用反渗透技术回收镀镍漂洗水

Recovery of Nickel-plating Rinsing Water with Reverse Osmosis Technology

利用反渗透技术将镀镍漂洗水浓缩分离,浓缩液中ρ(Ni2+)达到20g/L左右,浓缩液补加到镀镍槽中,透过液在镀镍漂洗槽中循环使用,实现了镀镍废水的零排放。向镀镍槽中加入硫酸钾,提高镀液的导电性能,同时降低镀液中氯化镍的质量浓度,使镀镍过程中阳极溶解速度和阴极沉积速度相接近。镀件在镀镍前和镀镍后都经过回收槽漂洗,使回收槽中镍离子的质量浓度保持不变,大约是镀镍槽中镍离子质量浓度的一半。采用这些措施后,可实现反渗透浓缩液的完全回收利用。

Nickel-plating rinsing water was concentrated with the reverse osmosis technology, where the mass concentration of nickel ion could increase to 20 g/L. The concentrated liquor was added to the nickel- plating bath and the infiltrated water was used circularly in rinsing bath. Consequently, no nickel- plating wastewater was discharged Potassium sulfate was added to the nickel-plating solution to improve its electro-conductivity, and the concentration of nickel chloride was controlled at a low level, which make the dissolving rate of the anode to be close to the cathode sedimentation rate during electroplating. Workpieces were rinsed in the recovery bath before nickel-plating and after nickel-plating, with the result that, the concentration of nickel ion in the recovery bath was unchanged on the whole, and it was approximately half the concentration of nickel ion in the nickel-plating bath. By using these techniques, the concentrated liquor can be entirely added to the nickel-plating bath.