Secondary Zinc Waste Sludge: Resource Material with Potential Application

The waste sludge generated during secondary zinc extraction process of an industry was studied for the recovery of electrolytic grade zinc and copper. The physical, chemical and mineralogical properties of the secondary zinc waste were studied in detail. Toxicity Characteristic Leaching Procedure (TCLP) test was carried out for the sample and concentrations of heavy metals present in the waste were estimated. The engineering properties of the samples prepared through high temperature fired route provided important information on the characteristics and composition of the waste. Different binders like fly ash and yellow clay were used in different formulations using Indian Standard sand to prepare the samples and to study the Solidification-Stabilisation (S/S) mechanism of the encapsulated waste mass. The leachability studies and engineering properties of the samples were evaluated to study the abatement of hazardous potential of waste and to explore better utilisation options for the secondary zinc waste sludge.