In the magnetically assisted chemical separation (MACS) process, ferromagnetic nanoparticles modified by solvent extractant are used to separate hafnium from zirconium. The contaminant-loaded nanoparticles are recovered using a magnetic field. The contaminants attached to the magnetic nanoparticles are subsequently removed using a small volume of snipping agent. In this study, tributylphosphate (TBP) modified magnetic nanoparticles with particle size of 10 nm were evaluated for the extraction and separation of hafnium from zirconium. Laboratory scale investigations were carried out on the effects of type and concentration of acid, and also concentration of Hf and Zr ions on the efficiency of extraction and separation stages. It was found that 4 M hydrochloric acid, 10 ppm Zr and 7.5 ppm Hf ions gave the best results with SF = 1.4 and 1.5 for the extraction and stripping stages, respectively. (c) 2014 Elsevier B.V. All rights reserved.