Simultaneous Immobilization of Copper (Cu), Nickel (Ni), and Lead (V) Using Steel Slag Fines

The simultaneously immobilization potential of dissolved Cu, Ni, and Pb in a packed column of freshly crushed steel slag fines (SSF) media was evaluated. The SSF media was characterized as USCS SP type soil with <5% passing the No. 200 (0.075 mm) sieve and the flow rates were on the order of a meter per day with a residence time on the order of 3.5 hours for a 25 cm long column containing approximately 5 kg of SSF media. The combined influent concentrations were in excess of 500 mg/L Cu and Ni, and 5,000 mg/L Pb to be consistent with concentrated waste streams and/or industrial processes. The influent pH of the multi-metal solution was on the order of 4.2; and the pH of the effluent for the test duration of 100 pore volume (PVs) never decreased below 12. Copper and nickel detection (0.05 mg/L) in the effluent was delayed for approximately 46 PV and the copper limit in drinking water (1 mg/L) was reached at 78 PV. The effluent concentrations of Pb exceeded 5 mg/L at approximately 38 PV which corresponded to an immobilization of Pb on the order of 50,000 mg/kg and 5,000 mg/kg each of Cu and Ni.