Leachability of V and Cr from LD-Slag/Portland Cement stabilised sulphide soil

The objectives of this study were to improve the mechanical stability of a sulphide soil with additives of an industrial waste product (LD-Slag) and Portland Cement. The criterion of using LD-Slag was if it could be done in an environmentally proper way. Sequential Leaching Tests were performed on monolithic LD-Slag/Portland Cement stabilised sulphide soil samples in order to register the leachability and pollution potentials. Different pH and Eh conditions were established in these tests in order to control the leachability of Na, K, Ca and Mg, which are important during cementation processes inside as well as outside an inforced monolith, and the leachability of V, which is regarded as a pollutant. The contents of Cr and V of pure LD-Slag, monolithic samples and leachates were compared with Canadian and Finnish Maximum Containment Level standards. The investigation showed that acidic conditions will increase the leachability of V. An acidic environment will even change the physical properties of a monolith. However, acidic conditions are not likely to occur in an in-situ anaerobic sulphide soil.