SEPARATION OF TITANIUM FROM TANTALUM, NIOBIUM, AND TUNGSTEN BY CATION-EXCHANGE CHROMATOGRAPHY IN TARTARIC HYDROCHLORIC-ACID MIXTURES

Trace and larger amounts of titanium can be retained on a column of AG 50W-X8 cation exchange resin (100-200 mesh particle size) from a solut ion containing 0,25 mol dm-3 tartaric acid, 0,15 mol dm-3 hydrochloric acid, and 0,15% hydrogen peroxide, while tantalum, niobium, and tungs ten pass through the column. Separation factors are larger than 100 an d the separations are sharp and quantitative. Only microgram amounts o f tantalum were found in the titanium fraction when 100 mg was present originally. An amount of 5 mug of titanium was separated from 500 mg of tantalum and determined by direct current plasma emission spectrome try (DCP) as 4,9 mug with a coefficient of variation of 4%. For 100 mu g of titanium, this improved to 1%. A typical elution curve for the se paration of the Ta-Ti pair, results for the separation of synthetic mi xtures of titanium and one other element, and the determination of tit anium in three actual samples are presented.