Ultrasonic pretreatment-solvent extraction process for separating zinc from pickling waste liquid

Solvent extraction is the most important method for non-ferrous metals extraction and separation. In this work, solvent extraction of zinc from pickling waste liquid is investigated by using di(L-methyl heptyl) methyl phos-phate (P350) diluted in sulfonated kerosene. Introduction of ultrasonic enhanced reduction of Fe3+ in the pre-treatment stage of pickling waste liquid. The effect of ultrasonic time on the reduction process of Fe3+ is studied. Compared with traditional restoration, the required time for reduction is greatly shortened. The functional relationship of organic phase composition, concentration of extractant, phase contacts time and phase ratio function in single-stage extraction is studied. When concentration of extractant is 25 %, phase ratio is 4:1, the contact time is 15 min and the single-stage extraction efficiency of Zn2+ can reach 80.8 %. The extraction ef-ficiency of Zn2+ reaches 99 % through three-stage countercurrent recovery. When O/A is 1:2, 1.6 mol/L HCl is used as the stripping agent and the stripping efficiency of P350 can reach 90.4 %. In addition, extraction stoi-chiometry is determined by slope analysis and extraction mechanism is analyzed by FT-IR and mass spectrom-etry. Overall, this work provides a new solution in the extraction of zinc from pickling waste liquid.