bearing dust were investigated. The findings showed that with the right parameters—an ultrasonic power of 600W, an ascorbic acid concentration of 0.08mol/L, a sulfuric acid concentration of 2mol/L, a liquid-solid ratio of 7mL/g, 90℃ leaching temperature, and 30min leaching duration—the zinc leaching efficiency could reach 98.96%. Kinetic analysis showed that the ultrasound-enhanced mixed acid leaching process and mixed acid leaching process were controlled by product layer diffusion and interfacial reaction. The ultrasound decreases the activation energy from 35.13 to 27.54kJ/mol. In addition, the characterization and analysis demonstrated that ascorbic acid intervention facilitated the dissolution of ZnFe2O4, which in turn increased the leaching impact of zinc, and ultrasonic waves fragmented the agglomerated mineral particles. These findings provide a theoretical framework for efficient and economical resource recovery from zinc-bearing dust in the steel industry.