Pilot-Scale Decontamination of Small-Arms Shooting Range Soil Polluted with Copper, Lead, Antimony, and Zinc by Acid and Saline Leaching

摘要

The objective of this study was to evaluate at the pilot scale the performance of a chemical leaching process for Pb, Cu, Sb, and Zn removal from a fine fraction (<125 mu m) of soil at two Canadian small-arms shooting ranges (SASR; Batoche: 418 mg Cu/kg, 5,006 mg Pb/kg, 168 mg Sb/kg, and 96 mg Zn/kg; Normandie: 1,015 mg Cu/kg, 6,024 mg Pb= kg, 305 mg Sb/kg, and 177 mg Zn/kg). A comparison of different leaching reagents revealed that the use of H(2)SO(4)d 0.125M + NaCl (4 M) is a very promising option from an economic point of view to solubilize metallic pollutants from highly polluted soils. The results showed that chemical treatment, including three successive acid-leaching steps (0.125MH(2)SO(4) + 4MNaCl, PD = 10%, t = 1h, T = 20 degrees C) followed by one rinsing step using water [ pulp density (PD) = 10%, time dt = 15 min, temperature dT = 20 degrees C], resulted in metal removal yields of 93% Cu, 97% Pb, 89% Sb, and 70% Zn in Batoche soil and 85% Cu, 96% Pb, 59% Sb, and 49% Zn in Normandie soil. Subsequently, Sb and other dissolved metals (Cu, Pb, and Zn) were successfully recovered via chemical precipitation/coprecipitation (99.1% Cu, > 99.9% Pb, 95.1% Sb, and 99.9% Zn-Batoche; 90.4% Cu, > 99.7% Pb, 79.1% Sb, and > 99.9% Zn-Normandie) by adding NaOH until pH = 9. 2014 American Society of Civil Engineers.