Comparison of solidification/stabilization of lead contaminated soil between magnesia-phosphate cement and ordinary portland cement under the same dosage

Magnesia-phosphate cement (MPC) and ordinary Portland cement (OPC) stabilization are both practical approaches to remediate soils contaminated with high levels of lead (Pb). The differences in the strength and stability of Pb-rich contaminated soil solidified and stabilized using MPC and OPC are examined in this study, and leaching mechanism of Pb in curing bodies under strong acid environment was analyzed. Soil spiked with different Pb contaminations are stabilized with cement contents of 10, 20, and 30% and then cured for 28 days. The soil samples are then subjected to a series of unconfined compressive strength (UCS) and leaching tests (Toxicity characteristic leaching procedure (TCLP) and semi-dynamic leaching tests) using an acetic acid leachant at pH of 2.88. The results showed that the UCS and pH of curing bodies with OPC were higher than MPC at the same content. While MPC presented a better effect than OPC in the stabilization of Pb, and the leaching mechanism of Pb in curing bodies treated by MPC and OPC presented dissolution firstly and then followed by diffusion. (c) 2015 American Institute of Chemical Engineers Environ Prog, 35: 88-94, 2016