Remediation of soils contaminated by lead-containing shotgun pellets

摘要

The use of mineral processing techniques to remediate shooting range soils contaminated by lead-containing shotgun pellets has been evaluated. Most of the lead in the soil sample is in the form of coarser pellets, which can be easily recovered mechanically by combining screening with a consecutive gravity concentration stage. The total recovery of lead into practically pure pellet product is 90percent in this process. The fine, altered part of the lead pellets, identified as a carbonaceous phase, is much more problematic. As this phase is more soluble and has a large specific surface area, it forms a particularly hazardous source of contamination for the environment. Complex-forming leaching and a consecutive precipitation by sulfide was used to recover the lead from this finer part with a recovery of about 96percent. A total lead recovery of 99.9percent can be reached by combining the mechanical and leaching processes.