Liang Ming, Hong Yan, Di Haokai, Yang Kun, Zhang Libo
State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization, Kunming University of Science and Technology, Kunming, Yunnan 650093, China.
Yunnan Provincial Key Laboratory of Intensification Metallurgy, Kunming, Yunnan 650093, China.
Langmuir. 2024 Jun 25;40(25):13167-13176. doi: 10.1021/acs.langmuir.4c01167. Epub 2024 Jun 11.
In the leaching process of secondary zinc oxide, there is a problem of germanium loss caused by the colloidal adsorption of germanium by iron hydroxide (Fe(OH)) formed by Fe hydrolysis. In response to this, this article elucidates the hydrolysis conditions of Fe and the adsorption mechanism of the Fe(OH) colloid on germanium through theoretical analysis and simulation of the adsorption process. The coexistence of Fe and HGeO requires high acidity conditions (pH < 1.53 at 25 °C). The adsorption of germanium by the Fe(OH) colloid is a spontaneous exothermic entropy reduction process, which conforms to a pseudo-second-order kinetic model and includes three stages: fast, slow, and equilibrium. In addition, the adsorption process can be fitted by the Langmuir isotherm adsorption model, mainly consisting of monolayer and chemical adsorption. The Fe(OH) colloid has a great adsorption capacity for germanium at 328 K, and the equilibrium adsorption capacity is 261.15 mg/g in 40 min. During leaching, the adsorption of germanium by Fe(OH) colloids can be inhibited by increasing the reaction temperature, controlling the pH value of the solution system, and suppressing the formation of Fe at the source. This study provides direction for how to suppress the adsorption of germanium by Fe(OH) colloids during the leaching process of secondary zinc oxide, which is of great significance for improving the germanium leaching efficiency and fully utilizing limited germanium resources.
