Several Imidazole Ionic Liquid Research On The Effects Of The Quality Of Electrolytic Copper

High purity copper is increasingly demanded with the development of social economy. Electrolytic refining process is a very good choice in order to obtain the relative purity copper. However, appropriate amount of additive is essential in the copper electrolyte to obtain high purity, bright, uniform, dense copper products. A combination additive of gelatin, thiourea, hydrochloric acid is used in domestic factories, Gelatin has instability in hot acidic electrolyte, it will decompose easily and have no effect; a higher concentration of thiourea accumulates easily in the electrolyte, resulting in the pollution of copper cathode. The scientists have’t stopped studying additives.Firstly,1-butyl-3-methylimidazolium hydrogen sulfate ionic liquid ([BMIm]HS04) was used in the electrolytic copper. The morphology observation of the copper which obtained from electrolyte containing [BMIm]HS04alone as an additive indicate that,when the concentration of [BMIm]HS04was30mg/L, the grain refinement effect was more obvious; The mixed additive of [BMIm]HSO4and gelatin has a negative influence in improving the quality of the cathode copper; Rose-red cathode copper product was obtained,when [BMIm]HSO4and thiourea as a mixed additive and their content between15mg/L-20mg/L, but it will pollute the cathode copper to some extent when the amount of thiourea is too large.Secondly, a range of different chain lengths, different alkyl-substituted imidazole chloride ionic liquid were studied as copper electrolytic refining additives. The results of the metallographic tests, scanning electron microscopy, roughness tests on part of the cathode copper showed that:These additives can obviously refine grains, uniform, make the surface grain even dense. And better cathode copper can be obtained when1-Helsinki-2,3-dimethyl-imidazolium chloride ion liquid ([OMMIm]Cl) was added into the electrolyte;Then cyclic voltammetry and Tafel tests were carried out in the electrolyte which containing imidazolium chloride ionic liquid, the result show that these imidazolium chloride ionic liquid have a stimulative effect on the reduction of copper ions; And then a mixture additive of [OMMIm]Cl and gelatin,[OMMIm]Cl and thiourea respectively for electrolytic refining were studied, the results showed that the combination of [OMMIm]Cl and gelatin is better for electrorefining; the stability of [OMMIm]Cl was tested from two aspects:the copper electrolytic refining process and electrochemical tests, and the result is that the ionic liquid [OMMIm]Cl has a relative strong stability in the hot acidic environment of62℃.