Remediation of soils contaminated by lead-and copper-containing rifle bullets

摘要

Mineral processing techniques were evaluated to see if they could be used to remediate rifle range soils. The soils studied originated from two Finnish rifle ranges, Viikinmaki and Utti, and were heavily contaminated by lead- and cooper-containing bullets and their disintegrated fine-grained weathering products. Most of the lead and copper in the soil samples is in the form of coarser particles, which can be easily recovered mechanically by combining wet sieving with consecutive gravity concentration stages. In this process, 83-85% of the total lead and 91-99% of the total copper can be recovered into a ca. 90% pure bullet product. The fine soil fraction contains 14-17% of the total lead, mainly as fine-grained carbonaceous weathering products of the bullets, and 1-3% of the total copper. Due to the higher solubility of the lead carbonates and the high surface area of these particles, they form a significant source of contamination for the environment. Complex-forming leaching was used to recover the lead and copper from the fine soil fractions with recoveries of 95-98%. By combining the mechanical and leaching processes, lead and copper recoveries in excess of 99.4% can be reached.