Research on extraction of zinc from spent pickling solution using Aliquat 336

Zinc and iron were separated from the spent pickling solution by extraction with methyl trioctyl ammonium chloride (Aliquat 336). The purpose of the extraction experiment is to determine a variety of parameters (e.g. addition of octanol, contact time, phase ratio, [H+] concentration and Aliquat 336 concentration). Under optimal extraction conditions, the zinc extraction in one stage was above 92.4% and the separation coefficient beta(Zn/Fe) could reach 273 with initial zinc concentration 17.6 g/L, iron concentration 141.1 g/L and [H+]= 1.4 M. The zinc extraction mechanism was analyzed FT-IR spectroscopy and slope method. Zn(II) after extracting was comparative studied using different stripping agents. Recycling tests were also carried out, indicating that the extractant had a stable extraction performance, retaining 91.2% extraction efficiency of fresh extractant after 5 cycles.