Long-term leaching assessment of constituent elements from Linz–Donawitz slag of major steel industries in India

Abstract

Continuous long-term open column (> 1 year, during July 2014–July 2015) percolation leaching experiments were undertaken to assess leachability of important constituent elements from Linz–Donawitz slag of Rourkela, Bokaro and Tata steel plants. Leachates were continuously collected at an interval of 3–5 days from open column during 110 cycles of percolation leaching test and analysed for As, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Se, V and Zn concentration by inductively coupled plasma optical emission spectrometry. Leachate concentration of different elements showed remarkable variation in terms of leachability from different slag samples. Linz–Donawitz slags cumulative concentration of the elements in the leachate (µg/kg) range showed Mn (16.13–57.73) > Fe (38.36–54.43) > As (8.06–19.66) > Cu (7.83–10.66) > Cr (5.2–6.53) > Ni (5.2–6.16) > Zn (BDL—5.76) > Se (BDL—5) > Co (BDL—3.66) decreasing trend. Among Linz–Donawitz slags, Cr, Ni, Se and Zn leachate concentrations were relatively higher for Tata, whereas As, Co and Fe were higher for Bokaro. Leachate concentration of Cd, V and Pb was below detection limit in all slag samples from the steel plants. During initial period of leaching experiments, concentration of many elements (As, Cu, Fe and Mn) showed increasing trend, which reaches a plateau afterwards. The experimental results estimate low cumulative leachate content of different elements from Linz–Donawitz slag and therefore has prospect for bulk utilization for reclamation of degraded land, mine void filling, road construction etc.