SEPARATION OF ZIRCONIUM(IV) FROM IMPURITIES WITH TRIBUTYLPHOSPHATE FOR DETERMINATION OF THEM BY ICP-MS

Abstract

    The investigation of the effects of extraction time, extractant concentration, diluents, acids andloading capacity of the solvent, cycles extraction on solvent extraction of zirconium (Zr) fromacid solutions with tributyl phosphate (TBP) in toluene as the extractant. With the extractionof 20.5 mg/mL Zr(IV), optimal conditions were: extraction medias was 8 to 12M HNO3,diluent was toluene, TBP concentration was 50% in toluene, extraction time was 1 hour,loading capacity of 50% TBP in toluene after 4 times the contact phases was 20.43 mg/mLZr(IV), stripping of metal from the loaded organic (LO) with different nitric concentrationsindicated (0.05 to 0.5M) HNO3 are the best, and (8 to 10M) HNO3 is the poorest strippingagent. Mc Cable-Thiele plot for the extraction of Zr(IV) from nitric acid indicated therequirement of 2 stages at organic phase/aqueous phase (O/A) volume ratio of 2/1 to extractthe 98.75% of Zr(IV).With 3 to 4 cycles extraction using 8M HNO3 (for extraction) and 10M HNO3 (for stripping),investigated higher 95% of almost impurities (35 impurities) can be separated and Zrremained in aqueous phase about 3 - 4 %. It was found that with the mentioned amount of Zr,effect of Zr on the determination of impurities, except Hf, Ti, Fe, Ga, Cd, V, Sc, As, Se by ICPMScan be negligible. This system extraction can be used in separation of the matrix Zr(IV)and determination of impurities in high purity zirconium (alloys, salts and oxides) by ICP-MS.

Keywords: Extraction, zirconium, acids, TBP, toluene, impurities, ICP-MS.