Abstract:
This research work was investigated leaching test methods of heavy metals from the solidified Zinc-Cyanide electroplating waste using Ordinary Portland Cement and Lignite Fly Ash as solidificationbinder. The electroplating sludge was used at 10 wt% and Lignite Fly Ash was used at 0, 10,20 and30 wt% throughout this work. TCLP results show that the concentration of Cr was not exceed thelimit specified by the USEPA. Although Zn and Fe were not specified by the USEPA, but they werepresent in the leachates at concentrations lower than 1 mg/L and 1.5 mgIL, respectively. The DLTresults show that under the mild leaching condition (initial pH of leachant was approximately 5-6),Fe was present in the leachates at higher concentration than Cr whereas the concentration of Zn waslower than the detection limit of ICP-AES. All three metals were present in the leachates at higherconcentration under severe leaching condition (initial pH of leachant was approximately 3). Forleaching test under controlled pH, the concentration of all three metals was highest when leachatepH was controlled at 4. Reduction in concentration of these three metals was observed whenleachate pH were increased. In addition, the concentration of these three metals in the leachatesextracted from the ground samples was higher compared to that extracted from the whole samples.