Study on the Treatment of Electroplating Sludge with Electro Technology

摘要

The electroplating sludge generated from electroplating industry is one of typical hazardous wastes containing high concentrations of heavy metals as Cu, Ni, Zn and Cr. Thus must be safely treated and disposed. According to the electrokinetic technology used in soil remediation and the limitations of other approaches in the treatment of electroplating sludge, the feasibility of the electrokinetic remediation in the treatment of the electroplating sludge was tested in a lab-scale experiment with practical sludge sampled at electroplating plant. To analyze the effect of applied voltage on the electrokinetic removal of the Cu, Cr and Zn from the sampled sludge,the experiments were operated for 36 hours and a series of voltage were applied. The results indicated that the removal efficiencies were low and increase with the increase of applied voltage. Removal efficiencies of Zn reach up to 4.7%, 5.4% and 14.1% respectively under the voltage of 1 V/cm, 1.5 V/cm and 1.8 V/cm. Attempt to improve the removal efficiency, two methods of controlling pH of the sludge during the process of the electrokinetic remediation were amended---ion selective membrane and sludge acidification, but the effect of these enhancement process was not obvious, the Cu concentration in anode and cathode apartment were 1.66mg/L and 0.115mg/L under acidification condition, comparing 1352.7mg/L and 0.014mg/L under membrane condition, respectively. Another method (acid-electrowinning) was also tested which showed a promising result to remove and recover heavy metals ,which covered 15.209g Cu plate and 14.514g Cu powder under 3 voltage and the Cu concentration of acid leaching solution decreased from 14964mg/L to 246 mg/L.