Extraction and separation of zirconium from hafnium using a new solvent microextraction technique

A simple method based on the dispersive liquid-liquid microextraction and a solidification of floating organic drop followed by an inductively coupled plasma-optical emission spectrometry (ICP-OES) was developed for the extraction and separation of zirconium from hafnium. In this extraction method, an appropriate mixture of acetone (disperser solvent) and 1-undecanol (extraction solvent) was injected rapidly, into the sample solution containing 2.0 mol L-1 nitric acid and metal ions in their complex form with cyanex272 and a cloudy solution was formed. After centrifugation, the test tube was cooled by inserting it into an ice bath for 5 min. The solidified 1-undecanol on the top of the solution was transferred into suitable vial and immediately melted, then, 100.0 mu L of it was dissolved in 100.0 mu L of 1-propanol and finally, was injected into an ICP-OES by a flow injection system for analysis. Some effective parameters on the extraction and separation of zirconium and hafnium such as type of extraction and disperser solvents and their volumes, type and concentration of ligands, and the type and concentration of acids have been evaluated and optimized. Under the optimum conditions, the selectivity factor of about 13 was obtained.