The extraction and separation of heavy rare earths from ion-adsorbed rare earth deposit using CYANEX (R) 572 were first investigated. The comparison of selectivities for heavy rare earth ions reveals that CYANEX (R) 572 is more effective than common industrial extractant P507, especially for the enrichments of Tm, Yb, and Lu. Considering the lower acid requirement and higher stripping efficiency of CYANEX (R) 572, the novel extractant CYANEX 572 has revealed industrial application values for the separation of heavy rare earths from ion-adsorbed deposit. (C) 2015 Elsevier B.V. All rights reserved.