用双（２，４，４－三甲基戊基）膦酸－Ｓｐａｎ８０－甲苯乳状液膜研究了稀土离子的迁移行为。当膜相含１０ｘ１０￣（－３）～３．０ｘ１０￣（－３）ｍｏｌ／Ｌ双（２，４，４－三甲基戊基）膦酸和２％～４％（Ｗ／Ｖ）Ｓｐａｎ８０，内相含０．５０～２．０ｍｏｌ／ＬＨＣｌ，外相的ｐＨ为３．５～５０时，所有稀土离子都能快速并完全迁移。根据各稀土离子在此乳状液膜体系中迁移性质的差别，控制外相酸度，试验了稀土离子相互之间的分离情况。试验表明，用此乳状液膜体系分离稀土离子有良好的应用前景． The migration behavior of rare earth ions was investigated by using bis (2,4,4-trimethylpentyl) phosphonic acid-Span80-toluene emulsion membrane. When the membrane phase contains 10 × 10 -3 -3.0 × 10 -3 mol / L Bis (2,4,4-trimethylpentyl) phosphonic acid and 2% -4% (W / V) Span 80 , The inner phase contains 0.50 ~ 2.0mol / LHCl, the pH of the outer phase is 3.5 ~ 50, all rare earth ions can quickly and completely migrate. According to the difference of migration properties of the rare earth ions in the emulsion liquid membrane system, the acidity of the outer phase is controlled and the separation of the rare earth ions from each other is tested. Experiments show that the use of this emulsion membrane separation of rare earth ions have a good prospect.