Separation of Group IVB from Liquid Media
The Group IVB elements of titanium, zirconium, and hafnium readily lose their four outer shell electrons to form +4 ions in solution. The group IVB elements are found as oxides, halides, sulfates, and mixed complexes. Due to their nearly identical atomic radii, Zr and Hf are virtually identical from a separation standpoint.
Titanium, zirconium, and hafnium are present as cations in acid, so a strong acid cation resin like AmberSep™ G26 H Resin is the separation media of choice. In dilute hydrochloric acid, Ti, Zr, and Hf have a high affinity for a strong acid cation resin. The affinity diminishes as the concentration increases from 4M to 8M HCl, but then the affinity increases again as acid concentration increases above 8M.
In perchloric acid, a strong acid cation resin has an even higher affinity for these cations.
In HF and HCl, these elements also form anions that can be captured on a strong base anion exchange resin like AmberSep™ 21K XLT Resin1.
Often these metals are separated from other closely associated metals so resins with the maximum number of theoretical plates are needed. Strong acid cation fine mesh resins are proposed for this separation, such as AmberChrom™ 50WX8 100-200 Resin or AmberChrom™ 50WX4 100-200 Resin.