| Impurity ions in zinc plant electrolyte will be accumulated and affect electrodeposits in the process of extracting zinc. Especially, copper, cadmium, cobalt and nickel could be reduced in cathode and form micro current with zinc, which will result in the having deposited zinc solved again. So it was necessary to determine these ions in the refining of zinc. Now, there were some report using polarograph method to determine these ions, but dropping mercury electrode which was used in the method was one of contaminations, so it was used less and less now. Voltammetry, glassy carbon electrode was working electrode, was used in this paper and realized the determination of copper, cobalt and nickel at the same time. The detail work:(1) Zincon and diacetyldioxime was used to form complex with copper, cobalt and nickel respectively. These complexes were easy to adsorb on glassy carbon electrode, which realize these ions determinated in a tiny amount. We also found in the presence of a mass of zinc, copper form complex only with zincon, while cobalt and nickel form complex only with diacetyldioxime, besides, the three peaks were departed with each other, which realize these ions determined very well.(2) We also focus on improving the reproducibility of glassy electrode. In the system of acid, alkali or salt, we discussed the effect of constant potential method and cyclic voltammetry method were used to activate glassy carbon electrode. We also found a method to remove adsorbate on the electrode after each scanning, which made the scanning curve coincide with the last time.(3) Chemically modified method was also employed to determinate metal ions. Diacetyldioxime was modified on glassy carbon electrode, which realized the determination of cobalt and nickel very well.(4) A easy and saving time method of preparation nano-alumina polishing powder was found in the paper. The product could be used to polish glassy carbon electrode which made it having a high sensitivity. |
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