Stabilization of smelter contaminated soil using a sustainable steel-slag-based binder

Abstract

In this study, a series of tests are conducted to investigate the performance of monopotassium phosphate (MKP) activated basic oxygen furnace slag (BOFS) to stabilize a lead, zinc and cadmium-contaminated smelter industrial soil. Various mass ratios of MKP to BOFS are used to activate BOFS slag in order to explore the optimum MKP/BOFS ratio. Meanwhile, the influences of preparation and activation conditions of the BOFS slag are also investigated. The soil pH and leachability properties of the stabilized soil are used to evaluate the activation effectiveness of BOFS slag. The test results show that the leachate concentrations of Pb, Zn and Cd are significantly reduced with the addition of MKP activated BOFS and the optimum MKP/BOFS ratio is 2–4%. The mixing method has a remarkable influence on the immobilization effectiveness of heavy metals, and the activated BOFS obtained from wet mixing is found to possess superior performance. It is also found that the drying temperature has little influence on the immobilization effectiveness of heavy metals.