Solvent Extraction of Hafnium( Iv) With 3-Hydr0xy-2-Methyl-1-Phenyl-4-Pyridone

The extraction of hafnium(IV ) from aqueous hydrochloric, sulphuric and perchloric acid solutions with 3-hydroxy-2-methyl--1-phenyl-4-pyridone(HX) dissolved in chloroform is described. Perchlorate and thiocyanate ions show a synergistic effect on hafnium extraction with HX. Hafnium can be quantitatively extracted with HX from more acidic solutions and with less excess of HX if the extraction is carried out from a hydrochloric, sulphuric or perchloric acid solution containing an excess of perchlorate or thiocyanate ions. A mixed Hf-NCS-HX complex is more stable than a mixed Hf-ClO4-HX complex and thiocyanate ions show a stronger synergistic effect than perchlorate ions.