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The manufacture of fine phosphates such as sodium dihydrogen phosphate (NaH2PO4) from wet-process phosphoric acid (WPA) is gradually paid attention to in recent years.However,there are some undesirable impurities (Fe3+,Al3+,Mg2+) in WPA,which will degrade the quality of sodium dihydrogen phosphate (NaH2PO4) products.There is still some Mg2+ in neutralized NaH2PO4 solution which can cause formation of troublesome water-insoluble substance in the concentration and crystallization process.The main ingredients of water-insoluble substance are magnesium-containing phosphate.Therefore,before the neutralized NaH2PO4 solution is concentrated,the Mg2+ should be removed.The colloidal liquid aphrons (CLAs) is a new method for separating solutes from aqueous solution,and for its high extraction ratio,the CLAs presents huge potential for the extraction from dilute solution.In present paper,colloidal liquid aphrons are successfully generated using kerosene as diluent,di(2-ethylhexyl)phosphoric acid (D2EHPA) as extractant,sodium dodecyl benzene sulphate (SDBS) as surfactant in aqueous phase and polyoxyethylene sorbitol anhydride monolaurate(Tween-20)in oil phase.The extraction of Mg2+ from neutralized NaH2PO4 solution is studied and optimized with CLAs.The results show that Mg2+ in NaH2PO4 solution can be effectively removed and superior-grade NaH2PO4 can be obtained by three levels of extraction by CLAs.