Extraction of Zn by Microemulsion

The microemulsion system of oleic acid/butanol/sodium carbonate solution was used to extract emtal ion Zn~(2+).The main experimental parameters, which influence extraction rate, such as the constitution of microemulsion, pH value in aqueous phase, R_(ew), stirring time, were studied. The experimental results show that the extraction rate of Zn~(2+) can reach 99.91%, and the concentration of Zn~(2+) can be reduced to 0.7 mg/L from its initial concentration of 500 mg/L under the condition of acid/butanol/sodium carbonate solution=5∶5∶4(volume ratio),R_(ew)=1∶7,stirring time of 6 minutes and pH values of 5.1~5.8. The microemulsion system does not swell in the process of extraction when the quantity of NaCl in the aqueous phase is 1.5 g/L. The oil phase can be recycled by changing the pH value to demulsify the microemulsion system and the recycling experiment demonstrates that the oil phase can be reused for five times, but with little change of extraction rate.