F. Hurst
Mar 1, 1983
Citations
1
Influential Citations
28
Citations
Journal
Hydrometallurgy
Abstract
Abstract High-resolution, pressurized ion exchange has been used successfully to study and separate hafnium sulfate and zirconium sulfate complexes from Dowex 50W-X8 (15–25 μm) resin by chromatographic elution with sulfuric acid solutions. Techniques were developed to continuously monitor the column effluents for zirconium and hafnium by reaction with fluorometric and colorimetric reagents. Since neither reagent was specific for either metal ion, peak patterns were initially identified by using the stable isotopes 90 Zr and 180 Hf as “fingerprints” of their elution position. Distribution ratios for both zirconium and hafnium decrease as the inverse fourth power of the sulfuric acid concentration below 1.5 N and as the inverse second power at higher acid concentration. The hafnium-to-zirconium separation factor is approximately constant (≈8) over the 0.5–3 N range. Under certain conditions, an unseparated fraction was observed that was not retained by the resin. The amount of this fraction, which is thought to be a polymeric hydrolysis product, appears to be a function of metal and sulfuric acid concentrations. Conditions are being sought that will give the highest zirconium concentration and the lowest acid concentration that can be used as a feed material for commercial scale-up in the continuous annular chromatographic (CAC) unit without formation of the polymer.