Characterization of Galvanic Sludges Waste Derived of the Metal Plating Industry from Cariri Region, Northeastern of Brazil

Abstract

In this study, galvanic sludge waste (GSW) was characterized in order to identify its chemical and structural properties, allowing indicate reuse, treatment and final disposal methods, and evaluate the environmental hazards. The characterization of the galvanic sludge sample originating from a surface treatment plant from galvanic industries of semi-jewels in the Cariri region, NE of Brazil was performed. The chemical characterization of the samples by flame atomic absorption spectroscopy (FAAS) and X-Ray Fluorescence (XRF) showed that Zn and Cu are the predominant elements. However, elements like Ni, Cd, Mn, Fe, Cr and Co are present as a minority or as trace constituents. The concentrations of residues were higher, except Ni, in the LM industry (27 g Zn.kg -1, 194 g Cu.kg -1, 8 g Fe.kg-1, 538 mg Cd.kg -1, 227 mg Ni.kg -1, 73.5 mg Cr.kg1, 14 mg Co.kg-1) in relation to LJ (11 g Zn.kg-1, 3 g Fe.kg-1, 102 g Cu.kg-1, 2 g Cd.kg-1, 141 mg Ni.kg-1, 11 mg Co.kg-1), denoting that there is no uniform standard in the treatment process of the effluent from baths for Metal deposition. According to the standard procedure (Brazilian norm NBR10004/04) the elements Cd and Cr are the main constituents responsible for the classification of the residues as hazardous. The X-ray diffractogram of the dried galvanic sludge only revealed the presence of BaSO4 and CuO as crystalline phases, a result which agrees with the results from FT-IR. The results point to an attractive way of valorizing GSW avoiding the negative impact associated with its disposal in landfills.