Assessment of Heavy Metal Leachability from Clay Soil Stabilized with Calcinated Iron Ore Tailings-Based Geopolymer

The stabilization of clay soil (CS) using iron ore tailing (IOT) offers a sustainable waste management and efficient circular economy. However, CS stabilization with IOT can lead to the leaching of heavy metals (HMs) into the environment. This study investigates the potential of geopolymerization as an alternative technique for mitigating HM leaching while stabilizing soil. The TCLP was used to extract leachate from samples of CS stabilized with IOT (S1), with calcinated IOT (CIOT; S2), and with CIOT-based geopolymer (GP; S3). The results specify that leaching concentration of HMs (identified using ICP-MS) decrease S1–S2 as follows: Ba from 1.0935 to 0.835 mg / L , Bi from 0.00019 to 0.00016 mg / L , Cd from 0.0174 to 0.00312 mg / L , Co from 0.0562 to 0.00894 mg / L , Cu from 0.06758 to 0.06205 mg / L , Mn from 2.0160 to 1.5216 mg / L , Pb from 0.0266 to 0.0263 mg / L , Sr from 2.363 to 1.641 mg / L , and Te from 0.00073 to 0.00062 mg / L . Except for Co, all the HMs are exceeding the permissible limits prescribed by USEPA, WHO, and BIS standards. However, the CS stabilized with CIOT-based GP sample (S3) exhibited a substantial reduction in HMs with a concentrations of 0.6586 mg / L (Ba), 0.00015 mg / L (Bi), 0.00204 mg / L (Cd), 2.55 E - 05 mg / L (Co), 0.0290 mg / L (Cu), 0.138 mg / L (Mn),