Determination of zirconium in aluminium alloy by polarography
CHEN Wen
Institute of Material & Chemistry & Chemical Engineering, Chengdu University of Technology； Mineral Resources Chemistry Key Laboratory of Sichuan Higher Education Institutions ，Chengdu 610059, China
Abstract：On the basis of the property whose zirconium （Ⅳ） could form non-electrochemical active complex with salicyl fluorone （SAF） in hydrochloric acid medium, a new indirect determination method of zirconium by measuring the reducing peak current of SAF was established. The optimal base solution of this method was as follows: 0.24 mol/L hydrochloric acid, 8.0×10-5 mol / L SAF ethanol solution and 2.4 mg/L polyethylene glycol-20000 solution. Zr（Ⅳ） showed a sharp polarographic peak near -0.68 V （vs.SCE）. The peak current was linear to the concentration of Zr（Ⅳ） in the range of 0-840 μg /L, and the detection limit was 0.004 2 μg /L. This method was combined with the sample preparation by microwave digestion, and applied to the determination of zirconium in aluminium zirconium alloy standard sample. The results were consistent with the certified values. The polarographic behaviour of zirconium was studied by single scanning polarography. It proved that the electrode reactant was SAF, and the polarographic wave was irreversible absorptive reducing wave. The proposed method was applicable for the determination of zirconium （≤10 %） in aluminium zirconium alloy.
