Extraction of rare earths from leach aqueous solution by conventional chemical precipitation brings severe amino-nitrogen pollution. In this work, a novel method was developed by organic hollow sphere to extract and enrich Er(III), a model middle-heavy rare earth ion, from diluent aqueous solution. The organic hollow sphere is a core-shell structure, in which the core is composed of gas phase and the shell is a thin layer of organic extractant. The effects of flow rates of gas phase and/or organic extractant on Er(III) extraction rate were investigated. The results demonstrated that the flow rate of gas phase played more important role than that of organic extractant in the extraction rate of Er(III). Accompanied by the achievement of a large volume ratio (1000:1) of aqueous solution to organic extractant, the enrichment ratio (100) of the rare-earth ions could reach a significant level, which is much higher than that by conventional methods. The lower flow rate of organic extractant is more beneficial to Er(III) enrichment. It demonstrates that the newly developed extraction technique in this work is promising, and as a result the development of organic hollow sphere extraction process for the recovery of REs is straightforwardly envisaged. (C) 2018 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.