Experimental study on solidification/stabilization of heavy metal lead and chromium sludge solidified by cement-based materials

To explore the strength change law and solidification mechanism of cement solidified heavy metal lead chromium contaminated soil, ordinary Portland (OPC) magnesium phosphate (MPC) were used for solidification/stabilization treatment. Through unconfined compressive (UCS) test, scanning electron microscopy (SEM) leaching toxicity microscopic characteristics type, content, ion concentration, age their influence on soil obtained. The UCS test shows that increases with content age. When OPC MPC to solidify was greater than MPC, when curing 28 days, 20% satisfied landfill requirements. showed after by ions in solution conforms national limit. For concentration less or equal 5000mg/kg, which conform limit standard. 10000mg/kg, exceeded Therefore, is more easily stabilized soil. Microscopic tests show solidified/stabilized through hydration products, namely, ettringite amorphous cementing materials. obtained reaction oxide ammonium dihydrogen form struvite, are encapsulated lattice achieve solidification/stabilization.