镍白铜废料中铜的低电流密度电解回收

Recovery of Copper from Cupronickel Alloy Waste by Low Current Density Electrolysis

对镍白铜合金废料进行直接低电流密度电解回收,考察了电解液温度、电流密度、明胶浓度对阴极铜纯度和表面质量的影响.结果表明,一定范围内电解液温度升高阴极过电势降低,铜离子扩散速度加快,阴极表面铜离子缺乏程度缓和,阴极铜结晶细化;在Cu^(2+)浓度45 g/L、H_2SO_4浓度180 g/L、电流密度100 A/m2的条件下,48 h内电流密度小于极限电流密度的0.1倍,电解区域处于塔费尔控制区,阴极铜产品平整光滑;控制明胶浓度40 mg/L、电解液温度60℃和电流密度100 A/m2时,镍白铜废料直接电解所得阴极铜纯度达99.98%,表面平整韧性良好,阳极残极率为17%~19%,铜回收率达98.6%.

Recovery of copper from cupronickel alloy scraps was carried out with direct low current density electrolysis method. The effects of electrolyte temperature, current density and gelatin concentration on the cathode copper quality were examined. The results show that the diffusion rate of copper ion can be accelerated while the electrolyte temperature rises in a certain range, which will ease the lacking degree of copper ion on the surface of cathode and fine the crystallization of cathode copper, though the cathode over-potential deceases. When the Cu^2＋ and H2SO4 concentrations are of 45 g/L and 180 g/L, the current density of 100 A/m^2 is less than 0.1 times of limiting current density in 48 h, the electrolysis process is in Tafel area, smooth cathode copper product can be obtained. Under the conditions of electrolyte temperature 60 ℃, cathode current density 100 A/m^2 and gelatin concentration 40 mg/L, the purity of copper cathode of 99.98% can be obtained, while the residual anode rate is 17%～19% and copper recovery rate 98.6%.