METHOD OF EXTRACTION SEPARATION AND CONCENTRATION OF ZIRCONIUM AND HAFNIUM Russian patent published in 2002 - IPC

FIELD: hydrometallurgy of nonferrous metals. SUBSTANCE: invention relates to technology of preparation of nuclear-pure zirconium, particularly to separation of zirconium from hafnium during the processing of nitric acid- based hafnium-containing zirconium solutions. Method involves extraction of main part of zirconium from initial solution by recycle extractant containing tributyl phosphate. Principal zirconium extract stream is washed with aqueous solution to remove hafnium impurity and zirconium is then reextracted from principal zirconium extract stream. The total zirconium-free extractant stream is regenerated, acidified with nitric acid and returned into process as recycle extractant in three separated streams. Hafnium-free concentrated zirconium reextract is divided into two streams, one of them is withdrawn from the process and the other is used to wash principal zirconium extract stream to remove hafnium impurity. Resulting zirconium/hafnium aqueous solution is combined with initial zirconium/hafnium solution. Combined aqueous stream, after extraction of the main part of zirconium, is evaporated and still residue is used to recover hafnium and to additionally recover zirconium with a separate stream of recycle extractant, after which thus treated residue is withdrawn from the process. Hafnium/zirconium extract thus obtained is subjected to re-extraction of hafnium with nitric acid solution. Hafnium reextract is freed from zirconium with separate stream of recycle extractant and withdrawn from the process. Zirconium-containing organic washing stream is combined with hafnium/zirconium extract intended for hafnium re-extraction, after which resulting organic stream is added to principal stream of zirconium extract in operation wherein major part of zirconium is extracted. EFFECT: increased degree of purification of the two metals (by 80 times for zirconium and by 70 times for hafnium) and degree of their recovery and enabled preparation of concentrated zirconium and hafnium solution. 8 cl, 3 dwg, 4 tbl, 2 ex