Abstract: The process of separating Rb and K from mother liquid after extracting Cs was investigated by using t-BAMBP as extractant and sulfated kerosene as diluent.The effects of reaction time，concentration of t-BAMBP，extraction phase ratio， and other related factors on the separation of Rb and K were also investigated.The optimal conditions were as follows：t-BAMBP/sulfated kerosene system was 0.7 mol/L，extracting time was 5 min，extraction phase ratio was 3∶1；0.1 mol/L NaCl as washing liquor，washing phase ratio was 4∶1；0.5 mol/L HCl solution as stripping agent，phase ratio was 5∶1.After 5 stages countercurrent stripping，the stripping rate of Rb increased above 95.6%，with a higher separation coefficient of Rb/K and achieved the separation of rubidium and potassium.

Key words: rubidium, t-BAMBP/sulfated kerosene extraction system, extraction, back extraction