Separation Process and Behavior of Copper and Germanium in Acid Leaching Solution from Zinc Hydrometallurgy.

In the countercurrent leaching process of neutral leaching and acid leaching in traditional zinc hydrometallurgy process, a small part of copper and most of germanium in the acid leaching solution will precipitate into the leaching residue when the acid leaching solution returns to the neutral leaching process, resulting in low recovery of copper and failure of direct separation and enrichment of germanium. Focusing on the separation and enrichment of copper and germanium in acid leaching solution of zinc calcine, the separation behavior of copper and germanium in the process of directly copper replacement and germanium neutralization precipitation of acid leaching solution was studied. The experimental results show that higher amount of iron powder and lower pH value will cause coprecipitation of copper and germanium in the acid leaching solution. Under the conditions of the temperature of 70 °C, iron powder stoichiometric addition of 1.2, time of two hours, pH value of 1.5-2.0, and reaction time of 20 minutes, the precipitation rate of germanium and copper is 2.51% and 96.53% respectively, which realizes effective separation of copper and germanium in solution. The arsenic in solution is co-precipitate wth copper. The main phases in the cementation products are Cu₃As and Cu₂O, and the mass fraction of copper in replacement precipitate is 58.02%. Under the condition of H₂O₂ dosage of 5 mL/L, temperature of 70 °C, time of 2.5 hours, and end point pH value of 5.0-5.2, the content of copper, iron and germanium in the neutralization solution is 16.52, 1.39 and 0.43 mg/L, respectively, which meets the requirements of subsequent purification. The neutralization residue is enriched with 2 501.40 g/t of germanium, which can be used as raw material for recovery of germanium. [ABSTRACT FROM AUTHOR]