Department:
Catalysis & Inorganic Chemical Technology
Project manager(s):
Year:
2018
Financial supporter:
Iran National Science Foundation
| The application of zinc solvent extraction for solutions containing impurities such as iron, nickel, cadmium and rare earth elements is very important in lead and zinc mine industries to further purify electrolyte and increase its zinc content before zinc electrowinning. In the solvent extraction process, after loading metal ions in an organic extractant, the important stripping stage (metal ion transport from the organic phase to aqueous phase) needs to be optimized. This study investigated the effective factors on zinc solvent extraction by D2EHPA extractant in the presence of iron, nickel, cadmium ions and rare earth elements of lanthanum and cerium; then, the effective factors on the stripping process were optimized. According to the obtained results, the presence of complexing agents such as lactic acid and citric acid, pH of the aqueous solution, and extraction concentration as well as the use of ultrasonic waves for the mixing of organic and aqueous phases were effective factors in achieving an aqueous zinc solution with the lowest impurities. The chemical species of metals in aqueous solution at various pHs were studied using the Visual Minteq software. The amount of zinc extraction increased with the application of ultrasound power compared to normal mixing. This 20 % increase of zinc extraction was observed when applying ultrasound at a power of 30W. The ultrasonic application, in comparison to an increase in temperature up to 50 C, caused a greater increase in the amount of stripping of the metals being studied. The presence of acetic acid, similar to lactic acid, reduced the extraction of Fe and Ni. The amount of the extraction of Zn in the presence of acetic acid as a complexing agent was much higher than that in the presence of lactic acid. In the absence of complexing agents, the amount of Zn extraction was 37% which reached 68% and 56% in the presence of acetic acid and lactic acid, respectively. |