Research on the mechanism of lead sulfate adsorption of germanium and ultrasonic inhibition during the leaching process of zinc oxide dust containing germanium

Abstract

In response to the problem of germanium adsorption loss caused by lead sulfate adsorption during the leaching process of zinc oxide dust containing germanium, this article simulates and identifies the mechanism of lead sulfate adsorbing germanium, and innovatively introduces ultrasonic to suppress the adsorption of germanium by lead sulfate. Research has shown that the adsorption process of lead sulfate on germanium conforms to the pseudo-second-order kinetic adsorption model. The diffusion process of germanium adsorbed on lead sulfate particles can be divided into three stages: fast, slow, and equilibrium. The adsorption of germanium by lead sulfate conforms to the Langmuir isotherm adsorption model, and is mainly monolayer adsorption and chemical adsorption. In addition, the adsorption at 298–328 K is a spontaneous, endothermic, and entropy increasing process, while at 328–358 K it is a spontaneous, exothermic, and entropy decreasing process. At the same time, it was also found that low temperature, high temperature, and high-power ultrasonic can inhibit the adsorption process. Under ultrasound conditions of 358 K and 60.0 W, the equilibrium adsorption capacity of lead sulfate on germanium was 7.48 mg/g, and the germanium adsorption efficiency was 18.09%, which was 48.01% and 6.73% lower than conventional methods, respectively. Moreover, the leaching efficiency of germanium in actual dust leaching is increased by 6.17%, reaching 89.64%, verifying the simulation results. The new process of ultrasonic suppression of germanium adsorption by lead sulfate in the leaching process of zinc oxide dust containing germanium established in this article can effectively achieve efficient recovery of germanium from zinc oxide dust, providing a process and theoretical basis for the sustainable development of the world's germanium industry, and is of great significance for ensuring the safety of the world's important strategic resource supply chain.