The emulsification extraction process (EEP) is a novel method for separating solutes from aqueous solution, and for its high extraction ratio, the EEP presents huge potential for extraction from dilute solution. In this paper, the EEP is successfully generated with mixing solutions containing aqueous and organic phases at high speed. The extraction of Mg2+ from ammonium dihydrogen phosphate (NH4H2PO4) solution is studied by using kerosene as a solvent, di(2-ethylhexyl)phosphoric acid (D2EHPA) as an extractant. To study the extraction ratio and advantages of the EEP process in the removal of Mg2+, various parameters - D2EHPA volume fraction, reaction temperature, phase volume ratio, initial pH of NH4H2PO4 solution, stirring speed, stirring time were studied and optimized. The results show that Mg2+ in NH4H2PO4 solution can be effectively removed by EEP process. An extraction ratio of more than 90.1% is attained at the optimized parameters and superior-grade NH4H2PO4 (MAP) can be obtained by two levels of extraction.
Key words: Emulsification extraction process, di(2-ethylhexyl)phosphoric acid, NH4H2PO4, Mg2+.