槽边循环电解法回收电镀废水中Ni的研究

Reseach on Recovery of Nickel in Electroplating Waste Water Using Slot Cycle Electrolysis

对槽边循环电解法回收电镀废水中Ni进行了分阶段实验研究,包括小型试验、扩大试验以及系统扩大试验。试验结果表明,适合工业生产中使用的操作条件如下:Ni离子浓度可在0.5～2.5g/L变化,电流密度40～80 A/m2,槽电压3～6 V,pH=4.5～5.5;当Ni离子浓度保持在1.0～2.5g/L,若连续操作电流密度采用100～150 A/m2,则电流效率仍大于40%;若从高浓度操作到低浓度,每次回收到0.5 g/L,电流密度应取40～80 A/m2,操作10次后,可回收到使浓度小于0.1 g/L,弃掉,则回收槽的回收率大于99%;由3类不同规模试验的对比中可以看出,在相同条件下,电流效率几乎相等。研究表明,采用槽边循环电解法回收电镀废水中的Ni是完全可行的,且可保证较高回收效率。

Recovery of nickel in electroplating waste water using slot cycle electrolysis has been investigated by experimentation, including pilot test, extended pilot test, and system expansion. The main results indicated the appropriate conditions of the industrial production ： nickel ion concentration 0.5 - 2.5 g/L, current density 40 - 80 A/m^2 , voltage of the slot cycle 3 - 6 V, pH = 4.5 - 5.5. When the concentration of nickel ions remains at 1.0 - 2.5 g/L, the current efficien- cy is still greater than 40% if the current density adopting 100 - 150 A/m2 continuously; if the operation is from high concentration to low concentration and 0.5 g/L of each recycling, the current density should take from 40 to 80 A/m^2. The concentration recovered is less than 0. 1 g/L 10 times later. Discard it and the recovery rate of nickel would be more than 99%. By a comparison of three tests of different scales under the same conditions, it can be found that the current efficiency is almost equal. Using edge cycle of electrolysis to recover nickel in electroplating waste water is entirely feasible, and this method can ensure a high rate of recovery.