The Study Of Copper Removal By Extraction In The Nickel Electrolyte

Nickel is one of the most important strategic storage metals, it is widely used in the fields of aviation, chemical and electronic industry etc. In the process of the production of pure nickel, the copper ions as one of the most important impurities must be removed from the nickel electrolyte. Solvent extraction has the merits of recycle, pollution-free and big handing capacity, and it is one of the most important methods of copper removal.The analysis of copper by Square-wave Stripping Voltammetry was uesd in this study. The effect of nickel ions on the analysis of copper could be ignored when setting the electrical potential between -0.7 and 0V, and the linear relationship between the concentration of copper and peak current was obtained in different ranges of concentratins. Then the error rate below 3% was obtained through comparing the experimental results with the results obtained by X7 Mass Spectrograph.In the study of the extractant P507, the effects of different temperatures, surging speeds and times, concentrations of organic phase, phase ratios, pH values on copper extraction were studied. Then the optimum conditions were obtained: the concentration of original phase 15%, phase ratio 1:1, pH value 3.0, room temperature, surging speed 200rpm and surging time 5min. The extraction ratio and the stripping ratio under the optimum conditions were 68% and 84%, respectively. Meanwhile, the mechanism of extraction of P507 has been gotten, and the ratio of five-stage extraction was 86% in experiment and the ratio was 99% in theoretical arithmetic, it meant there were some error spans between the fact and the theory.The synergistic extraction system of the extractants P204 and TBP with kerosene as thinner was studied. The effects of different experimental conditions, such as pH values, phase ratios, concentrations of organic phase, the ratios between extractant and synergistic extractant on copper extraction have been studied. The orthogonal experiment was carried out with the most effective factors. The results shew that under the optimum conditions the single-stage extraction ratio and the stripping ratio were 66% and 77%, respectively. Comparing the extraction ratio with the ratio of the single extractant of P204 or TBP, the synergistic system did not have obvious synergistic effect; after five-stage extraction the concentration of copper dropped to 0.039g/L, which could satisfy the demand of production basically.