A liquid surfactant membrane process for separating U(VI) from Sulfuric acid media was investigated using N-alkylcaprolactam (B-s) as a carrier. The operating conditions, including the concentrations of the extractant and stripping agent and the volume ratios of the (W/O)/W emulsion were optimized for the U(VI) extraction, from the viewpoint of their effect on the kinetics and recovery efficiency as well as the stability of the (W/O) emulsion drops. It was found that the liquid membrane containing n-dodecane used as a solvent, ECA4360J as a surfactant and B-8 as a carrier is an effective membrane for extracting U(VI) from sulfuric acid, and the concentrations of B-8 should be within the range between 0.03 and 0.05 M for keeping the emulsion stability. At the same time, a two-stage counter-current operation was demonstrated and results showed that LSM process in two-stage operation is effective. (C) 2005 Published by Elsevier B.V.